diff options
author | Mark Janes <[email protected]> | 2019-06-28 14:46:12 -0700 |
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committer | Mark Janes <[email protected]> | 2019-08-07 21:33:55 -0700 |
commit | 018f9b81e57f735d699706c94b532a46d5667e28 (patch) | |
tree | 2dec4ef1a0730422713c7a936c805f5dd0abfd60 /src/intel/perf/gen_perf.c | |
parent | 52d3db9ab68ccc6d6ea25e3ef30d2ce3f92c0050 (diff) |
intel/perf: refactor gen_perf_begin_query into gen_perf
Reviewed-by: Kenneth Graunke <[email protected]>
Diffstat (limited to 'src/intel/perf/gen_perf.c')
-rw-r--r-- | src/intel/perf/gen_perf.c | 256 |
1 files changed, 256 insertions, 0 deletions
diff --git a/src/intel/perf/gen_perf.c b/src/intel/perf/gen_perf.c index 48e3d59f3d4..26f6da88d90 100644 --- a/src/intel/perf/gen_perf.c +++ b/src/intel/perf/gen_perf.c @@ -39,8 +39,11 @@ #include "dev/gen_debug.h" #include "dev/gen_device_info.h" #include "util/bitscan.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 MAP_READ (1 << 0) #define MAP_WRITE (1 << 1) @@ -1027,3 +1030,256 @@ gen_perf_init_context(struct gen_perf_context *perf_ctx, 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. + * + * Theoretically there could be opportunities to minimize how much of the + * GPU pipeline is drained, or that we stall for, when we know what specific + * units the performance counters being queried relate to but we don't + * currently attempt to be clever here. + * + * Note: with our current simple approach here then for back-to-back queries + * we will redundantly emit duplicate commands to synchronize the command + * streamer with the rest of the GPU pipeline, but we assume that in HW the + * second synchronization is effectively a NOOP. + * + * 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_mi_flush(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 = gen_perf_query_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 (!gen_perf_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; + + /* We flush the batchbuffer here to minimize the chances that MI_RPC + * delimiting commands end up in different batchbuffers. If that's the + * case, the measurement will include the time it takes for the kernel + * scheduler to load a new request into the hardware. This is manifested in + * tools like frameretrace by spikes in the "GPU Core Clocks" counter. + */ + perf_cfg->vtbl.batchbuffer_flush(perf_ctx->ctx, __FILE__, __LINE__); + + /* 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); + perf_cfg->vtbl.capture_frequency_stat_register(perf_ctx->ctx, query->oa.bo, + 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. */ + gen_perf_snapshot_statistics_registers(perf_ctx->ctx , perf_cfg, query, 0); + + ++perf_ctx->n_active_pipeline_stats_queries; + break; + + default: + unreachable("Unknown query type"); + break; + } + + return true; +} |