[Mesa-dev] [PATCH] radeonsi: support ARB_compute_variable_group_size

Nicolai Hähnle nhaehnle at gmail.com
Fri Oct 7 17:05:36 UTC 2016


From: Nicolai Hähnle <nicolai.haehnle at amd.com>

Not sure if it's possible to avoid programming the block size twice (once for
the userdata and once for the dispatch).
---
 docs/features.txt                             |  2 +-
 docs/relnotes/12.1.0.html                     |  2 +-
 src/gallium/drivers/radeon/r600_pipe_common.c | 10 +++++-
 src/gallium/drivers/radeon/r600_pipe_common.h |  2 ++
 src/gallium/drivers/radeonsi/si_compute.c     | 10 +++++-
 src/gallium/drivers/radeonsi/si_shader.c      | 44 ++++++++++++++++++---------
 src/gallium/drivers/radeonsi/si_shader.h      |  4 ++-
 7 files changed, 55 insertions(+), 19 deletions(-)

diff --git a/docs/features.txt b/docs/features.txt
index 08b5892..8917a2e 100644
--- a/docs/features.txt
+++ b/docs/features.txt
@@ -272,21 +272,21 @@ GLES3.2, GLSL ES 3.2 -- all DONE: i965/gen9+
   GL_OES_texture_border_clamp                           DONE (all drivers)
   GL_OES_texture_buffer                                 DONE (i965, nvc0, radeonsi)
   GL_OES_texture_cube_map_array                         DONE (i965/gen8+, nvc0, radeonsi)
   GL_OES_texture_stencil8                               DONE (all drivers that support GL_ARB_texture_stencil8)
   GL_OES_texture_storage_multisample_2d_array           DONE (all drivers that support GL_ARB_texture_multisample)
 
 Khronos, ARB, and OES extensions that are not part of any OpenGL or OpenGL ES version:
 
   GL_ARB_bindless_texture                               started (airlied)
   GL_ARB_cl_event                                       not started
-  GL_ARB_compute_variable_group_size                    DONE (nvc0)
+  GL_ARB_compute_variable_group_size                    DONE (nvc0, radeonsi)
   GL_ARB_ES3_2_compatibility                            DONE (i965/gen8+)
   GL_ARB_fragment_shader_interlock                      not started
   GL_ARB_gl_spirv                                       not started
   GL_ARB_gpu_shader_int64                               started (airlied for core and Gallium, idr for i965)
   GL_ARB_indirect_parameters                            DONE (nvc0, radeonsi)
   GL_ARB_parallel_shader_compile                        not started, but Chia-I Wu did some related work in 2014
   GL_ARB_pipeline_statistics_query                      DONE (i965, nvc0, radeonsi, softpipe, swr)
   GL_ARB_post_depth_coverage                            not started
   GL_ARB_robustness_isolation                           not started
   GL_ARB_sample_locations                               not started
diff --git a/docs/relnotes/12.1.0.html b/docs/relnotes/12.1.0.html
index 43af1a5..20fd2cb 100644
--- a/docs/relnotes/12.1.0.html
+++ b/docs/relnotes/12.1.0.html
@@ -42,21 +42,21 @@ TBD.
 <p>
 Note: some of the new features are only available with certain drivers.
 </p>
 
 <ul>
 <li>OpenGL ES 3.1 on i965/hsw</li>
 <li>OpenGL ES 3.2 on i965/gen9+ (Skylake and later)</li>
 <li>GL_ARB_ES3_1_compatibility on i965</li>
 <li>GL_ARB_ES3_2_compatibility on i965/gen8+</li>
 <li>GL_ARB_clear_texture on r600, radeonsi</li>
-<li>GL_ARB_compute_variable_group_size on nvc0</li>
+<li>GL_ARB_compute_variable_group_size on nvc0, radeonsi</li>
 <li>GL_ARB_cull_distance on radeonsi</li>
 <li>GL_ARB_enhanced_layouts on i965, radeonsi, llvmpipe, softpipe</li>
 <li>GL_ARB_indirect_parameters on radeonsi</li>
 <li>GL_ARB_query_buffer_object on radeonsi</li>
 <li>GL_ARB_shader_draw_parameters on radeonsi</li>
 <li>GL_ARB_shader_group_vote on nvc0</li>
 <li>GL_ARB_shader_viewport_layer_array on i965/gen6+</li>
 <li>GL_ARB_stencil_texturing on i965/hsw</li>
 <li>GL_ARB_texture_stencil8 on i965/hsw</li>
 <li>GL_EXT_window_rectangles on nv50, nvc0</li>
diff --git a/src/gallium/drivers/radeon/r600_pipe_common.c b/src/gallium/drivers/radeon/r600_pipe_common.c
index 44863ee..3dbcbc6 100644
--- a/src/gallium/drivers/radeon/r600_pipe_common.c
+++ b/src/gallium/drivers/radeon/r600_pipe_common.c
@@ -1030,21 +1030,29 @@ static int r600_get_compute_param(struct pipe_screen *screen,
 		return sizeof(uint32_t);
 	case PIPE_COMPUTE_CAP_MAX_PRIVATE_SIZE:
 		break; /* unused */
 	case PIPE_COMPUTE_CAP_SUBGROUP_SIZE:
 		if (ret) {
 			uint32_t *subgroup_size = ret;
 			*subgroup_size = r600_wavefront_size(rscreen->family);
 		}
 		return sizeof(uint32_t);
 	case PIPE_COMPUTE_CAP_MAX_VARIABLE_THREADS_PER_BLOCK:
-		return 0;
+		if (ret) {
+			uint64_t *max_variable_threads_per_block = ret;
+			if (rscreen->chip_class >= SI && HAVE_LLVM >= 0x309 &&
+			    ir_type == PIPE_SHADER_IR_TGSI)
+				*max_variable_threads_per_block = SI_MAX_VARIABLE_THREADS_PER_BLOCK;
+			else
+				*max_variable_threads_per_block = 0;
+		}
+		return sizeof(uint64_t);
 	}
 
         fprintf(stderr, "unknown PIPE_COMPUTE_CAP %d\n", param);
         return 0;
 }
 
 static uint64_t r600_get_timestamp(struct pipe_screen *screen)
 {
 	struct r600_common_screen *rscreen = (struct r600_common_screen*)screen;
 
diff --git a/src/gallium/drivers/radeon/r600_pipe_common.h b/src/gallium/drivers/radeon/r600_pipe_common.h
index 54991e8..290b228 100644
--- a/src/gallium/drivers/radeon/r600_pipe_common.h
+++ b/src/gallium/drivers/radeon/r600_pipe_common.h
@@ -99,20 +99,22 @@
 #define DBG_NO_RB_PLUS		(1llu << 45)
 #define DBG_SI_SCHED		(1llu << 46)
 #define DBG_MONOLITHIC_SHADERS	(1llu << 47)
 #define DBG_NO_CE		(1llu << 48)
 #define DBG_UNSAFE_MATH		(1llu << 49)
 #define DBG_NO_DCC_FB		(1llu << 50)
 
 #define R600_MAP_BUFFER_ALIGNMENT 64
 #define R600_MAX_VIEWPORTS        16
 
+#define SI_MAX_VARIABLE_THREADS_PER_BLOCK 1024
+
 enum r600_coherency {
 	R600_COHERENCY_NONE, /* no cache flushes needed */
 	R600_COHERENCY_SHADER,
 	R600_COHERENCY_CB_META,
 };
 
 #ifdef PIPE_ARCH_BIG_ENDIAN
 #define R600_BIG_ENDIAN 1
 #else
 #define R600_BIG_ENDIAN 0
diff --git a/src/gallium/drivers/radeonsi/si_compute.c b/src/gallium/drivers/radeonsi/si_compute.c
index 1d1df2f..e59bafe 100644
--- a/src/gallium/drivers/radeonsi/si_compute.c
+++ b/src/gallium/drivers/radeonsi/si_compute.c
@@ -594,25 +594,33 @@ static void si_setup_tgsi_grid(struct si_context *sctx,
 		for (i = 0; i < 3; ++i) {
 			radeon_emit(cs, PKT3(PKT3_COPY_DATA, 4, 0));
 			radeon_emit(cs, COPY_DATA_SRC_SEL(COPY_DATA_MEM) |
 					COPY_DATA_DST_SEL(COPY_DATA_REG));
 			radeon_emit(cs, (va +  4 * i));
 			radeon_emit(cs, (va + 4 * i) >> 32);
 			radeon_emit(cs, (grid_size_reg >> 2) + i);
 			radeon_emit(cs, 0);
 		}
 	} else {
+		struct si_compute *program = sctx->cs_shader_state.program;
+		bool variable_group_size =
+			program->shader.selector->info.properties[TGSI_PROPERTY_CS_FIXED_BLOCK_WIDTH] == 0;
 
-		radeon_set_sh_reg_seq(cs, grid_size_reg, 3);
+		radeon_set_sh_reg_seq(cs, grid_size_reg, variable_group_size ? 6 : 3);
 		radeon_emit(cs, info->grid[0]);
 		radeon_emit(cs, info->grid[1]);
 		radeon_emit(cs, info->grid[2]);
+		if (variable_group_size) {
+			radeon_emit(cs, info->block[0]);
+			radeon_emit(cs, info->block[1]);
+			radeon_emit(cs, info->block[2]);
+		}
 	}
 }
 
 static void si_emit_dispatch_packets(struct si_context *sctx,
                                      const struct pipe_grid_info *info)
 {
 	struct radeon_winsys_cs *cs = sctx->b.gfx.cs;
 	bool render_cond_bit = sctx->b.render_cond && !sctx->b.render_cond_force_off;
 	unsigned waves_per_threadgroup =
 		DIV_ROUND_UP(info->block[0] * info->block[1] * info->block[2], 64);
diff --git a/src/gallium/drivers/radeonsi/si_shader.c b/src/gallium/drivers/radeonsi/si_shader.c
index ff51c8b..49d4121 100644
--- a/src/gallium/drivers/radeonsi/si_shader.c
+++ b/src/gallium/drivers/radeonsi/si_shader.c
@@ -1763,30 +1763,35 @@ static void declare_system_value(
 
 	case TGSI_SEMANTIC_GRID_SIZE:
 		value = LLVMGetParam(radeon_bld->main_fn, SI_PARAM_GRID_SIZE);
 		break;
 
 	case TGSI_SEMANTIC_BLOCK_SIZE:
 	{
 		LLVMValueRef values[3];
 		unsigned i;
 		unsigned *properties = ctx->shader->selector->info.properties;
-		unsigned sizes[3] = {
-			properties[TGSI_PROPERTY_CS_FIXED_BLOCK_WIDTH],
-			properties[TGSI_PROPERTY_CS_FIXED_BLOCK_HEIGHT],
-			properties[TGSI_PROPERTY_CS_FIXED_BLOCK_DEPTH]
-		};
 
-		for (i = 0; i < 3; ++i)
-			values[i] = lp_build_const_int32(gallivm, sizes[i]);
+		if (properties[TGSI_PROPERTY_CS_FIXED_BLOCK_WIDTH] != 0) {
+			unsigned sizes[3] = {
+				properties[TGSI_PROPERTY_CS_FIXED_BLOCK_WIDTH],
+				properties[TGSI_PROPERTY_CS_FIXED_BLOCK_HEIGHT],
+				properties[TGSI_PROPERTY_CS_FIXED_BLOCK_DEPTH]
+			};
+
+			for (i = 0; i < 3; ++i)
+				values[i] = lp_build_const_int32(gallivm, sizes[i]);
 
-		value = lp_build_gather_values(gallivm, values, 3);
+			value = lp_build_gather_values(gallivm, values, 3);
+		} else {
+			value = LLVMGetParam(radeon_bld->main_fn, SI_PARAM_BLOCK_SIZE);
+		}
 		break;
 	}
 
 	case TGSI_SEMANTIC_BLOCK_ID:
 		value = LLVMGetParam(radeon_bld->main_fn, SI_PARAM_BLOCK_ID);
 		break;
 
 	case TGSI_SEMANTIC_THREAD_ID:
 		value = LLVMGetParam(radeon_bld->main_fn, SI_PARAM_THREAD_ID);
 		break;
@@ -5673,20 +5678,21 @@ static void create_function(struct si_shader_context *ctx)
 
 			for (i = 0; i < num_return_sgprs; i++)
 				returns[i] = ctx->i32;
 			for (; i < num_returns; i++)
 				returns[i] = ctx->f32;
 		}
 		break;
 
 	case PIPE_SHADER_COMPUTE:
 		params[SI_PARAM_GRID_SIZE] = v3i32;
+		params[SI_PARAM_BLOCK_SIZE] = v3i32;
 		params[SI_PARAM_BLOCK_ID] = v3i32;
 		last_sgpr = SI_PARAM_BLOCK_ID;
 
 		params[SI_PARAM_THREAD_ID] = v3i32;
 		num_params = SI_PARAM_THREAD_ID + 1;
 		break;
 	default:
 		assert(0 && "unimplemented shader");
 		return;
 	}
@@ -5709,21 +5715,26 @@ static void create_function(struct si_shader_context *ctx)
 					  S_0286D0_LINEAR_CENTROID_ENA(1) |
 					  S_0286D0_FRONT_FACE_ENA(1) |
 					  S_0286D0_POS_FIXED_PT_ENA(1));
 	} else if (ctx->type == PIPE_SHADER_COMPUTE) {
 		const unsigned *properties = shader->selector->info.properties;
 		unsigned max_work_group_size =
 		               properties[TGSI_PROPERTY_CS_FIXED_BLOCK_WIDTH] *
 		               properties[TGSI_PROPERTY_CS_FIXED_BLOCK_HEIGHT] *
 		               properties[TGSI_PROPERTY_CS_FIXED_BLOCK_DEPTH];
 
-		assert(max_work_group_size);
+		if (!max_work_group_size) {
+			/* This is a variable group size compute shader,
+			 * compile it for the maximum possible group size.
+			 */
+			max_work_group_size = SI_MAX_VARIABLE_THREADS_PER_BLOCK;
+		}
 
 		radeon_llvm_add_attribute(ctx->radeon_bld.main_fn,
 		                          "amdgpu-max-work-group-size",
 		                          max_work_group_size);
 	}
 
 	shader->info.num_input_sgprs = 0;
 	shader->info.num_input_vgprs = 0;
 
 	for (i = 0; i <= last_sgpr; ++i)
@@ -6646,25 +6657,30 @@ int si_compile_tgsi_shader(struct si_screen *sscreen,
 
 	/* Validate SGPR and VGPR usage for compute to detect compiler bugs.
 	 * LLVM 3.9svn has this bug.
 	 */
 	if (sel->type == PIPE_SHADER_COMPUTE) {
 		unsigned *props = sel->info.properties;
 		unsigned wave_size = 64;
 		unsigned max_vgprs = 256;
 		unsigned max_sgprs = sscreen->b.chip_class >= VI ? 800 : 512;
 		unsigned max_sgprs_per_wave = 128;
-		unsigned min_waves_per_cu =
-			DIV_ROUND_UP(props[TGSI_PROPERTY_CS_FIXED_BLOCK_WIDTH] *
-				     props[TGSI_PROPERTY_CS_FIXED_BLOCK_HEIGHT] *
-				     props[TGSI_PROPERTY_CS_FIXED_BLOCK_DEPTH],
-				     wave_size);
+		unsigned max_block_threads;
+
+		if (props[TGSI_PROPERTY_CS_FIXED_BLOCK_WIDTH])
+			max_block_threads = props[TGSI_PROPERTY_CS_FIXED_BLOCK_WIDTH] *
+					    props[TGSI_PROPERTY_CS_FIXED_BLOCK_HEIGHT] *
+					    props[TGSI_PROPERTY_CS_FIXED_BLOCK_DEPTH];
+		else
+			max_block_threads = SI_MAX_VARIABLE_THREADS_PER_BLOCK;
+
+		unsigned min_waves_per_cu = DIV_ROUND_UP(max_block_threads, wave_size);
 		unsigned min_waves_per_simd = DIV_ROUND_UP(min_waves_per_cu, 4);
 
 		max_vgprs = max_vgprs / min_waves_per_simd;
 		max_sgprs = MIN2(max_sgprs / min_waves_per_simd, max_sgprs_per_wave);
 
 		if (shader->config.num_sgprs > max_sgprs ||
 		    shader->config.num_vgprs > max_vgprs) {
 			fprintf(stderr, "LLVM failed to compile a shader correctly: "
 				"SGPR:VGPR usage is %u:%u, but the hw limit is %u:%u\n",
 				shader->config.num_sgprs, shader->config.num_vgprs,
diff --git a/src/gallium/drivers/radeonsi/si_shader.h b/src/gallium/drivers/radeonsi/si_shader.h
index 67cb67d2..f2618ac 100644
--- a/src/gallium/drivers/radeonsi/si_shader.h
+++ b/src/gallium/drivers/radeonsi/si_shader.h
@@ -122,21 +122,22 @@ enum {
 	/* GS limits */
 	SI_GS_NUM_USER_SGPR = SI_NUM_RESOURCE_SGPRS,
 	SI_GSCOPY_NUM_USER_SGPR = SI_SGPR_RW_BUFFERS_HI + 1,
 
 	/* PS only */
 	SI_SGPR_ALPHA_REF	= SI_NUM_RESOURCE_SGPRS,
 	SI_PS_NUM_USER_SGPR,
 
 	/* CS only */
 	SI_SGPR_GRID_SIZE = SI_NUM_RESOURCE_SGPRS,
-	SI_CS_NUM_USER_SGPR = SI_SGPR_GRID_SIZE + 3
+	SI_SGPR_BLOCK_SIZE = SI_SGPR_GRID_SIZE + 3,
+	SI_CS_NUM_USER_SGPR = SI_SGPR_BLOCK_SIZE + 3
 };
 
 /* LLVM function parameter indices */
 enum {
 	SI_PARAM_RW_BUFFERS,
 	SI_PARAM_CONST_BUFFERS,
 	SI_PARAM_SAMPLERS,
 	SI_PARAM_IMAGES,
 	SI_PARAM_SHADER_BUFFERS,
 	SI_NUM_RESOURCE_PARAMS,
@@ -212,20 +213,21 @@ enum {
 	SI_PARAM_POS_Y_FLOAT,
 	SI_PARAM_POS_Z_FLOAT,
 	SI_PARAM_POS_W_FLOAT,
 	SI_PARAM_FRONT_FACE,
 	SI_PARAM_ANCILLARY,
 	SI_PARAM_SAMPLE_COVERAGE,
 	SI_PARAM_POS_FIXED_PT,
 
 	/* CS only parameters */
 	SI_PARAM_GRID_SIZE = SI_NUM_RESOURCE_PARAMS,
+	SI_PARAM_BLOCK_SIZE,
 	SI_PARAM_BLOCK_ID,
 	SI_PARAM_THREAD_ID,
 
 	SI_NUM_PARAMS = SI_PARAM_POS_FIXED_PT + 9, /* +8 for COLOR[0..1] */
 };
 
 /* SI-specific system values. */
 enum {
 	TGSI_SEMANTIC_DEFAULT_TESSOUTER_SI = TGSI_SEMANTIC_COUNT,
 	TGSI_SEMANTIC_DEFAULT_TESSINNER_SI,
-- 
2.7.4



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