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authorMarek Olšák <[email protected]>2018-09-07 15:37:45 -0400
committerMarek Olšák <[email protected]>2018-09-14 21:05:37 -0400
commit7d41a7593a540d118926691a77ad4c59e9559143 (patch)
tree8df2c8037b2d40e59bb0ed341d93129615943bd2 /src/gallium/auxiliary
parent936e0dcd619bc092b9869b4be2e1b20c3631131f (diff)
gallium/util: start with a random L3 cache index for AMD Zen
Diffstat (limited to 'src/gallium/auxiliary')
-rw-r--r--src/gallium/auxiliary/util/u_helpers.c20
1 files changed, 16 insertions, 4 deletions
diff --git a/src/gallium/auxiliary/util/u_helpers.c b/src/gallium/auxiliary/util/u_helpers.c
index 8095242efd9..14367e5a118 100644
--- a/src/gallium/auxiliary/util/u_helpers.c
+++ b/src/gallium/auxiliary/util/u_helpers.c
@@ -30,6 +30,7 @@
#include "util/u_inlines.h"
#include "util/u_upload_mgr.h"
#include "util/u_thread.h"
+#include "util/os_time.h"
#include <inttypes.h>
/**
@@ -120,6 +121,17 @@ util_upload_index_buffer(struct pipe_context *pipe,
return *out_buffer != NULL;
}
+static unsigned L3_cache_number;
+static once_flag init_cache_number_flag = ONCE_FLAG_INIT;
+
+static void
+util_init_cache_number(void)
+{
+ /* Get a semi-random number. */
+ int64_t t = os_time_get_nano();
+ L3_cache_number = (t ^ (t >> 8) ^ (t >> 16));
+}
+
/**
* Called by MakeCurrent. Used to notify the driver that the application
* thread may have been changed.
@@ -141,12 +153,12 @@ util_context_thread_changed(struct pipe_context *ctx, thrd_t *upper_thread)
/* If the main thread is not pinned, choose the L3 cache. */
if (cache == -1) {
- unsigned num_caches = util_cpu_caps.nr_cpus /
- util_cpu_caps.cores_per_L3;
- static unsigned last_cache;
+ unsigned num_L3_caches = util_cpu_caps.nr_cpus /
+ util_cpu_caps.cores_per_L3;
/* Choose a different L3 cache for each subsequent MakeCurrent. */
- cache = p_atomic_inc_return(&last_cache) % num_caches;
+ call_once(&init_cache_number_flag, util_init_cache_number);
+ cache = p_atomic_inc_return(&L3_cache_number) % num_L3_caches;
util_pin_thread_to_L3(current, cache, util_cpu_caps.cores_per_L3);
}