Improves citybench performance by 39.8638% +/- 2.26632% (n=10) (at
default resolution and about the same for 320x240).
---
src/mesa/drivers/dri/intel/intel_batchbuffer.c | 5 -----
src/mesa/drivers/dri/intel/intel_context.c | 21 +++++++++++++++++----
2 files changed, 17 insertions(+), 9 deletions(-)
diff --git a/src/mesa/drivers/dri/intel/intel_batchbuffer.c
b/src/mesa/drivers/dri/intel/intel_batchbuffer.c
index d10e008..5631c19 100644
--- a/src/mesa/drivers/dri/intel/intel_batchbuffer.c
+++ b/src/mesa/drivers/dri/intel/intel_batchbuffer.c
@@ -211,11 +211,6 @@ _intel_batchbuffer_flush(struct intel_context *intel,
if (intel->batch.used == 0)
return 0;
- if (intel->first_post_swapbuffers_batch == NULL) {
- intel->first_post_swapbuffers_batch = intel->batch.bo;
- drm_intel_bo_reference(intel->first_post_swapbuffers_batch);
- }
-
if (unlikely(INTEL_DEBUG & DEBUG_BATCH))
fprintf(stderr, "%s:%d: Batchbuffer flush with %db used\n", file, line,
4*intel->batch.used);
diff --git a/src/mesa/drivers/dri/intel/intel_context.c
b/src/mesa/drivers/dri/intel/intel_context.c
index 377bcbc..3d3feb6 100644
--- a/src/mesa/drivers/dri/intel/intel_context.c
+++ b/src/mesa/drivers/dri/intel/intel_context.c
@@ -419,18 +419,31 @@ intel_prepare_render(struct intel_context *intel)
* We're using intelDRI2Flush (called from the loader before
* swapbuffer) and glFlush (for front buffer rendering) as the
* indicator that a frame is done and then throttle when we get
- * here as we prepare to render the next frame. At this point for
+ * here as we prepare to render the next frame. At this point our
* round trips for swap/copy and getting new buffers are done and
- * we'll spend less time waiting on the GPU.
+ * we'll spend less time waiting on the GPU when we throttle here.
*
* Unfortunately, we don't have a handle to the batch containing
* the swap, and getting our hands on that doesn't seem worth it,
- * so we just us the first batch we emitted after the last swap.
+ * so we just use the first batch we emitted after the last swap.
+ * To bring the point we wait on closer to the swapbuffers, we make
+ * a tiny batchbuffer containing just a noop and flush it out. The
+ * overhead of it is worth the savings on apps that only emit one or
+ * a few batchbuffers per frame.
*/
if (intel->need_throttle && intel->first_post_swapbuffers_batch) {
drm_intel_bo_wait_rendering(intel->first_post_swapbuffers_batch);
drm_intel_bo_unreference(intel->first_post_swapbuffers_batch);
- intel->first_post_swapbuffers_batch = NULL;
+
+ BEGIN_BATCH(1);
+ OUT_BATCH(MI_NOOP);
+ ADVANCE_BATCH();
+
+ intel->first_post_swapbuffers_batch = intel->batch.bo;
+ drm_intel_bo_reference(intel->batch.bo);
+
+ intel_batchbuffer_flush(intel);
+
intel->need_throttle = false;
}
}
--
1.7.9
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