[Mesa-dev] [PATCH] radeonsi: use CP DMA for the null const buffer clear on CIK

Samuel Pitoiset samuel.pitoiset at gmail.com
Fri Apr 12 16:23:38 UTC 2019


I would suggest to document that workaround somewhere in the code.

On 4/12/19 5:17 PM, Marek Olšák wrote:
> From: Marek Olšák <marek.olsak at amd.com>
>
> This is a workaround for a thread deadlock that I have no idea
> why it occurs.
>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=108879
> Fixes: 9b331e462e5021d994859756d46cd2519d9c9c6e
> ---
>   src/gallium/drivers/radeonsi/si_clear.c        | 6 +++---
>   src/gallium/drivers/radeonsi/si_compute_blit.c | 8 +++++---
>   src/gallium/drivers/radeonsi/si_pipe.c         | 2 +-
>   src/gallium/drivers/radeonsi/si_pipe.h         | 3 ++-
>   src/gallium/drivers/radeonsi/si_test_dma.c     | 2 +-
>   5 files changed, 12 insertions(+), 9 deletions(-)
>
> diff --git a/src/gallium/drivers/radeonsi/si_clear.c b/src/gallium/drivers/radeonsi/si_clear.c
> index e1805f2a1c9..ead680b857b 100644
> --- a/src/gallium/drivers/radeonsi/si_clear.c
> +++ b/src/gallium/drivers/radeonsi/si_clear.c
> @@ -256,21 +256,21 @@ void vi_dcc_clear_level(struct si_context *sctx,
>   		 * would be more efficient than separate per-layer clear operations.
>   		 */
>   		assert(tex->buffer.b.b.nr_storage_samples <= 2 || num_layers == 1);
>   
>   		dcc_offset += tex->surface.u.legacy.level[level].dcc_offset;
>   		clear_size = tex->surface.u.legacy.level[level].dcc_fast_clear_size *
>   			     num_layers;
>   	}
>   
>   	si_clear_buffer(sctx, dcc_buffer, dcc_offset, clear_size,
> -			&clear_value, 4, SI_COHERENCY_CB_META);
> +			&clear_value, 4, SI_COHERENCY_CB_META, false);
>   }
>   
>   /* Set the same micro tile mode as the destination of the last MSAA resolve.
>    * This allows hitting the MSAA resolve fast path, which requires that both
>    * src and dst micro tile modes match.
>    */
>   static void si_set_optimal_micro_tile_mode(struct si_screen *sscreen,
>   					   struct si_texture *tex)
>   {
>   	if (tex->buffer.b.is_shared ||
> @@ -489,21 +489,21 @@ static void si_do_fast_color_clear(struct si_context *sctx,
>   
>   			/* DCC fast clear with MSAA should clear CMASK to 0xC. */
>   			if (tex->buffer.b.b.nr_samples >= 2 && tex->cmask_buffer) {
>   				/* TODO: This doesn't work with MSAA. */
>   				if (eliminate_needed)
>   					continue;
>   
>   				uint32_t clear_value = 0xCCCCCCCC;
>   				si_clear_buffer(sctx, &tex->cmask_buffer->b.b,
>   						tex->cmask_offset, tex->surface.cmask_size,
> -						&clear_value, 4, SI_COHERENCY_CB_META);
> +						&clear_value, 4, SI_COHERENCY_CB_META, false);
>   				fmask_decompress_needed = true;
>   			}
>   
>   			vi_dcc_clear_level(sctx, tex, 0, reset_value);
>   			tex->separate_dcc_dirty = true;
>   		} else {
>   			if (too_small)
>   				continue;
>   
>   			/* 128-bit formats are unusupported */
> @@ -517,21 +517,21 @@ static void si_do_fast_color_clear(struct si_context *sctx,
>   
>   			/* ensure CMASK is enabled */
>   			si_alloc_separate_cmask(sctx->screen, tex);
>   			if (!tex->cmask_buffer)
>   				continue;
>   
>   			/* Do the fast clear. */
>   			uint32_t clear_value = 0;
>   			si_clear_buffer(sctx, &tex->cmask_buffer->b.b,
>   					tex->cmask_offset, tex->surface.cmask_size,
> -					&clear_value, 4, SI_COHERENCY_CB_META);
> +					&clear_value, 4, SI_COHERENCY_CB_META, false);
>   			eliminate_needed = true;
>   		}
>   
>   		if ((eliminate_needed || fmask_decompress_needed) &&
>   		    !(tex->dirty_level_mask & (1 << level))) {
>   			tex->dirty_level_mask |= 1 << level;
>   			p_atomic_inc(&sctx->screen->compressed_colortex_counter);
>   		}
>   
>   		/* We can change the micro tile mode before a full clear. */
> diff --git a/src/gallium/drivers/radeonsi/si_compute_blit.c b/src/gallium/drivers/radeonsi/si_compute_blit.c
> index 1abeac6adb0..fb0d8d2f1b6 100644
> --- a/src/gallium/drivers/radeonsi/si_compute_blit.c
> +++ b/src/gallium/drivers/radeonsi/si_compute_blit.c
> @@ -179,21 +179,22 @@ static void si_compute_do_clear_or_copy(struct si_context *sctx,
>   
>   	/* Restore states. */
>   	ctx->bind_compute_state(ctx, saved_cs);
>   	ctx->set_shader_buffers(ctx, PIPE_SHADER_COMPUTE, 0, src ? 2 : 1, saved_sb,
>   				saved_writable_mask);
>   	si_compute_internal_end(sctx);
>   }
>   
>   void si_clear_buffer(struct si_context *sctx, struct pipe_resource *dst,
>   		     uint64_t offset, uint64_t size, uint32_t *clear_value,
> -		     uint32_t clear_value_size, enum si_coherency coher)
> +		     uint32_t clear_value_size, enum si_coherency coher,
> +		     bool force_cpdma)
>   {
>   	if (!size)
>   		return;
>   
>   	unsigned clear_alignment = MIN2(clear_value_size, 4);
>   
>   	assert(clear_value_size != 3 && clear_value_size != 6); /* 12 is allowed. */
>   	assert(offset % clear_alignment == 0);
>   	assert(size % clear_alignment == 0);
>   	assert(size < (UINT_MAX & ~0xf)); /* TODO: test 64-bit sizes in all codepaths */
> @@ -243,21 +244,22 @@ void si_clear_buffer(struct si_context *sctx, struct pipe_resource *dst,
>   		return;
>   	}
>   
>   	uint64_t aligned_size = size & ~3ull;
>   	if (aligned_size >= 4) {
>   		/* Before GFX9, CP DMA was very slow when clearing GTT, so never
>   		 * use CP DMA clears on those chips, because we can't be certain
>   		 * about buffer placements.
>   		 */
>   		if (clear_value_size > 4 ||
> -		    (clear_value_size == 4 &&
> +		    (!force_cpdma &&
> +		     clear_value_size == 4 &&
>   		     offset % 4 == 0 &&
>   		     (size > 32*1024 || sctx->chip_class <= VI))) {
>   			si_compute_do_clear_or_copy(sctx, dst, offset, NULL, 0,
>   						    aligned_size, clear_value,
>   						    clear_value_size, coher);
>   		} else {
>   			assert(clear_value_size == 4);
>   			si_cp_dma_clear_buffer(sctx, sctx->gfx_cs, dst, offset,
>   					       aligned_size, *clear_value, 0, coher,
>   					       get_cache_policy(sctx, coher, size));
> @@ -277,21 +279,21 @@ void si_clear_buffer(struct si_context *sctx, struct pipe_resource *dst,
>   	}
>   }
>   
>   static void si_pipe_clear_buffer(struct pipe_context *ctx,
>   				 struct pipe_resource *dst,
>   				 unsigned offset, unsigned size,
>   				 const void *clear_value,
>   				 int clear_value_size)
>   {
>   	si_clear_buffer((struct si_context*)ctx, dst, offset, size, (uint32_t*)clear_value,
> -			clear_value_size, SI_COHERENCY_SHADER);
> +			clear_value_size, SI_COHERENCY_SHADER, false);
>   }
>   
>   void si_copy_buffer(struct si_context *sctx,
>   		    struct pipe_resource *dst, struct pipe_resource *src,
>   		    uint64_t dst_offset, uint64_t src_offset, unsigned size)
>   {
>   	if (!size)
>   		return;
>   
>   	enum si_coherency coher = SI_COHERENCY_SHADER;
> diff --git a/src/gallium/drivers/radeonsi/si_pipe.c b/src/gallium/drivers/radeonsi/si_pipe.c
> index 5caeb575623..5d376e6181a 100644
> --- a/src/gallium/drivers/radeonsi/si_pipe.c
> +++ b/src/gallium/drivers/radeonsi/si_pipe.c
> @@ -634,21 +634,21 @@ static struct pipe_context *si_create_context(struct pipe_screen *screen,
>   			  sizeof(sctx->sample_positions), &sctx->sample_positions);
>   
>   	/* this must be last */
>   	si_begin_new_gfx_cs(sctx);
>   
>   	if (sctx->chip_class == CIK) {
>   		/* Clear the NULL constant buffer, because loads should return zeros. */
>   		uint32_t clear_value = 0;
>   		si_clear_buffer(sctx, sctx->null_const_buf.buffer, 0,
>   				sctx->null_const_buf.buffer->width0,
> -				&clear_value, 4, SI_COHERENCY_SHADER);
> +				&clear_value, 4, SI_COHERENCY_SHADER, true);
>   	}
>   	return &sctx->b;
>   fail:
>   	fprintf(stderr, "radeonsi: Failed to create a context.\n");
>   	si_destroy_context(&sctx->b);
>   	return NULL;
>   }
>   
>   static struct pipe_context *si_pipe_create_context(struct pipe_screen *screen,
>   						   void *priv, unsigned flags)
> diff --git a/src/gallium/drivers/radeonsi/si_pipe.h b/src/gallium/drivers/radeonsi/si_pipe.h
> index 301d38649bf..aaa95f32d20 100644
> --- a/src/gallium/drivers/radeonsi/si_pipe.h
> +++ b/src/gallium/drivers/radeonsi/si_pipe.h
> @@ -1182,21 +1182,22 @@ bool vi_alpha_is_on_msb(enum pipe_format format);
>   void vi_dcc_clear_level(struct si_context *sctx,
>   			struct si_texture *tex,
>   			unsigned level, unsigned clear_value);
>   void si_init_clear_functions(struct si_context *sctx);
>   
>   /* si_compute_blit.c */
>   unsigned si_get_flush_flags(struct si_context *sctx, enum si_coherency coher,
>   			    enum si_cache_policy cache_policy);
>   void si_clear_buffer(struct si_context *sctx, struct pipe_resource *dst,
>   		     uint64_t offset, uint64_t size, uint32_t *clear_value,
> -		     uint32_t clear_value_size, enum si_coherency coher);
> +		     uint32_t clear_value_size, enum si_coherency coher,
> +		     bool force_cpdma);
>   void si_copy_buffer(struct si_context *sctx,
>   		    struct pipe_resource *dst, struct pipe_resource *src,
>   		    uint64_t dst_offset, uint64_t src_offset, unsigned size);
>   void si_compute_copy_image(struct si_context *sctx,
>   			   struct pipe_resource *dst,
>   			   unsigned dst_level,
>   			   struct pipe_resource *src,
>   			   unsigned src_level,
>   			   unsigned dstx, unsigned dsty, unsigned dstz,
>   			   const struct pipe_box *src_box);
> diff --git a/src/gallium/drivers/radeonsi/si_test_dma.c b/src/gallium/drivers/radeonsi/si_test_dma.c
> index 90a2032cd80..7e396e671be 100644
> --- a/src/gallium/drivers/radeonsi/si_test_dma.c
> +++ b/src/gallium/drivers/radeonsi/si_test_dma.c
> @@ -302,21 +302,21 @@ void si_test_dma(struct si_screen *sscreen)
>   		       tsrc.width0, tsrc.height0, tsrc.array_size,
>   		       array_mode_to_string(sscreen, &ssrc->surface), bpp);
>   		fflush(stdout);
>   
>   		/* set src pixels */
>   		set_random_pixels(ctx, src, &src_cpu);
>   
>   		/* clear dst pixels */
>   		uint32_t zero = 0;
>   		si_clear_buffer(sctx, dst, 0, sdst->surface.surf_size, &zero, 4,
> -		                SI_COHERENCY_SHADER);
> +		                SI_COHERENCY_SHADER, false);
>   		memset(dst_cpu.ptr, 0, dst_cpu.layer_stride * tdst.array_size);
>   
>   		/* preparation */
>   		max_width = MIN2(tsrc.width0, tdst.width0);
>   		max_height = MIN2(tsrc.height0, tdst.height0);
>   		max_depth = MIN2(tsrc.array_size, tdst.array_size);
>   
>   		num = do_partial_copies ? num_partial_copies : 1;
>   		for (j = 0; j < num; j++) {
>   			int width, height, depth;


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