From 3eb6258db7b7590493e473bf654409212061b8b0 Mon Sep 17 00:00:00 2001 From: Kenneth Graunke Date: Thu, 11 Dec 2014 02:26:39 -0800 Subject: [PATCH] i965/query: Cache whether the batch references the query BO. Chris Wilson noted that repeated calls to CheckQuery() would call drm_intel_bo_references(brw->batch.bo, query->bo) on each invocation, which is expensive. Once we've flushed, we know that future batches won't reference query->bo, so there's no point in asking more than once. This patch adds a brw_query_object::flushed flag, which is a conservative estimate of whether the batch has been flushed. On the first call to CheckQuery() or WaitQuery(), we check if the batch references query->bo. If not, it must have been flushed for some reason (such as being full). We record that it was flushed. If it does reference query->bo, we explicitly flush, and record that we did so. Any subsequent checks will simply see that query->flushed is set, and skip the drm_intel_bo_references() call. Inspired by a patch from Chris Wilson. According to Eero, this does not affect the performance of Witcher 2 on Haswell, but approximately halves the userspace CPU usage. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=86969 Signed-off-by: Kenneth Graunke Reviewed-by: Ben Widawsky Reviewed-by: Ian Romanick --- src/mesa/drivers/dri/i965/brw_context.h | 3 +++ src/mesa/drivers/dri/i965/gen6_queryobj.c | 27 +++++++++++++++++++---- 2 files changed, 26 insertions(+), 4 deletions(-) diff --git a/src/mesa/drivers/dri/i965/brw_context.h b/src/mesa/drivers/dri/i965/brw_context.h index 1b8f0bbfcac..a63c4834c26 100644 --- a/src/mesa/drivers/dri/i965/brw_context.h +++ b/src/mesa/drivers/dri/i965/brw_context.h @@ -831,6 +831,9 @@ struct brw_query_object { /** Last index in bo with query data for this object. */ int last_index; + + /** True if we know the batch has been flushed since we ended the query. */ + bool flushed; }; struct intel_sync_object { diff --git a/src/mesa/drivers/dri/i965/gen6_queryobj.c b/src/mesa/drivers/dri/i965/gen6_queryobj.c index 0d513908cdf..de71bb565f5 100644 --- a/src/mesa/drivers/dri/i965/gen6_queryobj.c +++ b/src/mesa/drivers/dri/i965/gen6_queryobj.c @@ -281,6 +281,27 @@ gen6_end_query(struct gl_context *ctx, struct gl_query_object *q) default: unreachable("Unrecognized query target in brw_end_query()"); } + + /* The current batch contains the commands to handle EndQuery(), + * but they won't actually execute until it is flushed. + */ + query->flushed = false; +} + +/** + * Flush the batch if it still references the query object BO. + */ +static void +flush_batch_if_needed(struct brw_context *brw, struct brw_query_object *query) +{ + /* If the batch doesn't reference the BO, it must have been flushed + * (for example, due to being full). Record that it's been flushed. + */ + query->flushed = query->flushed || + !drm_intel_bo_references(brw->batch.bo, query->bo); + + if (!query->flushed) + intel_batchbuffer_flush(brw); } /** @@ -298,8 +319,7 @@ static void gen6_wait_query(struct gl_context *ctx, struct gl_query_object *q) * still contributing to it, flush it now to finish that work so the * result will become available (eventually). */ - if (drm_intel_bo_references(brw->batch.bo, query->bo)) - intel_batchbuffer_flush(brw); + flush_batch_if_needed(brw, query); gen6_queryobj_get_results(ctx, query); } @@ -328,8 +348,7 @@ static void gen6_check_query(struct gl_context *ctx, struct gl_query_object *q) * not ready yet on the first time it is queried. This ensures that * the async query will return true in finite time. */ - if (drm_intel_bo_references(brw->batch.bo, query->bo)) - intel_batchbuffer_flush(brw); + flush_batch_if_needed(brw, query); if (!drm_intel_bo_busy(query->bo)) { gen6_queryobj_get_results(ctx, query); -- 2.30.2