Ony non-llc architectures where we are primarily reading back the results of the GPU queries, then we can improve performance by using a cacheable mapping of the results. Unfortunately, enabling snooping makes the writes from the GPU slower, which may adversely affect pipelined query operations (where the results are used directly by the GPU and not CPU).
Signed-off-by: Chris Wilson <[email protected]> Cc: Kenneth Graunke <[email protected]> Cc: Matt Turner <[email protected]> --- src/mesa/drivers/dri/i965/brw_bufmgr.c | 24 +++++++++++++++++++++++ src/mesa/drivers/dri/i965/brw_bufmgr.h | 2 ++ src/mesa/drivers/dri/i965/gen6_queryobj.c | 2 ++ 3 files changed, 28 insertions(+) diff --git a/src/mesa/drivers/dri/i965/brw_bufmgr.c b/src/mesa/drivers/dri/i965/brw_bufmgr.c index d9e8453787c..3c3bdee3d2a 100644 --- a/src/mesa/drivers/dri/i965/brw_bufmgr.c +++ b/src/mesa/drivers/dri/i965/brw_bufmgr.c @@ -946,6 +946,30 @@ brw_bo_unreference(struct brw_bo *bo) } } +static bool +__brw_bo_set_caching(struct brw_bo *bo, int caching) +{ + struct drm_i915_gem_caching arg = { + .handle = bo->gem_handle, + .caching = caching + }; + return drmIoctl(bo->bufmgr->fd, DRM_IOCTL_I915_GEM_SET_CACHING, &arg) == 0; +} + +void +brw_bo_set_cache_coherent(struct brw_bo *bo) +{ + assert(!bo->external); + if (bo->cache_coherent) + return; + + if (!__brw_bo_set_caching(bo, I915_CACHING_CACHED)) + return; + + bo->reusable = false; + bo->cache_coherent = true; +} + static void bo_wait_with_stall_warning(struct brw_context *brw, struct brw_bo *bo, diff --git a/src/mesa/drivers/dri/i965/brw_bufmgr.h b/src/mesa/drivers/dri/i965/brw_bufmgr.h index e1f46b091ce..6f0fe54f79f 100644 --- a/src/mesa/drivers/dri/i965/brw_bufmgr.h +++ b/src/mesa/drivers/dri/i965/brw_bufmgr.h @@ -273,6 +273,8 @@ void brw_bo_unreference(struct brw_bo *bo); #define MAP_INTERNAL_MASK (0xff << 24) #define MAP_RAW (0x01 << 24) +void brw_bo_set_cache_coherent(struct brw_bo *bo); + /** * Maps the buffer into userspace. * diff --git a/src/mesa/drivers/dri/i965/gen6_queryobj.c b/src/mesa/drivers/dri/i965/gen6_queryobj.c index 17c10b135d1..dc70e2a568a 100644 --- a/src/mesa/drivers/dri/i965/gen6_queryobj.c +++ b/src/mesa/drivers/dri/i965/gen6_queryobj.c @@ -325,6 +325,8 @@ gen6_alloc_query(struct brw_context *brw, struct brw_query_object *query) query->bo = brw_bo_alloc(brw->bufmgr, "query results", 4096, BRW_MEMZONE_OTHER); + brw_bo_set_cache_coherent(query->bo); + query->results = brw_bo_map(brw, query->bo, MAP_COHERENT | MAP_PERSISTENT | MAP_READ | MAP_ASYNC); -- 2.19.0 _______________________________________________ mesa-dev mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/mesa-dev
