intel/perf: break GL query stuff away

This stuff is somewhat specific to the GL extension & drivers. On
Vulkan we won't use this, it also made a rather large file.

v2: Fix Android build (Lionel)

Signed-off-by: Lionel Landwerlin <[email protected]>
Acked-by: Jason Ekstrand <[email protected]>
Acked-by: Tapani Pälli <[email protected]>
Reviewed-by: Rafael Antognolli <[email protected]>
Reviewed-by: Mark Janes <[email protected]>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4344>

12 files changed, 1685 insertions, 1601 deletions

diff --git a/src/gallium/drivers/iris/iris_perf.c b/src/gallium/drivers/iris/iris_perf.c
index 784890e4728..ab1d32c1361 100644
--- a/src/gallium/drivers/iris/iris_perf.c
+++ b/src/gallium/drivers/iris/iris_perf.c
@@ -22,7 +22,6 @@
 
 #include "iris_perf.h"
 #include "iris_context.h"
-#include "perf/gen_perf_regs.h"
 
 static void *
 iris_oa_bo_alloc(void *bufmgr, const char *name, uint64_t size)
diff --git a/src/gallium/drivers/iris/iris_perf.h b/src/gallium/drivers/iris/iris_perf.h
index a6c132dfe9c..c1f7ea2072c 100644
--- a/src/gallium/drivers/iris/iris_perf.h
+++ b/src/gallium/drivers/iris/iris_perf.h
@@ -24,6 +24,7 @@
 #define IRIS_PERF_H
 
 #include "perf/gen_perf.h"
+#include "perf/gen_perf_query.h"
 
 void iris_perf_init_vtbl(struct gen_perf_config *cfg);
 
diff --git a/src/gallium/drivers/iris/iris_performance_query.c b/src/gallium/drivers/iris/iris_performance_query.c
index 2f990762315..825f4c44268 100644
--- a/src/gallium/drivers/iris/iris_performance_query.c
+++ b/src/gallium/drivers/iris/iris_performance_query.c
@@ -25,9 +25,6 @@
 #include "iris_context.h"
 #include "iris_perf.h"
 
-#include "perf/gen_perf.h"
-#include "perf/gen_perf_regs.h"
-
 struct iris_perf_query {
    struct gl_perf_query_object base;
    struct gen_perf_query_object *query;
diff --git a/src/gallium/drivers/iris/iris_query.c b/src/gallium/drivers/iris/iris_query.c
index a6e062ded0f..b6481200bde 100644
--- a/src/gallium/drivers/iris/iris_query.c
+++ b/src/gallium/drivers/iris/iris_query.c
@@ -33,7 +33,6 @@
 
 #include <stdio.h>
 #include <errno.h>
-#include "perf/gen_perf.h"
 #include "pipe/p_defines.h"
 #include "pipe/p_state.h"
 #include "pipe/p_context.h"
diff --git a/src/intel/Makefile.sources b/src/intel/Makefile.sources
index 216fe35450e..195ce3e67d8 100644
--- a/src/intel/Makefile.sources
+++ b/src/intel/Makefile.sources
@@ -357,8 +357,10 @@ GEN_PERF_XML_FILES = \
 GEN_PERF_FILES = \
 	perf/gen_perf.c \
 	perf/gen_perf.h \
+	perf/gen_perf_mdapi.c \
 	perf/gen_perf_mdapi.h \
-	perf/gen_perf_mdapi.c
+	perf/gen_perf_query.h \
+	perf/gen_perf_query.c
 
 GEN_PERF_GENERATED_FILES = \
 	perf/gen_perf_metrics.c \
diff --git a/src/intel/perf/gen_perf.c b/src/intel/perf/gen_perf.c
index a654eeb4033..c3c7f2e891a 100644
--- a/src/intel/perf/gen_perf.c
+++ b/src/intel/perf/gen_perf.c
@@ -36,345 +36,23 @@
 #include <drm-uapi/i915_drm.h>
 
 #include "common/gen_gem.h"
-#include "gen_perf.h"
-#include "gen_perf_regs.h"
-#include "perf/gen_perf_mdapi.h"
-#include "perf/gen_perf_metrics.h"
 
 #include "dev/gen_debug.h"
 #include "dev/gen_device_info.h"
+
+#include "perf/gen_perf.h"
+#include "perf/gen_perf_regs.h"
+#include "perf/gen_perf_mdapi.h"
+#include "perf/gen_perf_metrics.h"
+
 #include "util/bitscan.h"
 #include "util/mesa-sha1.h"
 #include "util/u_math.h"
 
 #define FILE_DEBUG_FLAG DEBUG_PERFMON
-#define MI_RPC_BO_SIZE              4096
-#define MI_FREQ_START_OFFSET_BYTES  (3072)
-#define MI_RPC_BO_END_OFFSET_BYTES  (MI_RPC_BO_SIZE / 2)
-#define MI_FREQ_END_OFFSET_BYTES    (3076)
-
-#define MAP_READ  (1 << 0)
-#define MAP_WRITE (1 << 1)
 
 #define OA_REPORT_INVALID_CTX_ID (0xffffffff)
 
-/**
- * Periodic OA samples are read() into these buffer structures via the
- * i915 perf kernel interface and appended to the
- * perf_ctx->sample_buffers linked list. When we process the
- * results of an OA metrics query we need to consider all the periodic
- * samples between the Begin and End MI_REPORT_PERF_COUNT command
- * markers.
- *
- * 'Periodic' is a simplification as there are other automatic reports
- * written by the hardware also buffered here.
- *
- * Considering three queries, A, B and C:
- *
- *  Time ---->
- *                ________________A_________________
- *                |                                |
- *                | ________B_________ _____C___________
- *                | |                | |           |   |
- *
- * And an illustration of sample buffers read over this time frame:
- * [HEAD ][     ][     ][     ][     ][     ][     ][     ][TAIL ]
- *
- * These nodes may hold samples for query A:
- * [     ][     ][  A  ][  A  ][  A  ][  A  ][  A  ][     ][     ]
- *
- * These nodes may hold samples for query B:
- * [     ][     ][  B  ][  B  ][  B  ][     ][     ][     ][     ]
- *
- * These nodes may hold samples for query C:
- * [     ][     ][     ][     ][     ][  C  ][  C  ][  C  ][     ]
- *
- * The illustration assumes we have an even distribution of periodic
- * samples so all nodes have the same size plotted against time:
- *
- * Note, to simplify code, the list is never empty.
- *
- * With overlapping queries we can see that periodic OA reports may
- * relate to multiple queries and care needs to be take to keep
- * track of sample buffers until there are no queries that might
- * depend on their contents.
- *
- * We use a node ref counting system where a reference ensures that a
- * node and all following nodes can't be freed/recycled until the
- * reference drops to zero.
- *
- * E.g. with a ref of one here:
- * [  0  ][  0  ][  1  ][  0  ][  0  ][  0  ][  0  ][  0  ][  0  ]
- *
- * These nodes could be freed or recycled ("reaped"):
- * [  0  ][  0  ]
- *
- * These must be preserved until the leading ref drops to zero:
- *               [  1  ][  0  ][  0  ][  0  ][  0  ][  0  ][  0  ]
- *
- * When a query starts we take a reference on the current tail of
- * the list, knowing that no already-buffered samples can possibly
- * relate to the newly-started query. A pointer to this node is
- * also saved in the query object's ->oa.samples_head.
- *
- * E.g. starting query A while there are two nodes in .sample_buffers:
- *                ________________A________
- *                |
- *
- * [  0  ][  1  ]
- *           ^_______ Add a reference and store pointer to node in
- *                    A->oa.samples_head
- *
- * Moving forward to when the B query starts with no new buffer nodes:
- * (for reference, i915 perf reads() are only done when queries finish)
- *                ________________A_______
- *                | ________B___
- *                | |
- *
- * [  0  ][  2  ]
- *           ^_______ Add a reference and store pointer to
- *                    node in B->oa.samples_head
- *
- * Once a query is finished, after an OA query has become 'Ready',
- * once the End OA report has landed and after we we have processed
- * all the intermediate periodic samples then we drop the
- * ->oa.samples_head reference we took at the start.
- *
- * So when the B query has finished we have:
- *                ________________A________
- *                | ______B___________
- *                | |                |
- * [  0  ][  1  ][  0  ][  0  ][  0  ]
- *           ^_______ Drop B->oa.samples_head reference
- *
- * We still can't free these due to the A->oa.samples_head ref:
- *        [  1  ][  0  ][  0  ][  0  ]
- *
- * When the A query finishes: (note there's a new ref for C's samples_head)
- *                ________________A_________________
- *                |                                |
- *                |                    _____C_________
- *                |                    |           |
- * [  0  ][  0  ][  0  ][  0  ][  1  ][  0  ][  0  ]
- *           ^_______ Drop A->oa.samples_head reference
- *
- * And we can now reap these nodes up to the C->oa.samples_head:
- * [  X  ][  X  ][  X  ][  X  ]
- *                  keeping -> [  1  ][  0  ][  0  ]
- *
- * We reap old sample buffers each time we finish processing an OA
- * query by iterating the sample_buffers list from the head until we
- * find a referenced node and stop.
- *
- * Reaped buffers move to a perfquery.free_sample_buffers list and
- * when we come to read() we first look to recycle a buffer from the
- * free_sample_buffers list before allocating a new buffer.
- */
-struct oa_sample_buf {
-   struct exec_node link;
-   int refcount;
-   int len;
-   uint8_t buf[I915_PERF_OA_SAMPLE_SIZE * 10];
-   uint32_t last_timestamp;
-};
-
-/**
- * gen representation of a performance query object.
- *
- * NB: We want to keep this structure relatively lean considering that
- * applications may expect to allocate enough objects to be able to
- * query around all draw calls in a frame.
- */
-struct gen_perf_query_object
-{
-   const struct gen_perf_query_info *queryinfo;
-
-   /* See query->kind to know which state below is in use... */
-   union {
-      struct {
-
-         /**
-          * BO containing OA counter snapshots at query Begin/End time.
-          */
-         void *bo;
-
-         /**
-          * Address of mapped of @bo
-          */
-         void *map;
-
-         /**
-          * The MI_REPORT_PERF_COUNT command lets us specify a unique
-          * ID that will be reflected in the resulting OA report
-          * that's written by the GPU. This is the ID we're expecting
-          * in the begin report and the the end report should be
-          * @begin_report_id + 1.
-          */
-         int begin_report_id;
-
-         /**
-          * Reference the head of the brw->perfquery.sample_buffers
-          * list at the time that the query started (so we only need
-          * to look at nodes after this point when looking for samples
-          * related to this query)
-          *
-          * (See struct brw_oa_sample_buf description for more details)
-          */
-         struct exec_node *samples_head;
-
-         /**
-          * false while in the unaccumulated_elements list, and set to
-          * true when the final, end MI_RPC snapshot has been
-          * accumulated.
-          */
-         bool results_accumulated;
-
-         /**
-          * Frequency of the GT at begin and end of the query.
-          */
-         uint64_t gt_frequency[2];
-
-         /**
-          * Accumulated OA results between begin and end of the query.
-          */
-         struct gen_perf_query_result result;
-      } oa;
-
-      struct {
-         /**
-          * BO containing starting and ending snapshots for the
-          * statistics counters.
-          */
-         void *bo;
-      } pipeline_stats;
-   };
-};
-
-struct gen_perf_context {
-   struct gen_perf_config *perf;
-
-   void * ctx;  /* driver context (eg, brw_context) */
-   void * bufmgr;
-   const struct gen_device_info *devinfo;
-
-   uint32_t hw_ctx;
-   int drm_fd;
-
-   /* The i915 perf stream we open to setup + enable the OA counters */
-   int oa_stream_fd;
-
-   /* An i915 perf stream fd gives exclusive access to the OA unit that will
-    * report counter snapshots for a specific counter set/profile in a
-    * specific layout/format so we can only start OA queries that are
-    * compatible with the currently open fd...
-    */
-   int current_oa_metrics_set_id;
-   int current_oa_format;
-
-   /* List of buffers containing OA reports */
-   struct exec_list sample_buffers;
-
-   /* Cached list of empty sample buffers */
-   struct exec_list free_sample_buffers;
-
-   int n_active_oa_queries;
-   int n_active_pipeline_stats_queries;
-
-   /* The number of queries depending on running OA counters which
-    * extends beyond brw_end_perf_query() since we need to wait until
-    * the last MI_RPC command has parsed by the GPU.
-    *
-    * Accurate accounting is important here as emitting an
-    * MI_REPORT_PERF_COUNT command while the OA unit is disabled will
-    * effectively hang the gpu.
-    */
-   int n_oa_users;
-
-   /* To help catch an spurious problem with the hardware or perf
-    * forwarding samples, we emit each MI_REPORT_PERF_COUNT command
-    * with a unique ID that we can explicitly check for...
-    */
-   int next_query_start_report_id;
-
-   /**
-    * An array of queries whose results haven't yet been assembled
-    * based on the data in buffer objects.
-    *
-    * These may be active, or have already ended.  However, the
-    * results have not been requested.
-    */
-   struct gen_perf_query_object **unaccumulated;
-   int unaccumulated_elements;
-   int unaccumulated_array_size;
-
-   /* The total number of query objects so we can relinquish
-    * our exclusive access to perf if the application deletes
-    * all of its objects. (NB: We only disable perf while
-    * there are no active queries)
-    */
-   int n_query_instances;
-};
-
-const struct gen_perf_query_info*
-gen_perf_query_info(const struct gen_perf_query_object *query)
-{
-   return query->queryinfo;
-}
-
-struct gen_perf_context *
-gen_perf_new_context(void *parent)
-{
-   struct gen_perf_context *ctx = rzalloc(parent, struct gen_perf_context);
-   if (! ctx)
-      fprintf(stderr, "%s: failed to alloc context\n", __func__);
-   return ctx;
-}
-
-struct gen_perf_config *
-gen_perf_config(struct gen_perf_context *ctx)
-{
-   return ctx->perf;
-}
-
-struct gen_perf_query_object *
-gen_perf_new_query(struct gen_perf_context *perf_ctx, unsigned query_index)
-{
-   const struct gen_perf_query_info *query =
-      &perf_ctx->perf->queries[query_index];
-   struct gen_perf_query_object *obj =
-      calloc(1, sizeof(struct gen_perf_query_object));
-
-   if (!obj)
-      return NULL;
-
-   obj->queryinfo = query;
-
-   perf_ctx->n_query_instances++;
-   return obj;
-}
-
-int
-gen_perf_active_queries(struct gen_perf_context *perf_ctx,
-                        const struct gen_perf_query_info *query)
-{
-   assert(perf_ctx->n_active_oa_queries == 0 || perf_ctx->n_active_pipeline_stats_queries == 0);
-
-   switch (query->kind) {
-   case GEN_PERF_QUERY_TYPE_OA:
-   case GEN_PERF_QUERY_TYPE_RAW:
-      return perf_ctx->n_active_oa_queries;
-      break;
-
-   case GEN_PERF_QUERY_TYPE_PIPELINE:
-      return perf_ctx->n_active_pipeline_stats_queries;
-      break;
-
-   default:
-      unreachable("Unknown query type");
-      break;
-   }
-}
-
 static inline uint64_t to_user_pointer(void *ptr)
 {
    return (uintptr_t) ptr;
@@ -1415,219 +1093,6 @@ register_mdapi_oa_query(const struct gen_device_info *devinfo,
    }
 }
 
-static uint64_t
-get_metric_id(struct gen_perf_config *perf,
-              const struct gen_perf_query_info *query)
-{
-   /* These queries are know not to ever change, their config ID has been
-    * loaded upon the first query creation. No need to look them up again.
-    */
-   if (query->kind == GEN_PERF_QUERY_TYPE_OA)
-      return query->oa_metrics_set_id;
-
-   assert(query->kind == GEN_PERF_QUERY_TYPE_RAW);
-
-   /* Raw queries can be reprogrammed up by an external application/library.
-    * When a raw query is used for the first time it's id is set to a value !=
-    * 0. When it stops being used the id returns to 0. No need to reload the
-    * ID when it's already loaded.
-    */
-   if (query->oa_metrics_set_id != 0) {
-      DBG("Raw query '%s' guid=%s using cached ID: %"PRIu64"\n",
-          query->name, query->guid, query->oa_metrics_set_id);
-      return query->oa_metrics_set_id;
-   }
-
-   struct gen_perf_query_info *raw_query = (struct gen_perf_query_info *)query;
-   if (!gen_perf_load_metric_id(perf, query->guid,
-                                &raw_query->oa_metrics_set_id)) {
-      DBG("Unable to read query guid=%s ID, falling back to test config\n", query->guid);
-      raw_query->oa_metrics_set_id = 1ULL;
-   } else {
-      DBG("Raw query '%s'guid=%s loaded ID: %"PRIu64"\n",
-          query->name, query->guid, query->oa_metrics_set_id);
-   }
-   return query->oa_metrics_set_id;
-}
-
-static struct oa_sample_buf *
-get_free_sample_buf(struct gen_perf_context *perf_ctx)
-{
-   struct exec_node *node = exec_list_pop_head(&perf_ctx->free_sample_buffers);
-   struct oa_sample_buf *buf;
-
-   if (node)
-      buf = exec_node_data(struct oa_sample_buf, node, link);
-   else {
-      buf = ralloc_size(perf_ctx->perf, sizeof(*buf));
-
-      exec_node_init(&buf->link);
-      buf->refcount = 0;
-   }
-   buf->len = 0;
-
-   return buf;
-}
-
-static void
-reap_old_sample_buffers(struct gen_perf_context *perf_ctx)
-{
-   struct exec_node *tail_node =
-      exec_list_get_tail(&perf_ctx->sample_buffers);
-   struct oa_sample_buf *tail_buf =
-      exec_node_data(struct oa_sample_buf, tail_node, link);
-
-   /* Remove all old, unreferenced sample buffers walking forward from
-    * the head of the list, except always leave at least one node in
-    * the list so we always have a node to reference when we Begin
-    * a new query.
-    */
-   foreach_list_typed_safe(struct oa_sample_buf, buf, link,
-                           &perf_ctx->sample_buffers)
-   {
-      if (buf->refcount == 0 && buf != tail_buf) {
-         exec_node_remove(&buf->link);
-         exec_list_push_head(&perf_ctx->free_sample_buffers, &buf->link);
-      } else
-         return;
-   }
-}
-
-static void
-free_sample_bufs(struct gen_perf_context *perf_ctx)
-{
-   foreach_list_typed_safe(struct oa_sample_buf, buf, link,
-                           &perf_ctx->free_sample_buffers)
-      ralloc_free(buf);
-
-   exec_list_make_empty(&perf_ctx->free_sample_buffers);
-}
-
-/******************************************************************************/
-
-/**
- * Emit MI_STORE_REGISTER_MEM commands to capture all of the
- * pipeline statistics for the performance query object.
- */
-static void
-snapshot_statistics_registers(struct gen_perf_context *ctx,
-                              struct gen_perf_query_object *obj,
-                              uint32_t offset_in_bytes)
-{
-   struct gen_perf_config *perf = ctx->perf;
-   const struct gen_perf_query_info *query = obj->queryinfo;
-   const int n_counters = query->n_counters;
-
-   for (int i = 0; i < n_counters; i++) {
-      const struct gen_perf_query_counter *counter = &query->counters[i];
-
-      assert(counter->data_type == GEN_PERF_COUNTER_DATA_TYPE_UINT64);
-
-      perf->vtbl.store_register_mem(ctx->ctx, obj->pipeline_stats.bo,
-                                    counter->pipeline_stat.reg, 8,
-                                    offset_in_bytes + i * sizeof(uint64_t));
-   }
-}
-
-static void
-snapshot_freq_register(struct gen_perf_context *ctx,
-                       struct gen_perf_query_object *query,
-                       uint32_t bo_offset)
-{
-   struct gen_perf_config *perf = ctx->perf;
-   const struct gen_device_info *devinfo = ctx->devinfo;
-
-   if (devinfo->gen == 8 && !devinfo->is_cherryview)
-      perf->vtbl.store_register_mem(ctx->ctx, query->oa.bo, GEN7_RPSTAT1, 4, bo_offset);
-   else if (devinfo->gen >= 9)
-      perf->vtbl.store_register_mem(ctx->ctx, query->oa.bo, GEN9_RPSTAT0, 4, bo_offset);
-}
-
-static void
-gen_perf_close(struct gen_perf_context *perfquery,
-               const struct gen_perf_query_info *query)
-{
-   if (perfquery->oa_stream_fd != -1) {
-      close(perfquery->oa_stream_fd);
-      perfquery->oa_stream_fd = -1;
-   }
-   if (query->kind == GEN_PERF_QUERY_TYPE_RAW) {
-      struct gen_perf_query_info *raw_query =
-         (struct gen_perf_query_info *) query;
-      raw_query->oa_metrics_set_id = 0;
-   }
-}
-
-static bool
-gen_perf_open(struct gen_perf_context *perf_ctx,
-              int metrics_set_id,
-              int report_format,
-              int period_exponent,
-              int drm_fd,
-              uint32_t ctx_id)
-{
-   uint64_t properties[] = {
-      /* Single context sampling */
-      DRM_I915_PERF_PROP_CTX_HANDLE, ctx_id,
-
-      /* Include OA reports in samples */
-      DRM_I915_PERF_PROP_SAMPLE_OA, true,
-
-      /* OA unit configuration */
-      DRM_I915_PERF_PROP_OA_METRICS_SET, metrics_set_id,
-      DRM_I915_PERF_PROP_OA_FORMAT, report_format,
-      DRM_I915_PERF_PROP_OA_EXPONENT, period_exponent,
-   };
-   struct drm_i915_perf_open_param param = {
-      .flags = I915_PERF_FLAG_FD_CLOEXEC |
-               I915_PERF_FLAG_FD_NONBLOCK |
-               I915_PERF_FLAG_DISABLED,
-      .num_properties = ARRAY_SIZE(properties) / 2,
-      .properties_ptr = (uintptr_t) properties,
-   };
-   int fd = gen_ioctl(drm_fd, DRM_IOCTL_I915_PERF_OPEN, &param);
-   if (fd == -1) {
-      DBG("Error opening gen perf OA stream: %m\n");
-      return false;
-   }
-
-   perf_ctx->oa_stream_fd = fd;
-
-   perf_ctx->current_oa_metrics_set_id = metrics_set_id;
-   perf_ctx->current_oa_format = report_format;
-
-   return true;
-}
-
-static bool
-inc_n_users(struct gen_perf_context *perf_ctx)
-{
-   if (perf_ctx->n_oa_users == 0 &&
-       gen_ioctl(perf_ctx->oa_stream_fd, I915_PERF_IOCTL_ENABLE, 0) < 0)
-   {
-      return false;
-   }
-   ++perf_ctx->n_oa_users;
-
-   return true;
-}
-
-static void
-dec_n_users(struct gen_perf_context *perf_ctx)
-{
-   /* Disabling the i915 perf stream will effectively disable the OA
-    * counters.  Note it's important to be sure there are no outstanding
-    * MI_RPC commands at this point since they could stall the CS
-    * indefinitely once OACONTROL is disabled.
-    */
-   --perf_ctx->n_oa_users;
-   if (perf_ctx->n_oa_users == 0 &&
-       gen_ioctl(perf_ctx->oa_stream_fd, I915_PERF_IOCTL_DISABLE, 0) < 0)
-   {
-      DBG("WARNING: Error disabling gen perf stream: %m\n");
-   }
-}
-
 void
 gen_perf_init_metrics(struct gen_perf_config *perf_cfg,
                       const struct gen_device_info *devinfo,
@@ -1638,1011 +1103,3 @@ gen_perf_init_metrics(struct gen_perf_config *perf_cfg,
    if (load_oa_metrics(perf_cfg, drm_fd, devinfo))
       register_mdapi_oa_query(devinfo, perf_cfg);
 }
-
-void
-gen_perf_init_context(struct gen_perf_context *perf_ctx,
-                      struct gen_perf_config *perf_cfg,
-                      void * ctx,  /* driver context (eg, brw_context) */
-                      void * bufmgr,  /* eg brw_bufmgr */
-                      const struct gen_device_info *devinfo,
-                      uint32_t hw_ctx,
-                      int drm_fd)
-{
-   perf_ctx->perf = perf_cfg;
-   perf_ctx->ctx = ctx;
-   perf_ctx->bufmgr = bufmgr;
-   perf_ctx->drm_fd = drm_fd;
-   perf_ctx->hw_ctx = hw_ctx;
-   perf_ctx->devinfo = devinfo;
-
-   perf_ctx->unaccumulated =
-      ralloc_array(ctx, struct gen_perf_query_object *, 2);
-   perf_ctx->unaccumulated_elements = 0;
-   perf_ctx->unaccumulated_array_size = 2;
-
-   exec_list_make_empty(&perf_ctx->sample_buffers);
-   exec_list_make_empty(&perf_ctx->free_sample_buffers);
-
-   /* It's convenient to guarantee that this linked list of sample
-    * buffers is never empty so we add an empty head so when we
-    * Begin an OA query we can always take a reference on a buffer
-    * in this list.
-    */
-   struct oa_sample_buf *buf = get_free_sample_buf(perf_ctx);
-   exec_list_push_head(&perf_ctx->sample_buffers, &buf->link);
-
-   perf_ctx->oa_stream_fd = -1;
-   perf_ctx->next_query_start_report_id = 1000;
-}
-
-/**
- * Add a query to the global list of "unaccumulated queries."
- *
- * Queries are tracked here until all the associated OA reports have
- * been accumulated via accumulate_oa_reports() after the end
- * MI_REPORT_PERF_COUNT has landed in query->oa.bo.
- */
-static void
-add_to_unaccumulated_query_list(struct gen_perf_context *perf_ctx,
-                                struct gen_perf_query_object *obj)
-{
-   if (perf_ctx->unaccumulated_elements >=
-       perf_ctx->unaccumulated_array_size)
-   {
-      perf_ctx->unaccumulated_array_size *= 1.5;
-      perf_ctx->unaccumulated =
-         reralloc(perf_ctx->ctx, perf_ctx->unaccumulated,
-                  struct gen_perf_query_object *,
-                  perf_ctx->unaccumulated_array_size);
-   }
-
-   perf_ctx->unaccumulated[perf_ctx->unaccumulated_elements++] = obj;
-}
-
-bool
-gen_perf_begin_query(struct gen_perf_context *perf_ctx,
-                     struct gen_perf_query_object *query)
-{
-   struct gen_perf_config *perf_cfg = perf_ctx->perf;
-   const struct gen_perf_query_info *queryinfo = query->queryinfo;
-
-   /* XXX: We have to consider that the command parser unit that parses batch
-    * buffer commands and is used to capture begin/end counter snapshots isn't
-    * implicitly synchronized with what's currently running across other GPU
-    * units (such as the EUs running shaders) that the performance counters are
-    * associated with.
-    *
-    * The intention of performance queries is to measure the work associated
-    * with commands between the begin/end delimiters and so for that to be the
-    * case we need to explicitly synchronize the parsing of commands to capture
-    * Begin/End counter snapshots with what's running across other parts of the
-    * GPU.
-    *
-    * When the command parser reaches a Begin marker it effectively needs to
-    * drain everything currently running on the GPU until the hardware is idle
-    * before capturing the first snapshot of counters - otherwise the results
-    * would also be measuring the effects of earlier commands.
-    *
-    * When the command parser reaches an End marker it needs to stall until
-    * everything currently running on the GPU has finished before capturing the
-    * end snapshot - otherwise the results won't be a complete representation
-    * of the work.
-    *
-    * To achieve this, we stall the pipeline at pixel scoreboard (prevent any
-    * additional work to be processed by the pipeline until all pixels of the
-    * previous draw has be completed).
-    *
-    * N.B. The final results are based on deltas of counters between (inside)
-    * Begin/End markers so even though the total wall clock time of the
-    * workload is stretched by larger pipeline bubbles the bubbles themselves
-    * are generally invisible to the query results. Whether that's a good or a
-    * bad thing depends on the use case. For a lower real-time impact while
-    * capturing metrics then periodic sampling may be a better choice than
-    * INTEL_performance_query.
-    *
-    *
-    * This is our Begin synchronization point to drain current work on the
-    * GPU before we capture our first counter snapshot...
-    */
-   perf_cfg->vtbl.emit_stall_at_pixel_scoreboard(perf_ctx->ctx);
-
-   switch (queryinfo->kind) {
-   case GEN_PERF_QUERY_TYPE_OA:
-   case GEN_PERF_QUERY_TYPE_RAW: {
-
-      /* Opening an i915 perf stream implies exclusive access to the OA unit
-       * which will generate counter reports for a specific counter set with a
-       * specific layout/format so we can't begin any OA based queries that
-       * require a different counter set or format unless we get an opportunity
-       * to close the stream and open a new one...
-       */
-      uint64_t metric_id = get_metric_id(perf_ctx->perf, queryinfo);
-
-      if (perf_ctx->oa_stream_fd != -1 &&
-          perf_ctx->current_oa_metrics_set_id != metric_id) {
-
-         if (perf_ctx->n_oa_users != 0) {
-            DBG("WARNING: Begin failed already using perf config=%i/%"PRIu64"\n",
-                perf_ctx->current_oa_metrics_set_id, metric_id);
-            return false;
-         } else
-            gen_perf_close(perf_ctx, queryinfo);
-      }
-
-      /* If the OA counters aren't already on, enable them. */
-      if (perf_ctx->oa_stream_fd == -1) {
-         const struct gen_device_info *devinfo = perf_ctx->devinfo;
-
-         /* The period_exponent gives a sampling period as follows:
-          *   sample_period = timestamp_period * 2^(period_exponent + 1)
-          *
-          * The timestamps increments every 80ns (HSW), ~52ns (GEN9LP) or
-          * ~83ns (GEN8/9).
-          *
-          * The counter overflow period is derived from the EuActive counter
-          * which reads a counter that increments by the number of clock
-          * cycles multiplied by the number of EUs. It can be calculated as:
-          *
-          * 2^(number of bits in A counter) / (n_eus * max_gen_freq * 2)
-          *
-          * (E.g. 40 EUs @ 1GHz = ~53ms)
-          *
-          * We select a sampling period inferior to that overflow period to
-          * ensure we cannot see more than 1 counter overflow, otherwise we
-          * could loose information.
-          */
-
-         int a_counter_in_bits = 32;
-         if (devinfo->gen >= 8)
-            a_counter_in_bits = 40;
-
-         uint64_t overflow_period = pow(2, a_counter_in_bits) / (perf_cfg->sys_vars.n_eus *
-             /* drop 1GHz freq to have units in nanoseconds */
-             2);
-
-         DBG("A counter overflow period: %"PRIu64"ns, %"PRIu64"ms (n_eus=%"PRIu64")\n",
-             overflow_period, overflow_period / 1000000ul, perf_cfg->sys_vars.n_eus);
-
-         int period_exponent = 0;
-         uint64_t prev_sample_period, next_sample_period;
-         for (int e = 0; e < 30; e++) {
-            prev_sample_period = 1000000000ull * pow(2, e + 1) / devinfo->timestamp_frequency;
-            next_sample_period = 1000000000ull * pow(2, e + 2) / devinfo->timestamp_frequency;
-
-            /* Take the previous sampling period, lower than the overflow
-             * period.
-             */
-            if (prev_sample_period < overflow_period &&
-                next_sample_period > overflow_period)
-               period_exponent = e + 1;
-         }
-
-         if (period_exponent == 0) {
-            DBG("WARNING: enable to find a sampling exponent\n");
-            return false;
-         }
-
-         DBG("OA sampling exponent: %i ~= %"PRIu64"ms\n", period_exponent,
-             prev_sample_period / 1000000ul);
-
-         if (!gen_perf_open(perf_ctx, metric_id, queryinfo->oa_format,
-                            period_exponent, perf_ctx->drm_fd,
-                            perf_ctx->hw_ctx))
-            return false;
-      } else {
-         assert(perf_ctx->current_oa_metrics_set_id == metric_id &&
-                perf_ctx->current_oa_format == queryinfo->oa_format);
-      }
-
-      if (!inc_n_users(perf_ctx)) {
-         DBG("WARNING: Error enabling i915 perf stream: %m\n");
-         return false;
-      }
-
-      if (query->oa.bo) {
-         perf_cfg->vtbl.bo_unreference(query->oa.bo);
-         query->oa.bo = NULL;
-      }
-
-      query->oa.bo = perf_cfg->vtbl.bo_alloc(perf_ctx->bufmgr,
-                                             "perf. query OA MI_RPC bo",
-                                             MI_RPC_BO_SIZE);
-#ifdef DEBUG
-      /* Pre-filling the BO helps debug whether writes landed. */
-      void *map = perf_cfg->vtbl.bo_map(perf_ctx->ctx, query->oa.bo, MAP_WRITE);
-      memset(map, 0x80, MI_RPC_BO_SIZE);
-      perf_cfg->vtbl.bo_unmap(query->oa.bo);
-#endif
-
-      query->oa.begin_report_id = perf_ctx->next_query_start_report_id;
-      perf_ctx->next_query_start_report_id += 2;
-
-      /* Take a starting OA counter snapshot. */
-      perf_cfg->vtbl.emit_mi_report_perf_count(perf_ctx->ctx, query->oa.bo, 0,
-                                               query->oa.begin_report_id);
-      snapshot_freq_register(perf_ctx, query, MI_FREQ_START_OFFSET_BYTES);
-
-      ++perf_ctx->n_active_oa_queries;
-
-      /* No already-buffered samples can possibly be associated with this query
-       * so create a marker within the list of sample buffers enabling us to
-       * easily ignore earlier samples when processing this query after
-       * completion.
-       */
-      assert(!exec_list_is_empty(&perf_ctx->sample_buffers));
-      query->oa.samples_head = exec_list_get_tail(&perf_ctx->sample_buffers);
-
-      struct oa_sample_buf *buf =
-         exec_node_data(struct oa_sample_buf, query->oa.samples_head, link);
-
-      /* This reference will ensure that future/following sample
-       * buffers (that may relate to this query) can't be freed until
-       * this drops to zero.
-       */
-      buf->refcount++;
-
-      gen_perf_query_result_clear(&query->oa.result);
-      query->oa.results_accumulated = false;
-
-      add_to_unaccumulated_query_list(perf_ctx, query);
-      break;
-   }
-
-   case GEN_PERF_QUERY_TYPE_PIPELINE:
-      if (query->pipeline_stats.bo) {
-         perf_cfg->vtbl.bo_unreference(query->pipeline_stats.bo);
-         query->pipeline_stats.bo = NULL;
-      }
-
-      query->pipeline_stats.bo =
-         perf_cfg->vtbl.bo_alloc(perf_ctx->bufmgr,
-                                 "perf. query pipeline stats bo",
-                                 STATS_BO_SIZE);
-
-      /* Take starting snapshots. */
-      snapshot_statistics_registers(perf_ctx, query, 0);
-
-      ++perf_ctx->n_active_pipeline_stats_queries;
-      break;
-
-   default:
-      unreachable("Unknown query type");
-      break;
-   }
-
-   return true;
-}
-
-void
-gen_perf_end_query(struct gen_perf_context *perf_ctx,
-                   struct gen_perf_query_object *query)
-{
-   struct gen_perf_config *perf_cfg = perf_ctx->perf;
-
-   /* Ensure that the work associated with the queried commands will have
-    * finished before taking our query end counter readings.
-    *
-    * For more details see comment in brw_begin_perf_query for
-    * corresponding flush.
-    */
-   perf_cfg->vtbl.emit_stall_at_pixel_scoreboard(perf_ctx->ctx);
-
-   switch (query->queryinfo->kind) {
-   case GEN_PERF_QUERY_TYPE_OA:
-   case GEN_PERF_QUERY_TYPE_RAW:
-
-      /* NB: It's possible that the query will have already been marked
-       * as 'accumulated' if an error was seen while reading samples
-       * from perf. In this case we mustn't try and emit a closing
-       * MI_RPC command in case the OA unit has already been disabled
-       */
-      if (!query->oa.results_accumulated) {
-         /* Take an ending OA counter snapshot. */
-         snapshot_freq_register(perf_ctx, query, MI_FREQ_END_OFFSET_BYTES);
-         perf_cfg->vtbl.emit_mi_report_perf_count(perf_ctx->ctx, query->oa.bo,
-                                             MI_RPC_BO_END_OFFSET_BYTES,
-                                             query->oa.begin_report_id + 1);
-      }
-
-      --perf_ctx->n_active_oa_queries;
-
-      /* NB: even though the query has now ended, it can't be accumulated
-       * until the end MI_REPORT_PERF_COUNT snapshot has been written
-       * to query->oa.bo
-       */
-      break;
-
-   case GEN_PERF_QUERY_TYPE_PIPELINE:
-      snapshot_statistics_registers(perf_ctx, query,
-                                    STATS_BO_END_OFFSET_BYTES);
-      --perf_ctx->n_active_pipeline_stats_queries;
-      break;
-
-   default:
-      unreachable("Unknown query type");
-      break;
-   }
-}
-
-enum OaReadStatus {
-   OA_READ_STATUS_ERROR,
-   OA_READ_STATUS_UNFINISHED,
-   OA_READ_STATUS_FINISHED,
-};
-
-static enum OaReadStatus
-read_oa_samples_until(struct gen_perf_context *perf_ctx,
-                      uint32_t start_timestamp,
-                      uint32_t end_timestamp)
-{
-   struct exec_node *tail_node =
-      exec_list_get_tail(&perf_ctx->sample_buffers);
-   struct oa_sample_buf *tail_buf =
-      exec_node_data(struct oa_sample_buf, tail_node, link);
-   uint32_t last_timestamp =
-      tail_buf->len == 0 ? start_timestamp : tail_buf->last_timestamp;
-
-   while (1) {
-      struct oa_sample_buf *buf = get_free_sample_buf(perf_ctx);
-      uint32_t offset;
-      int len;
-
-      while ((len = read(perf_ctx->oa_stream_fd, buf->buf,
-                         sizeof(buf->buf))) < 0 && errno == EINTR)
-         ;
-
-      if (len <= 0) {
-         exec_list_push_tail(&perf_ctx->free_sample_buffers, &buf->link);
-
-         if (len < 0) {
-            if (errno == EAGAIN) {
-               return ((last_timestamp - start_timestamp) < INT32_MAX &&
-                       (last_timestamp - start_timestamp) >=
-                       (end_timestamp - start_timestamp)) ?
-                      OA_READ_STATUS_FINISHED :
-                      OA_READ_STATUS_UNFINISHED;
-            } else {
-               DBG("Error reading i915 perf samples: %m\n");
-            }
-         } else
-            DBG("Spurious EOF reading i915 perf samples\n");
-
-         return OA_READ_STATUS_ERROR;
-      }
-
-      buf->len = len;
-      exec_list_push_tail(&perf_ctx->sample_buffers, &buf->link);
-
-      /* Go through the reports and update the last timestamp. */
-      offset = 0;
-      while (offset < buf->len) {
-         const struct drm_i915_perf_record_header *header =
-            (const struct drm_i915_perf_record_header *) &buf->buf[offset];
-         uint32_t *report = (uint32_t *) (header + 1);
-
-         if (header->type == DRM_I915_PERF_RECORD_SAMPLE)
-            last_timestamp = report[1];
-
-         offset += header->size;
-      }
-
-      buf->last_timestamp = last_timestamp;
-   }
-
-   unreachable("not reached");
-   return OA_READ_STATUS_ERROR;
-}
-
-/**
- * Try to read all the reports until either the delimiting timestamp
- * or an error arises.
- */
-static bool
-read_oa_samples_for_query(struct gen_perf_context *perf_ctx,
-                          struct gen_perf_query_object *query,
-                          void *current_batch)
-{
-   uint32_t *start;
-   uint32_t *last;
-   uint32_t *end;
-   struct gen_perf_config *perf_cfg = perf_ctx->perf;
-
-   /* We need the MI_REPORT_PERF_COUNT to land before we can start
-    * accumulate. */
-   assert(!perf_cfg->vtbl.batch_references(current_batch, query->oa.bo) &&
-          !perf_cfg->vtbl.bo_busy(query->oa.bo));
-
-   /* Map the BO once here and let accumulate_oa_reports() unmap
-    * it. */
-   if (query->oa.map == NULL)
-      query->oa.map = perf_cfg->vtbl.bo_map(perf_ctx->ctx, query->oa.bo, MAP_READ);
-
-   start = last = query->oa.map;
-   end = query->oa.map + MI_RPC_BO_END_OFFSET_BYTES;
-
-   if (start[0] != query->oa.begin_report_id) {
-      DBG("Spurious start report id=%"PRIu32"\n", start[0]);
-      return true;
-   }
-   if (end[0] != (query->oa.begin_report_id + 1)) {
-      DBG("Spurious end report id=%"PRIu32"\n", end[0]);
-      return true;
-   }
-
-   /* Read the reports until the end timestamp. */
-   switch (read_oa_samples_until(perf_ctx, start[1], end[1])) {
-   case OA_READ_STATUS_ERROR:
-      /* Fallthrough and let accumulate_oa_reports() deal with the
-       * error. */
-   case OA_READ_STATUS_FINISHED:
-      return true;
-   case OA_READ_STATUS_UNFINISHED:
-      return false;
-   }
-
-   unreachable("invalid read status");
-   return false;
-}
-
-void
-gen_perf_wait_query(struct gen_perf_context *perf_ctx,
-                    struct gen_perf_query_object *query,
-                    void *current_batch)
-{
-   struct gen_perf_config *perf_cfg = perf_ctx->perf;
-   struct brw_bo *bo = NULL;
-
-   switch (query->queryinfo->kind) {
-   case GEN_PERF_QUERY_TYPE_OA:
-   case GEN_PERF_QUERY_TYPE_RAW:
-      bo = query->oa.bo;
-      break;
-
-   case GEN_PERF_QUERY_TYPE_PIPELINE:
-      bo = query->pipeline_stats.bo;
-      break;
-
-   default:
-      unreachable("Unknown query type");
-      break;
-   }
-
-   if (bo == NULL)
-      return;
-
-   /* If the current batch references our results bo then we need to
-    * flush first...
-    */
-   if (perf_cfg->vtbl.batch_references(current_batch, bo))
-      perf_cfg->vtbl.batchbuffer_flush(perf_ctx->ctx, __FILE__, __LINE__);
-
-   perf_cfg->vtbl.bo_wait_rendering(bo);
-
-   /* Due to a race condition between the OA unit signaling report
-    * availability and the report actually being written into memory,
-    * we need to wait for all the reports to come in before we can
-    * read them.
-    */
-   if (query->queryinfo->kind == GEN_PERF_QUERY_TYPE_OA ||
-       query->queryinfo->kind == GEN_PERF_QUERY_TYPE_RAW) {
-      while (!read_oa_samples_for_query(perf_ctx, query, current_batch))
-         ;
-   }
-}
-
-bool
-gen_perf_is_query_ready(struct gen_perf_context *perf_ctx,
-                        struct gen_perf_query_object *query,
-                        void *current_batch)
-{
-   struct gen_perf_config *perf_cfg = perf_ctx->perf;
-
-   switch (query->queryinfo->kind) {
-   case GEN_PERF_QUERY_TYPE_OA:
-   case GEN_PERF_QUERY_TYPE_RAW:
-      return (query->oa.results_accumulated ||
-              (query->oa.bo &&
-               !perf_cfg->vtbl.batch_references(current_batch, query->oa.bo) &&
-               !perf_cfg->vtbl.bo_busy(query->oa.bo) &&
-               read_oa_samples_for_query(perf_ctx, query, current_batch)));
-   case GEN_PERF_QUERY_TYPE_PIPELINE:
-      return (query->pipeline_stats.bo &&
-              !perf_cfg->vtbl.batch_references(current_batch, query->pipeline_stats.bo) &&
-              !perf_cfg->vtbl.bo_busy(query->pipeline_stats.bo));
-
-   default:
-      unreachable("Unknown query type");
-      break;
-   }
-
-   return false;
-}
-
-/**
- * Remove a query from the global list of unaccumulated queries once
- * after successfully accumulating the OA reports associated with the
- * query in accumulate_oa_reports() or when discarding unwanted query
- * results.
- */
-static void
-drop_from_unaccumulated_query_list(struct gen_perf_context *perf_ctx,
-                                   struct gen_perf_query_object *query)
-{
-   for (int i = 0; i < perf_ctx->unaccumulated_elements; i++) {
-      if (perf_ctx->unaccumulated[i] == query) {
-         int last_elt = --perf_ctx->unaccumulated_elements;
-
-         if (i == last_elt)
-            perf_ctx->unaccumulated[i] = NULL;
-         else {
-            perf_ctx->unaccumulated[i] =
-               perf_ctx->unaccumulated[last_elt];
-         }
-
-         break;
-      }
-   }
-
-   /* Drop our samples_head reference so that associated periodic
-    * sample data buffers can potentially be reaped if they aren't
-    * referenced by any other queries...
-    */
-
-   struct oa_sample_buf *buf =
-      exec_node_data(struct oa_sample_buf, query->oa.samples_head, link);
-
-   assert(buf->refcount > 0);
-   buf->refcount--;
-
-   query->oa.samples_head = NULL;
-
-   reap_old_sample_buffers(perf_ctx);
-}
-
-/* In general if we see anything spurious while accumulating results,
- * we don't try and continue accumulating the current query, hoping
- * for the best, we scrap anything outstanding, and then hope for the
- * best with new queries.
- */
-static void
-discard_all_queries(struct gen_perf_context *perf_ctx)
-{
-   while (perf_ctx->unaccumulated_elements) {
-      struct gen_perf_query_object *query = perf_ctx->unaccumulated[0];
-
-      query->oa.results_accumulated = true;
-      drop_from_unaccumulated_query_list(perf_ctx, query);
-
-      dec_n_users(perf_ctx);
-   }
-}
-
-/* Looks for the validity bit of context ID (dword 2) of an OA report. */
-static bool
-oa_report_ctx_id_valid(const struct gen_device_info *devinfo,
-                       const uint32_t *report)
-{
-   assert(devinfo->gen >= 8);
-   if (devinfo->gen == 8)
-      return (report[0] & (1 << 25)) != 0;
-   return (report[0] & (1 << 16)) != 0;
-}
-
-/**
- * Accumulate raw OA counter values based on deltas between pairs of
- * OA reports.
- *
- * Accumulation starts from the first report captured via
- * MI_REPORT_PERF_COUNT (MI_RPC) by brw_begin_perf_query() until the
- * last MI_RPC report requested by brw_end_perf_query(). Between these
- * two reports there may also some number of periodically sampled OA
- * reports collected via the i915 perf interface - depending on the
- * duration of the query.
- *
- * These periodic snapshots help to ensure we handle counter overflow
- * correctly by being frequent enough to ensure we don't miss multiple
- * overflows of a counter between snapshots. For Gen8+ the i915 perf
- * snapshots provide the extra context-switch reports that let us
- * subtract out the progress of counters associated with other
- * contexts running on the system.
- */
-static void
-accumulate_oa_reports(struct gen_perf_context *perf_ctx,
-                      struct gen_perf_query_object *query)
-{
-   const struct gen_device_info *devinfo = perf_ctx->devinfo;
-   uint32_t *start;
-   uint32_t *last;
-   uint32_t *end;
-   struct exec_node *first_samples_node;
-   bool last_report_ctx_match = true;
-   int out_duration = 0;
-
-   assert(query->oa.map != NULL);
-
-   start = last = query->oa.map;
-   end = query->oa.map + MI_RPC_BO_END_OFFSET_BYTES;
-
-   if (start[0] != query->oa.begin_report_id) {
-      DBG("Spurious start report id=%"PRIu32"\n", start[0]);
-      goto error;
-   }
-   if (end[0] != (query->oa.begin_report_id + 1)) {
-      DBG("Spurious end report id=%"PRIu32"\n", end[0]);
-      goto error;
-   }
-
-   /* On Gen12+ OA reports are sourced from per context counters, so we don't
-    * ever have to look at the global OA buffer. Yey \o/
-    */
-   if (perf_ctx->devinfo->gen >= 12) {
-      last = start;
-      goto end;
-   }
-
-   /* See if we have any periodic reports to accumulate too... */
-
-   /* N.B. The oa.samples_head was set when the query began and
-    * pointed to the tail of the perf_ctx->sample_buffers list at
-    * the time the query started. Since the buffer existed before the
-    * first MI_REPORT_PERF_COUNT command was emitted we therefore know
-    * that no data in this particular node's buffer can possibly be
-    * associated with the query - so skip ahead one...
-    */
-   first_samples_node = query->oa.samples_head->next;
-
-   foreach_list_typed_from(struct oa_sample_buf, buf, link,
-                           &perf_ctx->sample_buffers,
-                           first_samples_node)
-   {
-      int offset = 0;
-
-      while (offset < buf->len) {
-         const struct drm_i915_perf_record_header *header =
-            (const struct drm_i915_perf_record_header *)(buf->buf + offset);
-
-         assert(header->size != 0);
-         assert(header->size <= buf->len);
-
-         offset += header->size;
-
-         switch (header->type) {
-         case DRM_I915_PERF_RECORD_SAMPLE: {
-            uint32_t *report = (uint32_t *)(header + 1);
-            bool report_ctx_match = true;
-            bool add = true;
-
-            /* Ignore reports that come before the start marker.
-             * (Note: takes care to allow overflow of 32bit timestamps)
-             */
-            if (gen_device_info_timebase_scale(devinfo,
-                                               report[1] - start[1]) > 5000000000) {
-               continue;
-            }
-
-            /* Ignore reports that come after the end marker.
-             * (Note: takes care to allow overflow of 32bit timestamps)
-             */
-            if (gen_device_info_timebase_scale(devinfo,
-                                               report[1] - end[1]) <= 5000000000) {
-               goto end;
-            }
-
-            /* For Gen8+ since the counters continue while other
-             * contexts are running we need to discount any unrelated
-             * deltas. The hardware automatically generates a report
-             * on context switch which gives us a new reference point
-             * to continuing adding deltas from.
-             *
-             * For Haswell we can rely on the HW to stop the progress
-             * of OA counters while any other context is acctive.
-             */
-            if (devinfo->gen >= 8) {
-               /* Consider that the current report matches our context only if
-                * the report says the report ID is valid.
-                */
-               report_ctx_match = oa_report_ctx_id_valid(devinfo, report) &&
-                  report[2] == start[2];
-               if (report_ctx_match)
-                  out_duration = 0;
-               else
-                  out_duration++;
-
-               /* Only add the delta between <last, report> if the last report
-                * was clearly identified as our context, or if we have at most
-                * 1 report without a matching ID.
-                *
-                * The OA unit will sometimes label reports with an invalid
-                * context ID when i915 rewrites the execlist submit register
-                * with the same context as the one currently running. This
-                * happens when i915 wants to notify the HW of ringbuffer tail
-                * register update. We have to consider this report as part of
-                * our context as the 3d pipeline behind the OACS unit is still
-                * processing the operations started at the previous execlist
-                * submission.
-                */
-               add = last_report_ctx_match && out_duration < 2;
-            }
-
-            if (add) {
-               gen_perf_query_result_accumulate(&query->oa.result,
-                                                query->queryinfo,
-                                                last, report);
-            } else {
-               /* We're not adding the delta because we've identified it's not
-                * for the context we filter for. We can consider that the
-                * query was split.
-                */
-               query->oa.result.query_disjoint = true;
-            }
-
-            last = report;
-            last_report_ctx_match = report_ctx_match;
-
-            break;
-         }
-
-         case DRM_I915_PERF_RECORD_OA_BUFFER_LOST:
-             DBG("i915 perf: OA error: all reports lost\n");
-             goto error;
-         case DRM_I915_PERF_RECORD_OA_REPORT_LOST:
-             DBG("i915 perf: OA report lost\n");
-             break;
-         }
-      }
-   }
-
-end:
-
-   gen_perf_query_result_accumulate(&query->oa.result, query->queryinfo,
-                                    last, end);
-
-   query->oa.results_accumulated = true;
-   drop_from_unaccumulated_query_list(perf_ctx, query);
-   dec_n_users(perf_ctx);
-
-   return;
-
-error:
-
-   discard_all_queries(perf_ctx);
-}
-
-void
-gen_perf_delete_query(struct gen_perf_context *perf_ctx,
-                      struct gen_perf_query_object *query)
-{
-   struct gen_perf_config *perf_cfg = perf_ctx->perf;
-
-   /* We can assume that the frontend waits for a query to complete
-    * before ever calling into here, so we don't have to worry about
-    * deleting an in-flight query object.
-    */
-   switch (query->queryinfo->kind) {
-   case GEN_PERF_QUERY_TYPE_OA:
-   case GEN_PERF_QUERY_TYPE_RAW:
-      if (query->oa.bo) {
-         if (!query->oa.results_accumulated) {
-            drop_from_unaccumulated_query_list(perf_ctx, query);
-            dec_n_users(perf_ctx);
-         }
-
-         perf_cfg->vtbl.bo_unreference(query->oa.bo);
-         query->oa.bo = NULL;
-      }
-
-      query->oa.results_accumulated = false;
-      break;
-
-   case GEN_PERF_QUERY_TYPE_PIPELINE:
-      if (query->pipeline_stats.bo) {
-         perf_cfg->vtbl.bo_unreference(query->pipeline_stats.bo);
-         query->pipeline_stats.bo = NULL;
-      }
-      break;
-
-   default:
-      unreachable("Unknown query type");
-      break;
-   }
-
-   /* As an indication that the INTEL_performance_query extension is no
-    * longer in use, it's a good time to free our cache of sample
-    * buffers and close any current i915-perf stream.
-    */
-   if (--perf_ctx->n_query_instances == 0) {
-      free_sample_bufs(perf_ctx);
-      gen_perf_close(perf_ctx, query->queryinfo);
-   }
-
-   free(query);
-}
-
-#define GET_FIELD(word, field) (((word)  & field ## _MASK) >> field ## _SHIFT)
-
-static void
-read_gt_frequency(struct gen_perf_context *perf_ctx,
-                  struct gen_perf_query_object *obj)
-{
-   const struct gen_device_info *devinfo = perf_ctx->devinfo;
-   uint32_t start = *((uint32_t *)(obj->oa.map + MI_FREQ_START_OFFSET_BYTES)),
-      end = *((uint32_t *)(obj->oa.map + MI_FREQ_END_OFFSET_BYTES));
-
-   switch (devinfo->gen) {
-   case 7:
-   case 8:
-      obj->oa.gt_frequency[0] = GET_FIELD(start, GEN7_RPSTAT1_CURR_GT_FREQ) * 50ULL;
-      obj->oa.gt_frequency[1] = GET_FIELD(end, GEN7_RPSTAT1_CURR_GT_FREQ) * 50ULL;
-      break;
-   case 9:
-   case 10:
-   case 11:
-      obj->oa.gt_frequency[0] = GET_FIELD(start, GEN9_RPSTAT0_CURR_GT_FREQ) * 50ULL / 3ULL;
-      obj->oa.gt_frequency[1] = GET_FIELD(end, GEN9_RPSTAT0_CURR_GT_FREQ) * 50ULL / 3ULL;
-      break;
-   default:
-      unreachable("unexpected gen");
-   }
-
-   /* Put the numbers into Hz. */
-   obj->oa.gt_frequency[0] *= 1000000ULL;
-   obj->oa.gt_frequency[1] *= 1000000ULL;
-}
-
-static int
-get_oa_counter_data(struct gen_perf_context *perf_ctx,
-                    struct gen_perf_query_object *query,
-                    size_t data_size,
-                    uint8_t *data)
-{
-   struct gen_perf_config *perf_cfg = perf_ctx->perf;
-   const struct gen_perf_query_info *queryinfo = query->queryinfo;
-   int n_counters = queryinfo->n_counters;
-   int written = 0;
-
-   for (int i = 0; i < n_counters; i++) {
-      const struct gen_perf_query_counter *counter = &queryinfo->counters[i];
-      uint64_t *out_uint64;
-      float *out_float;
-      size_t counter_size = gen_perf_query_counter_get_size(counter);
-
-      if (counter_size) {
-         switch (counter->data_type) {
-         case GEN_PERF_COUNTER_DATA_TYPE_UINT64:
-            out_uint64 = (uint64_t *)(data + counter->offset);
-            *out_uint64 =
-               counter->oa_counter_read_uint64(perf_cfg, queryinfo,
-                                               query->oa.result.accumulator);
-            break;
-         case GEN_PERF_COUNTER_DATA_TYPE_FLOAT:
-            out_float = (float *)(data + counter->offset);
-            *out_float =
-               counter->oa_counter_read_float(perf_cfg, queryinfo,
-                                              query->oa.result.accumulator);
-            break;
-         default:
-            /* So far we aren't using uint32, double or bool32... */
-            unreachable("unexpected counter data type");
-         }
-         written = counter->offset + counter_size;
-      }
-   }
-
-   return written;
-}
-
-static int
-get_pipeline_stats_data(struct gen_perf_context *perf_ctx,
-                        struct gen_perf_query_object *query,
-                        size_t data_size,
-                        uint8_t *data)
-
-{
-   struct gen_perf_config *perf_cfg = perf_ctx->perf;
-   const struct gen_perf_query_info *queryinfo = query->queryinfo;
-   int n_counters = queryinfo->n_counters;
-   uint8_t *p = data;
-
-   uint64_t *start = perf_cfg->vtbl.bo_map(perf_ctx->ctx, query->pipeline_stats.bo, MAP_READ);
-   uint64_t *end = start + (STATS_BO_END_OFFSET_BYTES / sizeof(uint64_t));
-
-   for (int i = 0; i < n_counters; i++) {
-      const struct gen_perf_query_counter *counter = &queryinfo->counters[i];
-      uint64_t value = end[i] - start[i];
-
-      if (counter->pipeline_stat.numerator !=
-          counter->pipeline_stat.denominator) {
-         value *= counter->pipeline_stat.numerator;
-         value /= counter->pipeline_stat.denominator;
-      }
-
-      *((uint64_t *)p) = value;
-      p += 8;
-   }
-
-   perf_cfg->vtbl.bo_unmap(query->pipeline_stats.bo);
-
-   return p - data;
-}
-
-void
-gen_perf_get_query_data(struct gen_perf_context *perf_ctx,
-                        struct gen_perf_query_object *query,
-                        int data_size,
-                        unsigned *data,
-                        unsigned *bytes_written)
-{
-   struct gen_perf_config *perf_cfg = perf_ctx->perf;
-   int written = 0;
-
-   switch (query->queryinfo->kind) {
-   case GEN_PERF_QUERY_TYPE_OA:
-   case GEN_PERF_QUERY_TYPE_RAW:
-      if (!query->oa.results_accumulated) {
-         read_gt_frequency(perf_ctx, query);
-         uint32_t *begin_report = query->oa.map;
-         uint32_t *end_report = query->oa.map + MI_RPC_BO_END_OFFSET_BYTES;
-         gen_perf_query_result_read_frequencies(&query->oa.result,
-                                                perf_ctx->devinfo,
-                                                begin_report,
-                                                end_report);
-         accumulate_oa_reports(perf_ctx, query);
-         assert(query->oa.results_accumulated);
-
-         perf_cfg->vtbl.bo_unmap(query->oa.bo);
-         query->oa.map = NULL;
-      }
-      if (query->queryinfo->kind == GEN_PERF_QUERY_TYPE_OA) {
-         written = get_oa_counter_data(perf_ctx, query, data_size, (uint8_t *)data);
-      } else {
-         const struct gen_device_info *devinfo = perf_ctx->devinfo;
-
-         written = gen_perf_query_result_write_mdapi((uint8_t *)data, data_size,
-                                                     devinfo, &query->oa.result,
-                                                     query->oa.gt_frequency[0],
-                                                     query->oa.gt_frequency[1]);
-      }
-      break;
-
-   case GEN_PERF_QUERY_TYPE_PIPELINE:
-      written = get_pipeline_stats_data(perf_ctx, query, data_size, (uint8_t *)data);
-      break;
-
-   default:
-      unreachable("Unknown query type");
-      break;
-   }
-
-   if (bytes_written)
-      *bytes_written = written;
-}
-
-void
-gen_perf_dump_query_count(struct gen_perf_context *perf_ctx)
-{
-   DBG("Queries: (Open queries = %d, OA users = %d)\n",
-       perf_ctx->n_active_oa_queries, perf_ctx->n_oa_users);
-}
-
-void
-gen_perf_dump_query(struct gen_perf_context *ctx,
-                    struct gen_perf_query_object *obj,
-                    void *current_batch)
-{
-   switch (obj->queryinfo->kind) {
-   case GEN_PERF_QUERY_TYPE_OA:
-   case GEN_PERF_QUERY_TYPE_RAW:
-      DBG("BO: %-4s OA data: %-10s %-15s\n",
-          obj->oa.bo ? "yes," : "no,",
-          gen_perf_is_query_ready(ctx, obj, current_batch) ? "ready," : "not ready,",
-          obj->oa.results_accumulated ? "accumulated" : "not accumulated");
-      break;
-   case GEN_PERF_QUERY_TYPE_PIPELINE:
-      DBG("BO: %-4s\n",
-          obj->pipeline_stats.bo ? "yes" : "no");
-      break;
-   default:
-      unreachable("Unknown query type");
-      break;
-   }
-}
diff --git a/src/intel/perf/gen_perf.h b/src/intel/perf/gen_perf.h
index b0af49ffb2c..8f6fca16aa1 100644
--- a/src/intel/perf/gen_perf.h
+++ b/src/intel/perf/gen_perf.h
@@ -241,9 +241,6 @@ struct gen_perf_config {
    } vtbl;
 };
 
-struct gen_perf_query_object;
-const struct gen_perf_query_info* gen_perf_query_info(const struct gen_perf_query_object *);
-
 void gen_perf_init_metrics(struct gen_perf_config *perf_cfg,
                            const struct gen_device_info *devinfo,
                            int drm_fd);
@@ -283,22 +280,6 @@ void gen_perf_query_result_accumulate(struct gen_perf_query_result *result,
                                       const uint32_t *end);
 void gen_perf_query_result_clear(struct gen_perf_query_result *result);
 
-struct gen_perf_context;
-struct gen_perf_context *gen_perf_new_context(void *parent);
-
-void gen_perf_init_context(struct gen_perf_context *perf_ctx,
-                           struct gen_perf_config *perf_cfg,
-                           void * ctx,  /* driver context (eg, brw_context) */
-                           void * bufmgr,  /* eg brw_bufmgr */
-                           const struct gen_device_info *devinfo,
-                           uint32_t hw_ctx,
-                           int drm_fd);
-
-struct gen_perf_config *gen_perf_config(struct gen_perf_context *ctx);
-
-int gen_perf_active_queries(struct gen_perf_context *perf_ctx,
-                            const struct gen_perf_query_info *query);
-
 static inline size_t
 gen_perf_query_counter_get_size(const struct gen_perf_query_counter *counter)
 {
@@ -325,31 +306,4 @@ gen_perf_new(void *ctx)
    return perf;
 }
 
-struct gen_perf_query_object *
-gen_perf_new_query(struct gen_perf_context *, unsigned query_index);
-
-
-bool gen_perf_begin_query(struct gen_perf_context *perf_ctx,
-                          struct gen_perf_query_object *query);
-void gen_perf_end_query(struct gen_perf_context *perf_ctx,
-                        struct gen_perf_query_object *query);
-void gen_perf_wait_query(struct gen_perf_context *perf_ctx,
-                         struct gen_perf_query_object *query,
-                         void *current_batch);
-bool gen_perf_is_query_ready(struct gen_perf_context *perf_ctx,
-                             struct gen_perf_query_object *query,
-                             void *current_batch);
-void gen_perf_delete_query(struct gen_perf_context *perf_ctx,
-                           struct gen_perf_query_object *query);
-void gen_perf_get_query_data(struct gen_perf_context *perf_ctx,
-                             struct gen_perf_query_object *query,
-                             int data_size,
-                             unsigned *data,
-                             unsigned *bytes_written);
-
-void gen_perf_dump_query_count(struct gen_perf_context *perf_ctx);
-void gen_perf_dump_query(struct gen_perf_context *perf_ctx,
-                         struct gen_perf_query_object *obj,
-                         void *current_batch);
-
 #endif /* GEN_PERF_H */
diff --git a/src/intel/perf/gen_perf_query.c b/src/intel/perf/gen_perf_query.c
new file mode 100644
index 00000000000..1d6743d4153
--- /dev/null
+++ b/src/intel/perf/gen_perf_query.c
@@ -0,0 +1,1584 @@
+/*
+ * Copyright © 2019 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <unistd.h>
+
+#include "common/gen_gem.h"
+
+#include "dev/gen_debug.h"
+#include "dev/gen_device_info.h"
+
+#include "perf/gen_perf.h"
+#include "perf/gen_perf_mdapi.h"
+#include "perf/gen_perf_query.h"
+#include "perf/gen_perf_regs.h"
+
+#include "drm-uapi/i915_drm.h"
+
+#include "util/u_math.h"
+
+#define FILE_DEBUG_FLAG DEBUG_PERFMON
+#define MI_RPC_BO_SIZE              4096
+#define MI_FREQ_START_OFFSET_BYTES  (3072)
+#define MI_RPC_BO_END_OFFSET_BYTES  (MI_RPC_BO_SIZE / 2)
+#define MI_FREQ_END_OFFSET_BYTES    (3076)
+
+#define MAP_READ  (1 << 0)
+#define MAP_WRITE (1 << 1)
+
+/**
+ * Periodic OA samples are read() into these buffer structures via the
+ * i915 perf kernel interface and appended to the
+ * perf_ctx->sample_buffers linked list. When we process the
+ * results of an OA metrics query we need to consider all the periodic
+ * samples between the Begin and End MI_REPORT_PERF_COUNT command
+ * markers.
+ *
+ * 'Periodic' is a simplification as there are other automatic reports
+ * written by the hardware also buffered here.
+ *
+ * Considering three queries, A, B and C:
+ *
+ *  Time ---->
+ *                ________________A_________________
+ *                |                                |
+ *                | ________B_________ _____C___________
+ *                | |                | |           |   |
+ *
+ * And an illustration of sample buffers read over this time frame:
+ * [HEAD ][     ][     ][     ][     ][     ][     ][     ][TAIL ]
+ *
+ * These nodes may hold samples for query A:
+ * [     ][     ][  A  ][  A  ][  A  ][  A  ][  A  ][     ][     ]
+ *
+ * These nodes may hold samples for query B:
+ * [     ][     ][  B  ][  B  ][  B  ][     ][     ][     ][     ]
+ *
+ * These nodes may hold samples for query C:
+ * [     ][     ][     ][     ][     ][  C  ][  C  ][  C  ][     ]
+ *
+ * The illustration assumes we have an even distribution of periodic
+ * samples so all nodes have the same size plotted against time:
+ *
+ * Note, to simplify code, the list is never empty.
+ *
+ * With overlapping queries we can see that periodic OA reports may
+ * relate to multiple queries and care needs to be take to keep
+ * track of sample buffers until there are no queries that might
+ * depend on their contents.
+ *
+ * We use a node ref counting system where a reference ensures that a
+ * node and all following nodes can't be freed/recycled until the
+ * reference drops to zero.
+ *
+ * E.g. with a ref of one here:
+ * [  0  ][  0  ][  1  ][  0  ][  0  ][  0  ][  0  ][  0  ][  0  ]
+ *
+ * These nodes could be freed or recycled ("reaped"):
+ * [  0  ][  0  ]
+ *
+ * These must be preserved until the leading ref drops to zero:
+ *               [  1  ][  0  ][  0  ][  0  ][  0  ][  0  ][  0  ]
+ *
+ * When a query starts we take a reference on the current tail of
+ * the list, knowing that no already-buffered samples can possibly
+ * relate to the newly-started query. A pointer to this node is
+ * also saved in the query object's ->oa.samples_head.
+ *
+ * E.g. starting query A while there are two nodes in .sample_buffers:
+ *                ________________A________
+ *                |
+ *
+ * [  0  ][  1  ]
+ *           ^_______ Add a reference and store pointer to node in
+ *                    A->oa.samples_head
+ *
+ * Moving forward to when the B query starts with no new buffer nodes:
+ * (for reference, i915 perf reads() are only done when queries finish)
+ *                ________________A_______
+ *                | ________B___
+ *                | |
+ *
+ * [  0  ][  2  ]
+ *           ^_______ Add a reference and store pointer to
+ *                    node in B->oa.samples_head
+ *
+ * Once a query is finished, after an OA query has become 'Ready',
+ * once the End OA report has landed and after we we have processed
+ * all the intermediate periodic samples then we drop the
+ * ->oa.samples_head reference we took at the start.
+ *
+ * So when the B query has finished we have:
+ *                ________________A________
+ *                | ______B___________
+ *                | |                |
+ * [  0  ][  1  ][  0  ][  0  ][  0  ]
+ *           ^_______ Drop B->oa.samples_head reference
+ *
+ * We still can't free these due to the A->oa.samples_head ref:
+ *        [  1  ][  0  ][  0  ][  0  ]
+ *
+ * When the A query finishes: (note there's a new ref for C's samples_head)
+ *                ________________A_________________
+ *                |                                |
+ *                |                    _____C_________
+ *                |                    |           |
+ * [  0  ][  0  ][  0  ][  0  ][  1  ][  0  ][  0  ]
+ *           ^_______ Drop A->oa.samples_head reference
+ *
+ * And we can now reap these nodes up to the C->oa.samples_head:
+ * [  X  ][  X  ][  X  ][  X  ]
+ *                  keeping -> [  1  ][  0  ][  0  ]
+ *
+ * We reap old sample buffers each time we finish processing an OA
+ * query by iterating the sample_buffers list from the head until we
+ * find a referenced node and stop.
+ *
+ * Reaped buffers move to a perfquery.free_sample_buffers list and
+ * when we come to read() we first look to recycle a buffer from the
+ * free_sample_buffers list before allocating a new buffer.
+ */
+struct oa_sample_buf {
+   struct exec_node link;
+   int refcount;
+   int len;
+   uint8_t buf[I915_PERF_OA_SAMPLE_SIZE * 10];
+   uint32_t last_timestamp;
+};
+
+/**
+ * gen representation of a performance query object.
+ *
+ * NB: We want to keep this structure relatively lean considering that
+ * applications may expect to allocate enough objects to be able to
+ * query around all draw calls in a frame.
+ */
+struct gen_perf_query_object
+{
+   const struct gen_perf_query_info *queryinfo;
+
+   /* See query->kind to know which state below is in use... */
+   union {
+      struct {
+
+         /**
+          * BO containing OA counter snapshots at query Begin/End time.
+          */
+         void *bo;
+
+         /**
+          * Address of mapped of @bo
+          */
+         void *map;
+
+         /**
+          * The MI_REPORT_PERF_COUNT command lets us specify a unique
+          * ID that will be reflected in the resulting OA report
+          * that's written by the GPU. This is the ID we're expecting
+          * in the begin report and the the end report should be
+          * @begin_report_id + 1.
+          */
+         int begin_report_id;
+
+         /**
+          * Reference the head of the brw->perfquery.sample_buffers
+          * list at the time that the query started (so we only need
+          * to look at nodes after this point when looking for samples
+          * related to this query)
+          *
+          * (See struct brw_oa_sample_buf description for more details)
+          */
+         struct exec_node *samples_head;
+
+         /**
+          * false while in the unaccumulated_elements list, and set to
+          * true when the final, end MI_RPC snapshot has been
+          * accumulated.
+          */
+         bool results_accumulated;
+
+         /**
+          * Frequency of the GT at begin and end of the query.
+          */
+         uint64_t gt_frequency[2];
+
+         /**
+          * Accumulated OA results between begin and end of the query.
+          */
+         struct gen_perf_query_result result;
+      } oa;
+
+      struct {
+         /**
+          * BO containing starting and ending snapshots for the
+          * statistics counters.
+          */
+         void *bo;
+      } pipeline_stats;
+   };
+};
+
+struct gen_perf_context {
+   struct gen_perf_config *perf;
+
+   void * ctx;  /* driver context (eg, brw_context) */
+   void * bufmgr;
+   const struct gen_device_info *devinfo;
+
+   uint32_t hw_ctx;
+   int drm_fd;
+
+   /* The i915 perf stream we open to setup + enable the OA counters */
+   int oa_stream_fd;
+
+   /* An i915 perf stream fd gives exclusive access to the OA unit that will
+    * report counter snapshots for a specific counter set/profile in a
+    * specific layout/format so we can only start OA queries that are
+    * compatible with the currently open fd...
+    */
+   int current_oa_metrics_set_id;
+   int current_oa_format;
+
+   /* List of buffers containing OA reports */
+   struct exec_list sample_buffers;
+
+   /* Cached list of empty sample buffers */
+   struct exec_list free_sample_buffers;
+
+   int n_active_oa_queries;
+   int n_active_pipeline_stats_queries;
+
+   /* The number of queries depending on running OA counters which
+    * extends beyond brw_end_perf_query() since we need to wait until
+    * the last MI_RPC command has parsed by the GPU.
+    *
+    * Accurate accounting is important here as emitting an
+    * MI_REPORT_PERF_COUNT command while the OA unit is disabled will
+    * effectively hang the gpu.
+    */
+   int n_oa_users;
+
+   /* To help catch an spurious problem with the hardware or perf
+    * forwarding samples, we emit each MI_REPORT_PERF_COUNT command
+    * with a unique ID that we can explicitly check for...
+    */
+   int next_query_start_report_id;
+
+   /**
+    * An array of queries whose results haven't yet been assembled
+    * based on the data in buffer objects.
+    *
+    * These may be active, or have already ended.  However, the
+    * results have not been requested.
+    */
+   struct gen_perf_query_object **unaccumulated;
+   int unaccumulated_elements;
+   int unaccumulated_array_size;
+
+   /* The total number of query objects so we can relinquish
+    * our exclusive access to perf if the application deletes
+    * all of its objects. (NB: We only disable perf while
+    * there are no active queries)
+    */
+   int n_query_instances;
+};
+
+static bool
+inc_n_users(struct gen_perf_context *perf_ctx)
+{
+   if (perf_ctx->n_oa_users == 0 &&
+       gen_ioctl(perf_ctx->oa_stream_fd, I915_PERF_IOCTL_ENABLE, 0) < 0)
+   {
+      return false;
+   }
+   ++perf_ctx->n_oa_users;
+
+   return true;
+}
+
+static void
+dec_n_users(struct gen_perf_context *perf_ctx)
+{
+   /* Disabling the i915 perf stream will effectively disable the OA
+    * counters.  Note it's important to be sure there are no outstanding
+    * MI_RPC commands at this point since they could stall the CS
+    * indefinitely once OACONTROL is disabled.
+    */
+   --perf_ctx->n_oa_users;
+   if (perf_ctx->n_oa_users == 0 &&
+       gen_ioctl(perf_ctx->oa_stream_fd, I915_PERF_IOCTL_DISABLE, 0) < 0)
+   {
+      DBG("WARNING: Error disabling gen perf stream: %m\n");
+   }
+}
+
+static void
+gen_perf_close(struct gen_perf_context *perfquery,
+               const struct gen_perf_query_info *query)
+{
+   if (perfquery->oa_stream_fd != -1) {
+      close(perfquery->oa_stream_fd);
+      perfquery->oa_stream_fd = -1;
+   }
+   if (query->kind == GEN_PERF_QUERY_TYPE_RAW) {
+      struct gen_perf_query_info *raw_query =
+         (struct gen_perf_query_info *) query;
+      raw_query->oa_metrics_set_id = 0;
+   }
+}
+
+static bool
+gen_perf_open(struct gen_perf_context *perf_ctx,
+              int metrics_set_id,
+              int report_format,
+              int period_exponent,
+              int drm_fd,
+              uint32_t ctx_id)
+{
+   uint64_t properties[] = {
+      /* Single context sampling */
+      DRM_I915_PERF_PROP_CTX_HANDLE, ctx_id,
+
+      /* Include OA reports in samples */
+      DRM_I915_PERF_PROP_SAMPLE_OA, true,
+
+      /* OA unit configuration */
+      DRM_I915_PERF_PROP_OA_METRICS_SET, metrics_set_id,
+      DRM_I915_PERF_PROP_OA_FORMAT, report_format,
+      DRM_I915_PERF_PROP_OA_EXPONENT, period_exponent,
+   };
+   struct drm_i915_perf_open_param param = {
+      .flags = I915_PERF_FLAG_FD_CLOEXEC |
+               I915_PERF_FLAG_FD_NONBLOCK |
+               I915_PERF_FLAG_DISABLED,
+      .num_properties = ARRAY_SIZE(properties) / 2,
+      .properties_ptr = (uintptr_t) properties,
+   };
+   int fd = gen_ioctl(drm_fd, DRM_IOCTL_I915_PERF_OPEN, &param);
+   if (fd == -1) {
+      DBG("Error opening gen perf OA stream: %m\n");
+      return false;
+   }
+
+   perf_ctx->oa_stream_fd = fd;
+
+   perf_ctx->current_oa_metrics_set_id = metrics_set_id;
+   perf_ctx->current_oa_format = report_format;
+
+   return true;
+}
+
+static uint64_t
+get_metric_id(struct gen_perf_config *perf,
+              const struct gen_perf_query_info *query)
+{
+   /* These queries are know not to ever change, their config ID has been
+    * loaded upon the first query creation. No need to look them up again.
+    */
+   if (query->kind == GEN_PERF_QUERY_TYPE_OA)
+      return query->oa_metrics_set_id;
+
+   assert(query->kind == GEN_PERF_QUERY_TYPE_RAW);
+
+   /* Raw queries can be reprogrammed up by an external application/library.
+    * When a raw query is used for the first time it's id is set to a value !=
+    * 0. When it stops being used the id returns to 0. No need to reload the
+    * ID when it's already loaded.
+    */
+   if (query->oa_metrics_set_id != 0) {
+      DBG("Raw query '%s' guid=%s using cached ID: %"PRIu64"\n",
+          query->name, query->guid, query->oa_metrics_set_id);
+      return query->oa_metrics_set_id;
+   }
+
+   struct gen_perf_query_info *raw_query = (struct gen_perf_query_info *)query;
+   if (!gen_perf_load_metric_id(perf, query->guid,
+                                &raw_query->oa_metrics_set_id)) {
+      DBG("Unable to read query guid=%s ID, falling back to test config\n", query->guid);
+      raw_query->oa_metrics_set_id = 1ULL;
+   } else {
+      DBG("Raw query '%s'guid=%s loaded ID: %"PRIu64"\n",
+          query->name, query->guid, query->oa_metrics_set_id);
+   }
+   return query->oa_metrics_set_id;
+}
+
+static struct oa_sample_buf *
+get_free_sample_buf(struct gen_perf_context *perf_ctx)
+{
+   struct exec_node *node = exec_list_pop_head(&perf_ctx->free_sample_buffers);
+   struct oa_sample_buf *buf;
+
+   if (node)
+      buf = exec_node_data(struct oa_sample_buf, node, link);
+   else {
+      buf = ralloc_size(perf_ctx->perf, sizeof(*buf));
+
+      exec_node_init(&buf->link);
+      buf->refcount = 0;
+   }
+   buf->len = 0;
+
+   return buf;
+}
+
+static void
+reap_old_sample_buffers(struct gen_perf_context *perf_ctx)
+{
+   struct exec_node *tail_node =
+      exec_list_get_tail(&perf_ctx->sample_buffers);
+   struct oa_sample_buf *tail_buf =
+      exec_node_data(struct oa_sample_buf, tail_node, link);
+
+   /* Remove all old, unreferenced sample buffers walking forward from
+    * the head of the list, except always leave at least one node in
+    * the list so we always have a node to reference when we Begin
+    * a new query.
+    */
+   foreach_list_typed_safe(struct oa_sample_buf, buf, link,
+                           &perf_ctx->sample_buffers)
+   {
+      if (buf->refcount == 0 && buf != tail_buf) {
+         exec_node_remove(&buf->link);
+         exec_list_push_head(&perf_ctx->free_sample_buffers, &buf->link);
+      } else
+         return;
+   }
+}
+
+static void
+free_sample_bufs(struct gen_perf_context *perf_ctx)
+{
+   foreach_list_typed_safe(struct oa_sample_buf, buf, link,
+                           &perf_ctx->free_sample_buffers)
+      ralloc_free(buf);
+
+   exec_list_make_empty(&perf_ctx->free_sample_buffers);
+}
+
+
+struct gen_perf_query_object *
+gen_perf_new_query(struct gen_perf_context *perf_ctx, unsigned query_index)
+{
+   const struct gen_perf_query_info *query =
+      &perf_ctx->perf->queries[query_index];
+   struct gen_perf_query_object *obj =
+      calloc(1, sizeof(struct gen_perf_query_object));
+
+   if (!obj)
+      return NULL;
+
+   obj->queryinfo = query;
+
+   perf_ctx->n_query_instances++;
+   return obj;
+}
+
+int
+gen_perf_active_queries(struct gen_perf_context *perf_ctx,
+                        const struct gen_perf_query_info *query)
+{
+   assert(perf_ctx->n_active_oa_queries == 0 || perf_ctx->n_active_pipeline_stats_queries == 0);
+
+   switch (query->kind) {
+   case GEN_PERF_QUERY_TYPE_OA:
+   case GEN_PERF_QUERY_TYPE_RAW:
+      return perf_ctx->n_active_oa_queries;
+      break;
+
+   case GEN_PERF_QUERY_TYPE_PIPELINE:
+      return perf_ctx->n_active_pipeline_stats_queries;
+      break;
+
+   default:
+      unreachable("Unknown query type");
+      break;
+   }
+}
+
+const struct gen_perf_query_info*
+gen_perf_query_info(const struct gen_perf_query_object *query)
+{
+   return query->queryinfo;
+}
+
+struct gen_perf_context *
+gen_perf_new_context(void *parent)
+{
+   struct gen_perf_context *ctx = rzalloc(parent, struct gen_perf_context);
+   if (! ctx)
+      fprintf(stderr, "%s: failed to alloc context\n", __func__);
+   return ctx;
+}
+
+struct gen_perf_config *
+gen_perf_config(struct gen_perf_context *ctx)
+{
+   return ctx->perf;
+}
+
+void
+gen_perf_init_context(struct gen_perf_context *perf_ctx,
+                      struct gen_perf_config *perf_cfg,
+                      void * ctx,  /* driver context (eg, brw_context) */
+                      void * bufmgr,  /* eg brw_bufmgr */
+                      const struct gen_device_info *devinfo,
+                      uint32_t hw_ctx,
+                      int drm_fd)
+{
+   perf_ctx->perf = perf_cfg;
+   perf_ctx->ctx = ctx;
+   perf_ctx->bufmgr = bufmgr;
+   perf_ctx->drm_fd = drm_fd;
+   perf_ctx->hw_ctx = hw_ctx;
+   perf_ctx->devinfo = devinfo;
+
+   perf_ctx->unaccumulated =
+      ralloc_array(ctx, struct gen_perf_query_object *, 2);
+   perf_ctx->unaccumulated_elements = 0;
+   perf_ctx->unaccumulated_array_size = 2;
+
+   exec_list_make_empty(&perf_ctx->sample_buffers);
+   exec_list_make_empty(&perf_ctx->free_sample_buffers);
+
+   /* It's convenient to guarantee that this linked list of sample
+    * buffers is never empty so we add an empty head so when we
+    * Begin an OA query we can always take a reference on a buffer
+    * in this list.
+    */
+   struct oa_sample_buf *buf = get_free_sample_buf(perf_ctx);
+   exec_list_push_head(&perf_ctx->sample_buffers, &buf->link);
+
+   perf_ctx->oa_stream_fd = -1;
+   perf_ctx->next_query_start_report_id = 1000;
+}
+
+/**
+ * Add a query to the global list of "unaccumulated queries."
+ *
+ * Queries are tracked here until all the associated OA reports have
+ * been accumulated via accumulate_oa_reports() after the end
+ * MI_REPORT_PERF_COUNT has landed in query->oa.bo.
+ */
+static void
+add_to_unaccumulated_query_list(struct gen_perf_context *perf_ctx,
+                                struct gen_perf_query_object *obj)
+{
+   if (perf_ctx->unaccumulated_elements >=
+       perf_ctx->unaccumulated_array_size)
+   {
+      perf_ctx->unaccumulated_array_size *= 1.5;
+      perf_ctx->unaccumulated =
+         reralloc(perf_ctx->ctx, perf_ctx->unaccumulated,
+                  struct gen_perf_query_object *,
+                  perf_ctx->unaccumulated_array_size);
+   }
+
+   perf_ctx->unaccumulated[perf_ctx->unaccumulated_elements++] = obj;
+}
+
+/**
+ * Emit MI_STORE_REGISTER_MEM commands to capture all of the
+ * pipeline statistics for the performance query object.
+ */
+static void
+snapshot_statistics_registers(struct gen_perf_context *ctx,
+                              struct gen_perf_query_object *obj,
+                              uint32_t offset_in_bytes)
+{
+   struct gen_perf_config *perf = ctx->perf;
+   const struct gen_perf_query_info *query = obj->queryinfo;
+   const int n_counters = query->n_counters;
+
+   for (int i = 0; i < n_counters; i++) {
+      const struct gen_perf_query_counter *counter = &query->counters[i];
+
+      assert(counter->data_type == GEN_PERF_COUNTER_DATA_TYPE_UINT64);
+
+      perf->vtbl.store_register_mem(ctx->ctx, obj->pipeline_stats.bo,
+                                    counter->pipeline_stat.reg, 8,
+                                    offset_in_bytes + i * sizeof(uint64_t));
+   }
+}
+
+static void
+snapshot_freq_register(struct gen_perf_context *ctx,
+                       struct gen_perf_query_object *query,
+                       uint32_t bo_offset)
+{
+   struct gen_perf_config *perf = ctx->perf;
+   const struct gen_device_info *devinfo = ctx->devinfo;
+
+   if (devinfo->gen == 8 && !devinfo->is_cherryview)
+      perf->vtbl.store_register_mem(ctx->ctx, query->oa.bo, GEN7_RPSTAT1, 4, bo_offset);
+   else if (devinfo->gen >= 9)
+      perf->vtbl.store_register_mem(ctx->ctx, query->oa.bo, GEN9_RPSTAT0, 4, bo_offset);
+}
+
+bool
+gen_perf_begin_query(struct gen_perf_context *perf_ctx,
+                     struct gen_perf_query_object *query)
+{
+   struct gen_perf_config *perf_cfg = perf_ctx->perf;
+   const struct gen_perf_query_info *queryinfo = query->queryinfo;
+
+   /* XXX: We have to consider that the command parser unit that parses batch
+    * buffer commands and is used to capture begin/end counter snapshots isn't
+    * implicitly synchronized with what's currently running across other GPU
+    * units (such as the EUs running shaders) that the performance counters are
+    * associated with.
+    *
+    * The intention of performance queries is to measure the work associated
+    * with commands between the begin/end delimiters and so for that to be the
+    * case we need to explicitly synchronize the parsing of commands to capture
+    * Begin/End counter snapshots with what's running across other parts of the
+    * GPU.
+    *
+    * When the command parser reaches a Begin marker it effectively needs to
+    * drain everything currently running on the GPU until the hardware is idle
+    * before capturing the first snapshot of counters - otherwise the results
+    * would also be measuring the effects of earlier commands.
+    *
+    * When the command parser reaches an End marker it needs to stall until
+    * everything currently running on the GPU has finished before capturing the
+    * end snapshot - otherwise the results won't be a complete representation
+    * of the work.
+    *
+    * To achieve this, we stall the pipeline at pixel scoreboard (prevent any
+    * additional work to be processed by the pipeline until all pixels of the
+    * previous draw has be completed).
+    *
+    * N.B. The final results are based on deltas of counters between (inside)
+    * Begin/End markers so even though the total wall clock time of the
+    * workload is stretched by larger pipeline bubbles the bubbles themselves
+    * are generally invisible to the query results. Whether that's a good or a
+    * bad thing depends on the use case. For a lower real-time impact while
+    * capturing metrics then periodic sampling may be a better choice than
+    * INTEL_performance_query.
+    *
+    *
+    * This is our Begin synchronization point to drain current work on the
+    * GPU before we capture our first counter snapshot...
+    */
+   perf_cfg->vtbl.emit_stall_at_pixel_scoreboard(perf_ctx->ctx);
+
+   switch (queryinfo->kind) {
+   case GEN_PERF_QUERY_TYPE_OA:
+   case GEN_PERF_QUERY_TYPE_RAW: {
+
+      /* Opening an i915 perf stream implies exclusive access to the OA unit
+       * which will generate counter reports for a specific counter set with a
+       * specific layout/format so we can't begin any OA based queries that
+       * require a different counter set or format unless we get an opportunity
+       * to close the stream and open a new one...
+       */
+      uint64_t metric_id = get_metric_id(perf_ctx->perf, queryinfo);
+
+      if (perf_ctx->oa_stream_fd != -1 &&
+          perf_ctx->current_oa_metrics_set_id != metric_id) {
+
+         if (perf_ctx->n_oa_users != 0) {
+            DBG("WARNING: Begin failed already using perf config=%i/%"PRIu64"\n",
+                perf_ctx->current_oa_metrics_set_id, metric_id);
+            return false;
+         } else
+            gen_perf_close(perf_ctx, queryinfo);
+      }
+
+      /* If the OA counters aren't already on, enable them. */
+      if (perf_ctx->oa_stream_fd == -1) {
+         const struct gen_device_info *devinfo = perf_ctx->devinfo;
+
+         /* The period_exponent gives a sampling period as follows:
+          *   sample_period = timestamp_period * 2^(period_exponent + 1)
+          *
+          * The timestamps increments every 80ns (HSW), ~52ns (GEN9LP) or
+          * ~83ns (GEN8/9).
+          *
+          * The counter overflow period is derived from the EuActive counter
+          * which reads a counter that increments by the number of clock
+          * cycles multiplied by the number of EUs. It can be calculated as:
+          *
+          * 2^(number of bits in A counter) / (n_eus * max_gen_freq * 2)
+          *
+          * (E.g. 40 EUs @ 1GHz = ~53ms)
+          *
+          * We select a sampling period inferior to that overflow period to
+          * ensure we cannot see more than 1 counter overflow, otherwise we
+          * could loose information.
+          */
+
+         int a_counter_in_bits = 32;
+         if (devinfo->gen >= 8)
+            a_counter_in_bits = 40;
+
+         uint64_t overflow_period = pow(2, a_counter_in_bits) / (perf_cfg->sys_vars.n_eus *
+             /* drop 1GHz freq to have units in nanoseconds */
+             2);
+
+         DBG("A counter overflow period: %"PRIu64"ns, %"PRIu64"ms (n_eus=%"PRIu64")\n",
+             overflow_period, overflow_period / 1000000ul, perf_cfg->sys_vars.n_eus);
+
+         int period_exponent = 0;
+         uint64_t prev_sample_period, next_sample_period;
+         for (int e = 0; e < 30; e++) {
+            prev_sample_period = 1000000000ull * pow(2, e + 1) / devinfo->timestamp_frequency;
+            next_sample_period = 1000000000ull * pow(2, e + 2) / devinfo->timestamp_frequency;
+
+            /* Take the previous sampling period, lower than the overflow
+             * period.
+             */
+            if (prev_sample_period < overflow_period &&
+                next_sample_period > overflow_period)
+               period_exponent = e + 1;
+         }
+
+         if (period_exponent == 0) {
+            DBG("WARNING: enable to find a sampling exponent\n");
+            return false;
+         }
+
+         DBG("OA sampling exponent: %i ~= %"PRIu64"ms\n", period_exponent,
+             prev_sample_period / 1000000ul);
+
+         if (!gen_perf_open(perf_ctx, metric_id, queryinfo->oa_format,
+                            period_exponent, perf_ctx->drm_fd,
+                            perf_ctx->hw_ctx))
+            return false;
+      } else {
+         assert(perf_ctx->current_oa_metrics_set_id == metric_id &&
+                perf_ctx->current_oa_format == queryinfo->oa_format);
+      }
+
+      if (!inc_n_users(perf_ctx)) {
+         DBG("WARNING: Error enabling i915 perf stream: %m\n");
+         return false;
+      }
+
+      if (query->oa.bo) {
+         perf_cfg->vtbl.bo_unreference(query->oa.bo);
+         query->oa.bo = NULL;
+      }
+
+      query->oa.bo = perf_cfg->vtbl.bo_alloc(perf_ctx->bufmgr,
+                                             "perf. query OA MI_RPC bo",
+                                             MI_RPC_BO_SIZE);
+#ifdef DEBUG
+      /* Pre-filling the BO helps debug whether writes landed. */
+      void *map = perf_cfg->vtbl.bo_map(perf_ctx->ctx, query->oa.bo, MAP_WRITE);
+      memset(map, 0x80, MI_RPC_BO_SIZE);
+      perf_cfg->vtbl.bo_unmap(query->oa.bo);
+#endif
+
+      query->oa.begin_report_id = perf_ctx->next_query_start_report_id;
+      perf_ctx->next_query_start_report_id += 2;
+
+      /* Take a starting OA counter snapshot. */
+      perf_cfg->vtbl.emit_mi_report_perf_count(perf_ctx->ctx, query->oa.bo, 0,
+                                               query->oa.begin_report_id);
+      snapshot_freq_register(perf_ctx, query, MI_FREQ_START_OFFSET_BYTES);
+
+      ++perf_ctx->n_active_oa_queries;
+
+      /* No already-buffered samples can possibly be associated with this query
+       * so create a marker within the list of sample buffers enabling us to
+       * easily ignore earlier samples when processing this query after
+       * completion.
+       */
+      assert(!exec_list_is_empty(&perf_ctx->sample_buffers));
+      query->oa.samples_head = exec_list_get_tail(&perf_ctx->sample_buffers);
+
+      struct oa_sample_buf *buf =
+         exec_node_data(struct oa_sample_buf, query->oa.samples_head, link);
+
+      /* This reference will ensure that future/following sample
+       * buffers (that may relate to this query) can't be freed until
+       * this drops to zero.
+       */
+      buf->refcount++;
+
+      gen_perf_query_result_clear(&query->oa.result);
+      query->oa.results_accumulated = false;
+
+      add_to_unaccumulated_query_list(perf_ctx, query);
+      break;
+   }
+
+   case GEN_PERF_QUERY_TYPE_PIPELINE:
+      if (query->pipeline_stats.bo) {
+         perf_cfg->vtbl.bo_unreference(query->pipeline_stats.bo);
+         query->pipeline_stats.bo = NULL;
+      }
+
+      query->pipeline_stats.bo =
+         perf_cfg->vtbl.bo_alloc(perf_ctx->bufmgr,
+                                 "perf. query pipeline stats bo",
+                                 STATS_BO_SIZE);
+
+      /* Take starting snapshots. */
+      snapshot_statistics_registers(perf_ctx, query, 0);
+
+      ++perf_ctx->n_active_pipeline_stats_queries;
+      break;
+
+   default:
+      unreachable("Unknown query type");
+      break;
+   }
+
+   return true;
+}
+
+void
+gen_perf_end_query(struct gen_perf_context *perf_ctx,
+                   struct gen_perf_query_object *query)
+{
+   struct gen_perf_config *perf_cfg = perf_ctx->perf;
+
+   /* Ensure that the work associated with the queried commands will have
+    * finished before taking our query end counter readings.
+    *
+    * For more details see comment in brw_begin_perf_query for
+    * corresponding flush.
+    */
+   perf_cfg->vtbl.emit_stall_at_pixel_scoreboard(perf_ctx->ctx);
+
+   switch (query->queryinfo->kind) {
+   case GEN_PERF_QUERY_TYPE_OA:
+   case GEN_PERF_QUERY_TYPE_RAW:
+
+      /* NB: It's possible that the query will have already been marked
+       * as 'accumulated' if an error was seen while reading samples
+       * from perf. In this case we mustn't try and emit a closing
+       * MI_RPC command in case the OA unit has already been disabled
+       */
+      if (!query->oa.results_accumulated) {
+         /* Take an ending OA counter snapshot. */
+         snapshot_freq_register(perf_ctx, query, MI_FREQ_END_OFFSET_BYTES);
+         perf_cfg->vtbl.emit_mi_report_perf_count(perf_ctx->ctx, query->oa.bo,
+                                             MI_RPC_BO_END_OFFSET_BYTES,
+                                             query->oa.begin_report_id + 1);
+      }
+
+      --perf_ctx->n_active_oa_queries;
+
+      /* NB: even though the query has now ended, it can't be accumulated
+       * until the end MI_REPORT_PERF_COUNT snapshot has been written
+       * to query->oa.bo
+       */
+      break;
+
+   case GEN_PERF_QUERY_TYPE_PIPELINE:
+      snapshot_statistics_registers(perf_ctx, query,
+                                    STATS_BO_END_OFFSET_BYTES);
+      --perf_ctx->n_active_pipeline_stats_queries;
+      break;
+
+   default:
+      unreachable("Unknown query type");
+      break;
+   }
+}
+
+enum OaReadStatus {
+   OA_READ_STATUS_ERROR,
+   OA_READ_STATUS_UNFINISHED,
+   OA_READ_STATUS_FINISHED,
+};
+
+static enum OaReadStatus
+read_oa_samples_until(struct gen_perf_context *perf_ctx,
+                      uint32_t start_timestamp,
+                      uint32_t end_timestamp)
+{
+   struct exec_node *tail_node =
+      exec_list_get_tail(&perf_ctx->sample_buffers);
+   struct oa_sample_buf *tail_buf =
+      exec_node_data(struct oa_sample_buf, tail_node, link);
+   uint32_t last_timestamp =
+      tail_buf->len == 0 ? start_timestamp : tail_buf->last_timestamp;
+
+   while (1) {
+      struct oa_sample_buf *buf = get_free_sample_buf(perf_ctx);
+      uint32_t offset;
+      int len;
+
+      while ((len = read(perf_ctx->oa_stream_fd, buf->buf,
+                         sizeof(buf->buf))) < 0 && errno == EINTR)
+         ;
+
+      if (len <= 0) {
+         exec_list_push_tail(&perf_ctx->free_sample_buffers, &buf->link);
+
+         if (len < 0) {
+            if (errno == EAGAIN) {
+               return ((last_timestamp - start_timestamp) < INT32_MAX &&
+                       (last_timestamp - start_timestamp) >=
+                       (end_timestamp - start_timestamp)) ?
+                      OA_READ_STATUS_FINISHED :
+                      OA_READ_STATUS_UNFINISHED;
+            } else {
+               DBG("Error reading i915 perf samples: %m\n");
+            }
+         } else
+            DBG("Spurious EOF reading i915 perf samples\n");
+
+         return OA_READ_STATUS_ERROR;
+      }
+
+      buf->len = len;
+      exec_list_push_tail(&perf_ctx->sample_buffers, &buf->link);
+
+      /* Go through the reports and update the last timestamp. */
+      offset = 0;
+      while (offset < buf->len) {
+         const struct drm_i915_perf_record_header *header =
+            (const struct drm_i915_perf_record_header *) &buf->buf[offset];
+         uint32_t *report = (uint32_t *) (header + 1);
+
+         if (header->type == DRM_I915_PERF_RECORD_SAMPLE)
+            last_timestamp = report[1];
+
+         offset += header->size;
+      }
+
+      buf->last_timestamp = last_timestamp;
+   }
+
+   unreachable("not reached");
+   return OA_READ_STATUS_ERROR;
+}
+
+/**
+ * Try to read all the reports until either the delimiting timestamp
+ * or an error arises.
+ */
+static bool
+read_oa_samples_for_query(struct gen_perf_context *perf_ctx,
+                          struct gen_perf_query_object *query,
+                          void *current_batch)
+{
+   uint32_t *start;
+   uint32_t *last;
+   uint32_t *end;
+   struct gen_perf_config *perf_cfg = perf_ctx->perf;
+
+   /* We need the MI_REPORT_PERF_COUNT to land before we can start
+    * accumulate. */
+   assert(!perf_cfg->vtbl.batch_references(current_batch, query->oa.bo) &&
+          !perf_cfg->vtbl.bo_busy(query->oa.bo));
+
+   /* Map the BO once here and let accumulate_oa_reports() unmap
+    * it. */
+   if (query->oa.map == NULL)
+      query->oa.map = perf_cfg->vtbl.bo_map(perf_ctx->ctx, query->oa.bo, MAP_READ);
+
+   start = last = query->oa.map;
+   end = query->oa.map + MI_RPC_BO_END_OFFSET_BYTES;
+
+   if (start[0] != query->oa.begin_report_id) {
+      DBG("Spurious start report id=%"PRIu32"\n", start[0]);
+      return true;
+   }
+   if (end[0] != (query->oa.begin_report_id + 1)) {
+      DBG("Spurious end report id=%"PRIu32"\n", end[0]);
+      return true;
+   }
+
+   /* Read the reports until the end timestamp. */
+   switch (read_oa_samples_until(perf_ctx, start[1], end[1])) {
+   case OA_READ_STATUS_ERROR:
+      /* Fallthrough and let accumulate_oa_reports() deal with the
+       * error. */
+   case OA_READ_STATUS_FINISHED:
+      return true;
+   case OA_READ_STATUS_UNFINISHED:
+      return false;
+   }
+
+   unreachable("invalid read status");
+   return false;
+}
+
+void
+gen_perf_wait_query(struct gen_perf_context *perf_ctx,
+                    struct gen_perf_query_object *query,
+                    void *current_batch)
+{
+   struct gen_perf_config *perf_cfg = perf_ctx->perf;
+   struct brw_bo *bo = NULL;
+
+   switch (query->queryinfo->kind) {
+   case GEN_PERF_QUERY_TYPE_OA:
+   case GEN_PERF_QUERY_TYPE_RAW:
+      bo = query->oa.bo;
+      break;
+
+   case GEN_PERF_QUERY_TYPE_PIPELINE:
+      bo = query->pipeline_stats.bo;
+      break;
+
+   default:
+      unreachable("Unknown query type");
+      break;
+   }
+
+   if (bo == NULL)
+      return;
+
+   /* If the current batch references our results bo then we need to
+    * flush first...
+    */
+   if (perf_cfg->vtbl.batch_references(current_batch, bo))
+      perf_cfg->vtbl.batchbuffer_flush(perf_ctx->ctx, __FILE__, __LINE__);
+
+   perf_cfg->vtbl.bo_wait_rendering(bo);
+
+   /* Due to a race condition between the OA unit signaling report
+    * availability and the report actually being written into memory,
+    * we need to wait for all the reports to come in before we can
+    * read them.
+    */
+   if (query->queryinfo->kind == GEN_PERF_QUERY_TYPE_OA ||
+       query->queryinfo->kind == GEN_PERF_QUERY_TYPE_RAW) {
+      while (!read_oa_samples_for_query(perf_ctx, query, current_batch))
+         ;
+   }
+}
+
+bool
+gen_perf_is_query_ready(struct gen_perf_context *perf_ctx,
+                        struct gen_perf_query_object *query,
+                        void *current_batch)
+{
+   struct gen_perf_config *perf_cfg = perf_ctx->perf;
+
+   switch (query->queryinfo->kind) {
+   case GEN_PERF_QUERY_TYPE_OA:
+   case GEN_PERF_QUERY_TYPE_RAW:
+      return (query->oa.results_accumulated ||
+              (query->oa.bo &&
+               !perf_cfg->vtbl.batch_references(current_batch, query->oa.bo) &&
+               !perf_cfg->vtbl.bo_busy(query->oa.bo) &&
+               read_oa_samples_for_query(perf_ctx, query, current_batch)));
+   case GEN_PERF_QUERY_TYPE_PIPELINE:
+      return (query->pipeline_stats.bo &&
+              !perf_cfg->vtbl.batch_references(current_batch, query->pipeline_stats.bo) &&
+              !perf_cfg->vtbl.bo_busy(query->pipeline_stats.bo));
+
+   default:
+      unreachable("Unknown query type");
+      break;
+   }
+
+   return false;
+}
+
+/**
+ * Remove a query from the global list of unaccumulated queries once
+ * after successfully accumulating the OA reports associated with the
+ * query in accumulate_oa_reports() or when discarding unwanted query
+ * results.
+ */
+static void
+drop_from_unaccumulated_query_list(struct gen_perf_context *perf_ctx,
+                                   struct gen_perf_query_object *query)
+{
+   for (int i = 0; i < perf_ctx->unaccumulated_elements; i++) {
+      if (perf_ctx->unaccumulated[i] == query) {
+         int last_elt = --perf_ctx->unaccumulated_elements;
+
+         if (i == last_elt)
+            perf_ctx->unaccumulated[i] = NULL;
+         else {
+            perf_ctx->unaccumulated[i] =
+               perf_ctx->unaccumulated[last_elt];
+         }
+
+         break;
+      }
+   }
+
+   /* Drop our samples_head reference so that associated periodic
+    * sample data buffers can potentially be reaped if they aren't
+    * referenced by any other queries...
+    */
+
+   struct oa_sample_buf *buf =
+      exec_node_data(struct oa_sample_buf, query->oa.samples_head, link);
+
+   assert(buf->refcount > 0);
+   buf->refcount--;
+
+   query->oa.samples_head = NULL;
+
+   reap_old_sample_buffers(perf_ctx);
+}
+
+/* In general if we see anything spurious while accumulating results,
+ * we don't try and continue accumulating the current query, hoping
+ * for the best, we scrap anything outstanding, and then hope for the
+ * best with new queries.
+ */
+static void
+discard_all_queries(struct gen_perf_context *perf_ctx)
+{
+   while (perf_ctx->unaccumulated_elements) {
+      struct gen_perf_query_object *query = perf_ctx->unaccumulated[0];
+
+      query->oa.results_accumulated = true;
+      drop_from_unaccumulated_query_list(perf_ctx, query);
+
+      dec_n_users(perf_ctx);
+   }
+}
+
+/* Looks for the validity bit of context ID (dword 2) of an OA report. */
+static bool
+oa_report_ctx_id_valid(const struct gen_device_info *devinfo,
+                       const uint32_t *report)
+{
+   assert(devinfo->gen >= 8);
+   if (devinfo->gen == 8)
+      return (report[0] & (1 << 25)) != 0;
+   return (report[0] & (1 << 16)) != 0;
+}
+
+/**
+ * Accumulate raw OA counter values based on deltas between pairs of
+ * OA reports.
+ *
+ * Accumulation starts from the first report captured via
+ * MI_REPORT_PERF_COUNT (MI_RPC) by brw_begin_perf_query() until the
+ * last MI_RPC report requested by brw_end_perf_query(). Between these
+ * two reports there may also some number of periodically sampled OA
+ * reports collected via the i915 perf interface - depending on the
+ * duration of the query.
+ *
+ * These periodic snapshots help to ensure we handle counter overflow
+ * correctly by being frequent enough to ensure we don't miss multiple
+ * overflows of a counter between snapshots. For Gen8+ the i915 perf
+ * snapshots provide the extra context-switch reports that let us
+ * subtract out the progress of counters associated with other
+ * contexts running on the system.
+ */
+static void
+accumulate_oa_reports(struct gen_perf_context *perf_ctx,
+                      struct gen_perf_query_object *query)
+{
+   const struct gen_device_info *devinfo = perf_ctx->devinfo;
+   uint32_t *start;
+   uint32_t *last;
+   uint32_t *end;
+   struct exec_node *first_samples_node;
+   bool last_report_ctx_match = true;
+   int out_duration = 0;
+
+   assert(query->oa.map != NULL);
+
+   start = last = query->oa.map;
+   end = query->oa.map + MI_RPC_BO_END_OFFSET_BYTES;
+
+   if (start[0] != query->oa.begin_report_id) {
+      DBG("Spurious start report id=%"PRIu32"\n", start[0]);
+      goto error;
+   }
+   if (end[0] != (query->oa.begin_report_id + 1)) {
+      DBG("Spurious end report id=%"PRIu32"\n", end[0]);
+      goto error;
+   }
+
+   /* On Gen12+ OA reports are sourced from per context counters, so we don't
+    * ever have to look at the global OA buffer. Yey \o/
+    */
+   if (perf_ctx->devinfo->gen >= 12) {
+      last = start;
+      goto end;
+   }
+
+   /* See if we have any periodic reports to accumulate too... */
+
+   /* N.B. The oa.samples_head was set when the query began and
+    * pointed to the tail of the perf_ctx->sample_buffers list at
+    * the time the query started. Since the buffer existed before the
+    * first MI_REPORT_PERF_COUNT command was emitted we therefore know
+    * that no data in this particular node's buffer can possibly be
+    * associated with the query - so skip ahead one...
+    */
+   first_samples_node = query->oa.samples_head->next;
+
+   foreach_list_typed_from(struct oa_sample_buf, buf, link,
+                           &perf_ctx->sample_buffers,
+                           first_samples_node)
+   {
+      int offset = 0;
+
+      while (offset < buf->len) {
+         const struct drm_i915_perf_record_header *header =
+            (const struct drm_i915_perf_record_header *)(buf->buf + offset);
+
+         assert(header->size != 0);
+         assert(header->size <= buf->len);
+
+         offset += header->size;
+
+         switch (header->type) {
+         case DRM_I915_PERF_RECORD_SAMPLE: {
+            uint32_t *report = (uint32_t *)(header + 1);
+            bool report_ctx_match = true;
+            bool add = true;
+
+            /* Ignore reports that come before the start marker.
+             * (Note: takes care to allow overflow of 32bit timestamps)
+             */
+            if (gen_device_info_timebase_scale(devinfo,
+                                               report[1] - start[1]) > 5000000000) {
+               continue;
+            }
+
+            /* Ignore reports that come after the end marker.
+             * (Note: takes care to allow overflow of 32bit timestamps)
+             */
+            if (gen_device_info_timebase_scale(devinfo,
+                                               report[1] - end[1]) <= 5000000000) {
+               goto end;
+            }
+
+            /* For Gen8+ since the counters continue while other
+             * contexts are running we need to discount any unrelated
+             * deltas. The hardware automatically generates a report
+             * on context switch which gives us a new reference point
+             * to continuing adding deltas from.
+             *
+             * For Haswell we can rely on the HW to stop the progress
+             * of OA counters while any other context is acctive.
+             */
+            if (devinfo->gen >= 8) {
+               /* Consider that the current report matches our context only if
+                * the report says the report ID is valid.
+                */
+               report_ctx_match = oa_report_ctx_id_valid(devinfo, report) &&
+                  report[2] == start[2];
+               if (report_ctx_match)
+                  out_duration = 0;
+               else
+                  out_duration++;
+
+               /* Only add the delta between <last, report> if the last report
+                * was clearly identified as our context, or if we have at most
+                * 1 report without a matching ID.
+                *
+                * The OA unit will sometimes label reports with an invalid
+                * context ID when i915 rewrites the execlist submit register
+                * with the same context as the one currently running. This
+                * happens when i915 wants to notify the HW of ringbuffer tail
+                * register update. We have to consider this report as part of
+                * our context as the 3d pipeline behind the OACS unit is still
+                * processing the operations started at the previous execlist
+                * submission.
+                */
+               add = last_report_ctx_match && out_duration < 2;
+            }
+
+            if (add) {
+               gen_perf_query_result_accumulate(&query->oa.result,
+                                                query->queryinfo,
+                                                last, report);
+            } else {
+               /* We're not adding the delta because we've identified it's not
+                * for the context we filter for. We can consider that the
+                * query was split.
+                */
+               query->oa.result.query_disjoint = true;
+            }
+
+            last = report;
+            last_report_ctx_match = report_ctx_match;
+
+            break;
+         }
+
+         case DRM_I915_PERF_RECORD_OA_BUFFER_LOST:
+             DBG("i915 perf: OA error: all reports lost\n");
+             goto error;
+         case DRM_I915_PERF_RECORD_OA_REPORT_LOST:
+             DBG("i915 perf: OA report lost\n");
+             break;
+         }
+      }
+   }
+
+end:
+
+   gen_perf_query_result_accumulate(&query->oa.result, query->queryinfo,
+                                    last, end);
+
+   query->oa.results_accumulated = true;
+   drop_from_unaccumulated_query_list(perf_ctx, query);
+   dec_n_users(perf_ctx);
+
+   return;
+
+error:
+
+   discard_all_queries(perf_ctx);
+}
+
+void
+gen_perf_delete_query(struct gen_perf_context *perf_ctx,
+                      struct gen_perf_query_object *query)
+{
+   struct gen_perf_config *perf_cfg = perf_ctx->perf;
+
+   /* We can assume that the frontend waits for a query to complete
+    * before ever calling into here, so we don't have to worry about
+    * deleting an in-flight query object.
+    */
+   switch (query->queryinfo->kind) {
+   case GEN_PERF_QUERY_TYPE_OA:
+   case GEN_PERF_QUERY_TYPE_RAW:
+      if (query->oa.bo) {
+         if (!query->oa.results_accumulated) {
+            drop_from_unaccumulated_query_list(perf_ctx, query);
+            dec_n_users(perf_ctx);
+         }
+
+         perf_cfg->vtbl.bo_unreference(query->oa.bo);
+         query->oa.bo = NULL;
+      }
+
+      query->oa.results_accumulated = false;
+      break;
+
+   case GEN_PERF_QUERY_TYPE_PIPELINE:
+      if (query->pipeline_stats.bo) {
+         perf_cfg->vtbl.bo_unreference(query->pipeline_stats.bo);
+         query->pipeline_stats.bo = NULL;
+      }
+      break;
+
+   default:
+      unreachable("Unknown query type");
+      break;
+   }
+
+   /* As an indication that the INTEL_performance_query extension is no
+    * longer in use, it's a good time to free our cache of sample
+    * buffers and close any current i915-perf stream.
+    */
+   if (--perf_ctx->n_query_instances == 0) {
+      free_sample_bufs(perf_ctx);
+      gen_perf_close(perf_ctx, query->queryinfo);
+   }
+
+   free(query);
+}
+
+#define GET_FIELD(word, field) (((word)  & field ## _MASK) >> field ## _SHIFT)
+
+static void
+read_gt_frequency(struct gen_perf_context *perf_ctx,
+                  struct gen_perf_query_object *obj)
+{
+   const struct gen_device_info *devinfo = perf_ctx->devinfo;
+   uint32_t start = *((uint32_t *)(obj->oa.map + MI_FREQ_START_OFFSET_BYTES)),
+      end = *((uint32_t *)(obj->oa.map + MI_FREQ_END_OFFSET_BYTES));
+
+   switch (devinfo->gen) {
+   case 7:
+   case 8:
+      obj->oa.gt_frequency[0] = GET_FIELD(start, GEN7_RPSTAT1_CURR_GT_FREQ) * 50ULL;
+      obj->oa.gt_frequency[1] = GET_FIELD(end, GEN7_RPSTAT1_CURR_GT_FREQ) * 50ULL;
+      break;
+   case 9:
+   case 10:
+   case 11:
+      obj->oa.gt_frequency[0] = GET_FIELD(start, GEN9_RPSTAT0_CURR_GT_FREQ) * 50ULL / 3ULL;
+      obj->oa.gt_frequency[1] = GET_FIELD(end, GEN9_RPSTAT0_CURR_GT_FREQ) * 50ULL / 3ULL;
+      break;
+   default:
+      unreachable("unexpected gen");
+   }
+
+   /* Put the numbers into Hz. */
+   obj->oa.gt_frequency[0] *= 1000000ULL;
+   obj->oa.gt_frequency[1] *= 1000000ULL;
+}
+
+static int
+get_oa_counter_data(struct gen_perf_context *perf_ctx,
+                    struct gen_perf_query_object *query,
+                    size_t data_size,
+                    uint8_t *data)
+{
+   struct gen_perf_config *perf_cfg = perf_ctx->perf;
+   const struct gen_perf_query_info *queryinfo = query->queryinfo;
+   int n_counters = queryinfo->n_counters;
+   int written = 0;
+
+   for (int i = 0; i < n_counters; i++) {
+      const struct gen_perf_query_counter *counter = &queryinfo->counters[i];
+      uint64_t *out_uint64;
+      float *out_float;
+      size_t counter_size = gen_perf_query_counter_get_size(counter);
+
+      if (counter_size) {
+         switch (counter->data_type) {
+         case GEN_PERF_COUNTER_DATA_TYPE_UINT64:
+            out_uint64 = (uint64_t *)(data + counter->offset);
+            *out_uint64 =
+               counter->oa_counter_read_uint64(perf_cfg, queryinfo,
+                                               query->oa.result.accumulator);
+            break;
+         case GEN_PERF_COUNTER_DATA_TYPE_FLOAT:
+            out_float = (float *)(data + counter->offset);
+            *out_float =
+               counter->oa_counter_read_float(perf_cfg, queryinfo,
+                                              query->oa.result.accumulator);
+            break;
+         default:
+            /* So far we aren't using uint32, double or bool32... */
+            unreachable("unexpected counter data type");
+         }
+         written = counter->offset + counter_size;
+      }
+   }
+
+   return written;
+}
+
+static int
+get_pipeline_stats_data(struct gen_perf_context *perf_ctx,
+                        struct gen_perf_query_object *query,
+                        size_t data_size,
+                        uint8_t *data)
+
+{
+   struct gen_perf_config *perf_cfg = perf_ctx->perf;
+   const struct gen_perf_query_info *queryinfo = query->queryinfo;
+   int n_counters = queryinfo->n_counters;
+   uint8_t *p = data;
+
+   uint64_t *start = perf_cfg->vtbl.bo_map(perf_ctx->ctx, query->pipeline_stats.bo, MAP_READ);
+   uint64_t *end = start + (STATS_BO_END_OFFSET_BYTES / sizeof(uint64_t));
+
+   for (int i = 0; i < n_counters; i++) {
+      const struct gen_perf_query_counter *counter = &queryinfo->counters[i];
+      uint64_t value = end[i] - start[i];
+
+      if (counter->pipeline_stat.numerator !=
+          counter->pipeline_stat.denominator) {
+         value *= counter->pipeline_stat.numerator;
+         value /= counter->pipeline_stat.denominator;
+      }
+
+      *((uint64_t *)p) = value;
+      p += 8;
+   }
+
+   perf_cfg->vtbl.bo_unmap(query->pipeline_stats.bo);
+
+   return p - data;
+}
+
+void
+gen_perf_get_query_data(struct gen_perf_context *perf_ctx,
+                        struct gen_perf_query_object *query,
+                        int data_size,
+                        unsigned *data,
+                        unsigned *bytes_written)
+{
+   struct gen_perf_config *perf_cfg = perf_ctx->perf;
+   int written = 0;
+
+   switch (query->queryinfo->kind) {
+   case GEN_PERF_QUERY_TYPE_OA:
+   case GEN_PERF_QUERY_TYPE_RAW:
+      if (!query->oa.results_accumulated) {
+         read_gt_frequency(perf_ctx, query);
+         uint32_t *begin_report = query->oa.map;
+         uint32_t *end_report = query->oa.map + MI_RPC_BO_END_OFFSET_BYTES;
+         gen_perf_query_result_read_frequencies(&query->oa.result,
+                                                perf_ctx->devinfo,
+                                                begin_report,
+                                                end_report);
+         accumulate_oa_reports(perf_ctx, query);
+         assert(query->oa.results_accumulated);
+
+         perf_cfg->vtbl.bo_unmap(query->oa.bo);
+         query->oa.map = NULL;
+      }
+      if (query->queryinfo->kind == GEN_PERF_QUERY_TYPE_OA) {
+         written = get_oa_counter_data(perf_ctx, query, data_size, (uint8_t *)data);
+      } else {
+         const struct gen_device_info *devinfo = perf_ctx->devinfo;
+
+         written = gen_perf_query_result_write_mdapi((uint8_t *)data, data_size,
+                                                     devinfo, &query->oa.result,
+                                                     query->oa.gt_frequency[0],
+                                                     query->oa.gt_frequency[1]);
+      }
+      break;
+
+   case GEN_PERF_QUERY_TYPE_PIPELINE:
+      written = get_pipeline_stats_data(perf_ctx, query, data_size, (uint8_t *)data);
+      break;
+
+   default:
+      unreachable("Unknown query type");
+      break;
+   }
+
+   if (bytes_written)
+      *bytes_written = written;
+}
+
+void
+gen_perf_dump_query_count(struct gen_perf_context *perf_ctx)
+{
+   DBG("Queries: (Open queries = %d, OA users = %d)\n",
+       perf_ctx->n_active_oa_queries, perf_ctx->n_oa_users);
+}
+
+void
+gen_perf_dump_query(struct gen_perf_context *ctx,
+                    struct gen_perf_query_object *obj,
+                    void *current_batch)
+{
+   switch (obj->queryinfo->kind) {
+   case GEN_PERF_QUERY_TYPE_OA:
+   case GEN_PERF_QUERY_TYPE_RAW:
+      DBG("BO: %-4s OA data: %-10s %-15s\n",
+          obj->oa.bo ? "yes," : "no,",
+          gen_perf_is_query_ready(ctx, obj, current_batch) ? "ready," : "not ready,",
+          obj->oa.results_accumulated ? "accumulated" : "not accumulated");
+      break;
+   case GEN_PERF_QUERY_TYPE_PIPELINE:
+      DBG("BO: %-4s\n",
+          obj->pipeline_stats.bo ? "yes" : "no");
+      break;
+   default:
+      unreachable("Unknown query type");
+      break;
+   }
+}
diff --git a/src/intel/perf/gen_perf_query.h b/src/intel/perf/gen_perf_query.h
new file mode 100644
index 00000000000..a0246501f76
--- /dev/null
+++ b/src/intel/perf/gen_perf_query.h
@@ -0,0 +1,88 @@
+/*
+ * Copyright © 2019 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#ifndef GEN_PERF_QUERY_H
+#define GEN_PERF_QUERY_H
+
+#include <stdint.h>
+
+struct gen_device_info;
+
+struct gen_perf_config;
+struct gen_perf_context;
+struct gen_perf_query_object;
+
+struct gen_perf_context *gen_perf_new_context(void *parent);
+
+void gen_perf_init_context(struct gen_perf_context *perf_ctx,
+                           struct gen_perf_config *perf_cfg,
+                           void * ctx,  /* driver context (eg, brw_context) */
+                           void * bufmgr,  /* eg brw_bufmgr */
+                           const struct gen_device_info *devinfo,
+                           uint32_t hw_ctx,
+                           int drm_fd);
+
+const struct gen_perf_query_info* gen_perf_query_info(const struct gen_perf_query_object *);
+
+
+void gen_perf_init_context(struct gen_perf_context *perf_ctx,
+                           struct gen_perf_config *perf_cfg,
+                           void * ctx,  /* driver context (eg, brw_context) */
+                           void * bufmgr,  /* eg brw_bufmgr */
+                           const struct gen_device_info *devinfo,
+                           uint32_t hw_ctx,
+                           int drm_fd);
+
+struct gen_perf_config *gen_perf_config(struct gen_perf_context *ctx);
+
+int gen_perf_active_queries(struct gen_perf_context *perf_ctx,
+                            const struct gen_perf_query_info *query);
+
+struct gen_perf_query_object *
+gen_perf_new_query(struct gen_perf_context *, unsigned query_index);
+
+
+bool gen_perf_begin_query(struct gen_perf_context *perf_ctx,
+                          struct gen_perf_query_object *query);
+void gen_perf_end_query(struct gen_perf_context *perf_ctx,
+                        struct gen_perf_query_object *query);
+void gen_perf_wait_query(struct gen_perf_context *perf_ctx,
+                         struct gen_perf_query_object *query,
+                         void *current_batch);
+bool gen_perf_is_query_ready(struct gen_perf_context *perf_ctx,
+                             struct gen_perf_query_object *query,
+                             void *current_batch);
+void gen_perf_delete_query(struct gen_perf_context *perf_ctx,
+                           struct gen_perf_query_object *query);
+void gen_perf_get_query_data(struct gen_perf_context *perf_ctx,
+                             struct gen_perf_query_object *query,
+                             int data_size,
+                             unsigned *data,
+                             unsigned *bytes_written);
+
+void gen_perf_dump_query_count(struct gen_perf_context *perf_ctx);
+void gen_perf_dump_query(struct gen_perf_context *perf_ctx,
+                         struct gen_perf_query_object *obj,
+                         void *current_batch);
+
+#endif /* GEN_PERF_QUERY_H */
diff --git a/src/intel/perf/meson.build b/src/intel/perf/meson.build
index 5fae9058f83..757eec2553e 100644
--- a/src/intel/perf/meson.build
+++ b/src/intel/perf/meson.build
@@ -17,6 +17,7 @@ endforeach
 
 gen_perf_sources = [
   'gen_perf.c',
+  'gen_perf_query.c',
   'gen_perf_mdapi.c',
 ]
 
diff --git a/src/mesa/drivers/dri/i965/brw_context.h b/src/mesa/drivers/dri/i965/brw_context.h
index 05933af4430..36dc53cc9d5 100644
--- a/src/mesa/drivers/dri/i965/brw_context.h
+++ b/src/mesa/drivers/dri/i965/brw_context.h
@@ -51,6 +51,7 @@
 #include "intel_screen.h"
 #include "intel_tex_obj.h"
 #include "perf/gen_perf.h"
+#include "perf/gen_perf_query.h"
 
 #ifdef __cplusplus
 extern "C" {
diff --git a/src/mesa/drivers/dri/i965/brw_performance_query.c b/src/mesa/drivers/dri/i965/brw_performance_query.c
index 7e0c66f895c..11505fab9f3 100644
--- a/src/mesa/drivers/dri/i965/brw_performance_query.c
+++ b/src/mesa/drivers/dri/i965/brw_performance_query.c
@@ -75,6 +75,7 @@
 #include "perf/gen_perf.h"
 #include "perf/gen_perf_regs.h"
 #include "perf/gen_perf_mdapi.h"
+#include "perf/gen_perf_query.h"
 
 #define FILE_DEBUG_FLAG DEBUG_PERFMON