[Mesa-dev] [PATCH 7/7] gallium/radeon: always flush asynchronously and wait after begin_new_cs

[Marek Olšák]

From: Marek Olšák <marek.olsak at amd.com>

This hides the overhead of everything in the driver after the CS flush and
before returning from pipe_context::flush.
Only microbenchmarks will benefit.

+2% FPS for glxgears.
---
 src/gallium/drivers/radeon/r600_pipe_common.c | 12 ++++++++----
 src/gallium/drivers/radeonsi/si_hw_context.c  |  3 +++
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/src/gallium/drivers/radeon/r600_pipe_common.c b/src/gallium/drivers/radeon/r600_pipe_common.c
index 47d4058..ce84139 100644
--- a/src/gallium/drivers/radeon/r600_pipe_common.c
+++ b/src/gallium/drivers/radeon/r600_pipe_common.c
@@ -359,38 +359,36 @@ void r600_postflush_resume_features(struct r600_common_context *ctx)
 		r600_resume_queries(ctx);
 }
 
 static void r600_flush_from_st(struct pipe_context *ctx,
 			       struct pipe_fence_handle **fence,
 			       unsigned flags)
 {
 	struct pipe_screen *screen = ctx->screen;
 	struct r600_common_context *rctx = (struct r600_common_context *)ctx;
 	struct radeon_winsys *ws = rctx->ws;
-	unsigned rflags = 0;
 	struct pipe_fence_handle *gfx_fence = NULL;
 	struct pipe_fence_handle *sdma_fence = NULL;
 	bool deferred_fence = false;
+	unsigned rflags = RADEON_FLUSH_ASYNC;
 
 	if (flags & PIPE_FLUSH_END_OF_FRAME)
 		rflags |= RADEON_FLUSH_END_OF_FRAME;
-	if (flags & PIPE_FLUSH_DEFERRED)
-		rflags |= RADEON_FLUSH_ASYNC;
 
 	/* DMA IBs are preambles to gfx IBs, therefore must be flushed first. */
 	if (rctx->dma.cs)
 		rctx->dma.flush(rctx, rflags, fence ? &sdma_fence : NULL);
 
 	if (!radeon_emitted(rctx->gfx.cs, rctx->initial_gfx_cs_size)) {
 		if (fence)
 			ws->fence_reference(&gfx_fence, rctx->last_gfx_fence);
-		if (!(rflags & RADEON_FLUSH_ASYNC))
+		if (!(flags & PIPE_FLUSH_DEFERRED))
 			ws->cs_sync_flush(rctx->gfx.cs);
 	} else {
 		/* Instead of flushing, create a deferred fence. Constraints:
 		 * - The state tracker must allow a deferred flush.
 		 * - The state tracker must request a fence.
 		 * Thread safety in fence_finish must be ensured by the state tracker.
 		 */
 		if (flags & PIPE_FLUSH_DEFERRED && fence) {
 			gfx_fence = rctx->ws->cs_get_next_fence(rctx->gfx.cs);
 			deferred_fence = true;
@@ -412,20 +410,26 @@ static void r600_flush_from_st(struct pipe_context *ctx,
 		multi_fence->sdma = sdma_fence;
 
 		if (deferred_fence) {
 			multi_fence->gfx_unflushed.ctx = rctx;
 			multi_fence->gfx_unflushed.ib_index = rctx->num_gfx_cs_flushes;
 		}
 
 		screen->fence_reference(screen, fence, NULL);
 		*fence = (struct pipe_fence_handle*)multi_fence;
 	}
+
+	if (!(flags & PIPE_FLUSH_DEFERRED)) {
+		if (rctx->dma.cs)
+			ws->cs_sync_flush(rctx->dma.cs);
+		ws->cs_sync_flush(rctx->gfx.cs);
+	}
 }
 
 static void r600_flush_dma_ring(void *ctx, unsigned flags,
 				struct pipe_fence_handle **fence)
 {
 	struct r600_common_context *rctx = (struct r600_common_context *)ctx;
 	struct radeon_winsys_cs *cs = rctx->dma.cs;
 	struct radeon_saved_cs saved;
 	bool check_vm =
 		(rctx->screen->debug_flags & DBG_CHECK_VM) &&
diff --git a/src/gallium/drivers/radeonsi/si_hw_context.c b/src/gallium/drivers/radeonsi/si_hw_context.c
index e51abfc..e15f6a9 100644
--- a/src/gallium/drivers/radeonsi/si_hw_context.c
+++ b/src/gallium/drivers/radeonsi/si_hw_context.c
@@ -101,20 +101,23 @@ void si_context_gfx_flush(void *context, unsigned flags,
 
 	if (ctx->gfx_flush_in_progress)
 		return;
 
 	if (!radeon_emitted(cs, ctx->b.initial_gfx_cs_size))
 		return;
 
 	if (r600_check_device_reset(&ctx->b))
 		return;
 
+	if (ctx->screen->b.debug_flags & DBG_CHECK_VM)
+		flags &= ~RADEON_FLUSH_ASYNC;
+
 	/* If the state tracker is flushing the GFX IB, r600_flush_from_st is
 	 * responsible for flushing the DMA IB and merging the fences from both.
 	 * This code is only needed when the driver flushes the GFX IB
 	 * internally, and it never asks for a fence handle.
 	 */
 	if (radeon_emitted(ctx->b.dma.cs, 0)) {
 		assert(fence == NULL); /* internal flushes only */
 		ctx->b.dma.flush(ctx, flags, NULL);
 	}
 
-- 
2.7.4