Mesa (master): aco/ngg: Implement NGG VS and TES.

GitLab Mirror gitlab-mirror at kemper.freedesktop.org
Tue Apr 7 11:44:57 UTC 2020


Module: Mesa
Branch: master
Commit: c633edad72dbc65fb8ba30a623163fcf1840361a
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=c633edad72dbc65fb8ba30a623163fcf1840361a

Author: Timur Kristóf <timur.kristof at gmail.com>
Date:   Wed Apr  1 12:29:30 2020 +0200

aco/ngg: Implement NGG VS and TES.

When NGG is used, vertex and tess eval shaders are executed on the
hardware NGG geometry stage. There is a series of steps they
must perform:

* Request GS space using GS_ALLOC_REQ
* Export the primitive
* Finally, export the normal VS outputs

In this commit, two modes are implemented:

* "late" which matches what the RADV LLVM backend currently does
* "early" which is an optimized version as seen in radeonsi

Vulkan doesn't allow the shader to write the edge flags, so we can
currently always use the "early" mode.

Exporting the primitive ID is also supported by having the GS threads
write that into LDS and reading them from LDS in the ES threads.

Signed-off-by: Timur Kristóf <timur.kristof at gmail.com>
Reviewed-by: Rhys Perry <pendingchaos02 at gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/3576>

---

 src/amd/compiler/aco_instruction_selection.cpp     | 274 ++++++++++++++++++++-
 .../compiler/aco_instruction_selection_setup.cpp   |   7 +
 2 files changed, 270 insertions(+), 11 deletions(-)

diff --git a/src/amd/compiler/aco_instruction_selection.cpp b/src/amd/compiler/aco_instruction_selection.cpp
index 6128878c83e..f287679cb23 100644
--- a/src/amd/compiler/aco_instruction_selection.cpp
+++ b/src/amd/compiler/aco_instruction_selection.cpp
@@ -3792,6 +3792,8 @@ void visit_store_output(isel_context *ctx, nir_intrinsic_instr *instr)
    if (ctx->stage == vertex_vs ||
        ctx->stage == tess_eval_vs ||
        ctx->stage == fragment_fs ||
+       ctx->stage == ngg_vertex_gs ||
+       ctx->stage == ngg_tess_eval_gs ||
        ctx->shader->info.stage == MESA_SHADER_GEOMETRY) {
       bool stored_to_temps = store_output_to_temps(ctx, instr);
       if (!stored_to_temps) {
@@ -9506,9 +9508,11 @@ static bool export_vs_varying(isel_context *ctx, int slot, bool is_pos, int *nex
 {
    assert(ctx->stage == vertex_vs ||
           ctx->stage == tess_eval_vs ||
-          ctx->stage == gs_copy_vs);
+          ctx->stage == gs_copy_vs ||
+          ctx->stage == ngg_vertex_gs ||
+          ctx->stage == ngg_tess_eval_gs);
 
-   int offset = ctx->stage == tess_eval_vs
+   int offset = (ctx->stage & sw_tes)
                 ? ctx->program->info->tes.outinfo.vs_output_param_offset[slot]
                 : ctx->program->info->vs.outinfo.vs_output_param_offset[slot];
    uint64_t mask = ctx->outputs.mask[slot];
@@ -9576,17 +9580,46 @@ static void export_vs_psiz_layer_viewport(isel_context *ctx, int *next_pos)
    ctx->block->instructions.emplace_back(std::move(exp));
 }
 
+static void create_export_phis(isel_context *ctx)
+{
+   /* Used when exports are needed, but the output temps are defined in a preceding block.
+    * This function will set up phis in order to access the outputs in the next block.
+    */
+
+   assert(ctx->block->instructions.back()->opcode == aco_opcode::p_logical_start);
+   aco_ptr<Instruction> logical_start = aco_ptr<Instruction>(ctx->block->instructions.back().release());
+   ctx->block->instructions.pop_back();
+
+   Builder bld(ctx->program, ctx->block);
+
+   for (unsigned slot = 0; slot <= VARYING_SLOT_VAR31; ++slot) {
+      uint64_t mask = ctx->outputs.mask[slot];
+      for (unsigned i = 0; i < 4; ++i) {
+         if (!(mask & (1 << i)))
+            continue;
+
+         Temp old = ctx->outputs.temps[slot * 4 + i];
+         Temp phi = bld.pseudo(aco_opcode::p_phi, bld.def(v1), old, Operand(v1));
+         ctx->outputs.temps[slot * 4 + i] = phi;
+      }
+   }
+
+   bld.insert(std::move(logical_start));
+}
+
 static void create_vs_exports(isel_context *ctx)
 {
    assert(ctx->stage == vertex_vs ||
           ctx->stage == tess_eval_vs ||
-          ctx->stage == gs_copy_vs);
+          ctx->stage == gs_copy_vs ||
+          ctx->stage == ngg_vertex_gs ||
+          ctx->stage == ngg_tess_eval_gs);
 
-   radv_vs_output_info *outinfo = ctx->stage == tess_eval_vs
+   radv_vs_output_info *outinfo = (ctx->stage & sw_tes)
                                   ? &ctx->program->info->tes.outinfo
                                   : &ctx->program->info->vs.outinfo;
 
-   if (outinfo->export_prim_id) {
+   if (outinfo->export_prim_id && !(ctx->stage & hw_ngg_gs)) {
       ctx->outputs.mask[VARYING_SLOT_PRIMITIVE_ID] |= 0x1;
       ctx->outputs.temps[VARYING_SLOT_PRIMITIVE_ID * 4u] = get_arg(ctx, ctx->args->vs_prim_id);
    }
@@ -9616,7 +9649,8 @@ static void create_vs_exports(isel_context *ctx)
    }
 
    for (unsigned i = 0; i <= VARYING_SLOT_VAR31; ++i) {
-      if (i < VARYING_SLOT_VAR0 && i != VARYING_SLOT_LAYER &&
+      if (i < VARYING_SLOT_VAR0 &&
+          i != VARYING_SLOT_LAYER &&
           i != VARYING_SLOT_PRIMITIVE_ID)
          continue;
 
@@ -10279,6 +10313,208 @@ Temp merged_wave_info_to_mask(isel_context *ctx, unsigned i)
    return cond;
 }
 
+bool ngg_early_prim_export(isel_context *ctx)
+{
+   /* TODO: Check edge flags, and if they are written, return false. (Needed for OpenGL, not for Vulkan.) */
+   return true;
+}
+
+void ngg_emit_sendmsg_gs_alloc_req(isel_context *ctx)
+{
+   Builder bld(ctx->program, ctx->block);
+
+   /* Get the id of the current wave within the threadgroup (workgroup) */
+   Builder::Result wave_id_in_tg = bld.sop2(aco_opcode::s_bfe_u32, bld.def(s1), bld.def(s1, scc),
+                                            get_arg(ctx, ctx->args->merged_wave_info), Operand(24u | (4u << 16)));
+
+   /* Execute the following code only on the first wave (wave id 0),
+    * use the SCC def to tell if the wave id is zero or not.
+    */
+   Temp cond = wave_id_in_tg.def(1).getTemp();
+   if_context ic;
+   begin_uniform_if_then(ctx, &ic, cond);
+   begin_uniform_if_else(ctx, &ic);
+   bld.reset(ctx->block);
+
+   /* Number of vertices output by VS/TES */
+   Temp vtx_cnt = bld.sop2(aco_opcode::s_bfe_u32, bld.def(s1), bld.def(s1, scc),
+                           get_arg(ctx, ctx->args->gs_tg_info), Operand(12u | (9u << 16u)));
+   /* Number of primitives output by VS/TES */
+   Temp prm_cnt = bld.sop2(aco_opcode::s_bfe_u32, bld.def(s1), bld.def(s1, scc),
+                           get_arg(ctx, ctx->args->gs_tg_info), Operand(22u | (9u << 16u)));
+
+   /* Put the number of vertices and primitives into m0 for the GS_ALLOC_REQ */
+   Temp tmp = bld.sop2(aco_opcode::s_lshl_b32, bld.def(s1), bld.def(s1, scc), prm_cnt, Operand(12u));
+   tmp = bld.sop2(aco_opcode::s_or_b32, bld.m0(bld.def(s1)), bld.def(s1, scc), tmp, vtx_cnt);
+
+   /* Request the SPI to allocate space for the primitives and vertices that will be exported by the threadgroup. */
+   bld.sopp(aco_opcode::s_sendmsg, bld.m0(tmp), -1, sendmsg_gs_alloc_req);
+
+   end_uniform_if(ctx, &ic);
+}
+
+Temp ngg_get_prim_exp_arg(isel_context *ctx, unsigned num_vertices, const Temp vtxindex[])
+{
+   Builder bld(ctx->program, ctx->block);
+
+   if (ctx->args->options->key.vs_common_out.as_ngg_passthrough) {
+      return get_arg(ctx, ctx->args->gs_vtx_offset[0]);
+   }
+
+   Temp gs_invocation_id = get_arg(ctx, ctx->args->ac.gs_invocation_id);
+   Temp tmp;
+
+   for (unsigned i = 0; i < num_vertices; ++i) {
+      assert(vtxindex[i].id());
+
+      if (i)
+         tmp = bld.vop3(aco_opcode::v_lshl_add_u32, bld.def(v1), vtxindex[i], Operand(10u * i), tmp);
+      else
+         tmp = vtxindex[i];
+
+      /* The initial edge flag is always false in tess eval shaders. */
+      if (ctx->stage == ngg_vertex_gs) {
+         Temp edgeflag = bld.vop3(aco_opcode::v_bfe_u32, bld.def(v1), gs_invocation_id, Operand(8 + i), Operand(1u));
+         tmp = bld.vop3(aco_opcode::v_lshl_add_u32, bld.def(v1), edgeflag, Operand(10u * i + 9u), tmp);
+      }
+   }
+
+   /* TODO: Set isnull field in case of merged NGG VS+GS. */
+
+   return tmp;
+}
+
+void ngg_emit_prim_export(isel_context *ctx, unsigned num_vertices_per_primitive, const Temp vtxindex[])
+{
+   Builder bld(ctx->program, ctx->block);
+   Temp prim_exp_arg = ngg_get_prim_exp_arg(ctx, num_vertices_per_primitive, vtxindex);
+
+   bld.exp(aco_opcode::exp, prim_exp_arg, Operand(v1), Operand(v1), Operand(v1),
+        1 /* enabled mask */, V_008DFC_SQ_EXP_PRIM /* dest */,
+        false /* compressed */, true/* done */, false /* valid mask */);
+}
+
+void ngg_emit_nogs_gsthreads(isel_context *ctx)
+{
+   /* Emit the things that NGG GS threads need to do, for shaders that don't have SW GS.
+    * These must always come before VS exports.
+    *
+    * It is recommended to do these as early as possible. They can be at the beginning when
+    * there is no SW GS and the shader doesn't write edge flags.
+    */
+
+   if_context ic;
+   Temp is_gs_thread = merged_wave_info_to_mask(ctx, 1);
+   begin_divergent_if_then(ctx, &ic, is_gs_thread);
+
+   Builder bld(ctx->program, ctx->block);
+   constexpr unsigned max_vertices_per_primitive = 3;
+   unsigned num_vertices_per_primitive = max_vertices_per_primitive;
+
+   if (ctx->stage == ngg_vertex_gs) {
+      /* TODO: optimize for points & lines */
+   } else if (ctx->stage == ngg_tess_eval_gs) {
+      if (ctx->shader->info.tess.point_mode)
+         num_vertices_per_primitive = 1;
+      else if (ctx->shader->info.tess.primitive_mode == GL_ISOLINES)
+         num_vertices_per_primitive = 2;
+   } else {
+      unreachable("Unsupported NGG shader stage");
+   }
+
+   Temp vtxindex[max_vertices_per_primitive];
+   vtxindex[0] = bld.vop2(aco_opcode::v_and_b32, bld.def(v1), Operand(0xffffu),
+                          get_arg(ctx, ctx->args->gs_vtx_offset[0]));
+   vtxindex[1] = num_vertices_per_primitive < 2 ? Temp(0, v1) :
+                 bld.vop3(aco_opcode::v_bfe_u32, bld.def(v1),
+                          get_arg(ctx, ctx->args->gs_vtx_offset[0]), Operand(16u), Operand(16u));
+   vtxindex[2] = num_vertices_per_primitive < 3 ? Temp(0, v1) :
+                 bld.vop2(aco_opcode::v_and_b32, bld.def(v1), Operand(0xffffu),
+                          get_arg(ctx, ctx->args->gs_vtx_offset[2]));
+
+   /* Export primitive data to the index buffer. */
+   ngg_emit_prim_export(ctx, num_vertices_per_primitive, vtxindex);
+
+   /* Export primitive ID. */
+   if (ctx->stage == ngg_vertex_gs && ctx->args->options->key.vs_common_out.export_prim_id) {
+      /* Copy Primitive IDs from GS threads to the LDS address corresponding to the ES thread of the provoking vertex. */
+      Temp prim_id = get_arg(ctx, ctx->args->ac.gs_prim_id);
+      Temp provoking_vtx_index = vtxindex[0];
+      Temp addr = bld.v_mul_imm(bld.def(v1), provoking_vtx_index, 4u);
+
+      store_lds(ctx, 4, prim_id, 0x1u, addr, 0u, 4u);
+   }
+
+   begin_divergent_if_else(ctx, &ic);
+   end_divergent_if(ctx, &ic);
+}
+
+void ngg_emit_nogs_output(isel_context *ctx)
+{
+   /* Emits NGG GS output, for stages that don't have SW GS. */
+
+   if_context ic;
+   Builder bld(ctx->program, ctx->block);
+   bool late_prim_export = !ngg_early_prim_export(ctx);
+
+   /* NGG streamout is currently disabled by default. */
+   assert(!ctx->args->shader_info->so.num_outputs);
+
+   if (late_prim_export) {
+      /* VS exports are output to registers in a predecessor block. Emit phis to get them into this block. */
+      create_export_phis(ctx);
+      /* Do what we need to do in the GS threads. */
+      ngg_emit_nogs_gsthreads(ctx);
+
+      /* What comes next should be executed on ES threads. */
+      Temp is_es_thread = merged_wave_info_to_mask(ctx, 0);
+      begin_divergent_if_then(ctx, &ic, is_es_thread);
+      bld.reset(ctx->block);
+   }
+
+   /* Export VS outputs */
+   ctx->block->kind |= block_kind_export_end;
+   create_vs_exports(ctx);
+
+   /* Export primitive ID */
+   if (ctx->args->options->key.vs_common_out.export_prim_id) {
+      Temp prim_id;
+
+      if (ctx->stage == ngg_vertex_gs) {
+         /* Wait for GS threads to store primitive ID in LDS. */
+         bld.barrier(aco_opcode::p_memory_barrier_shared);
+         bld.sopp(aco_opcode::s_barrier);
+
+         /* Calculate LDS address where the GS threads stored the primitive ID. */
+         Temp wave_id_in_tg = bld.sop2(aco_opcode::s_bfe_u32, bld.def(s1), bld.def(s1, scc),
+                                       get_arg(ctx, ctx->args->merged_wave_info), Operand(24u | (4u << 16)));
+         Temp thread_id_in_wave = emit_mbcnt(ctx, bld.def(v1));
+         Temp wave_id_mul = bld.v_mul_imm(bld.def(v1), as_vgpr(ctx, wave_id_in_tg), ctx->program->wave_size);
+         Temp thread_id_in_tg = bld.vadd32(bld.def(v1), Operand(wave_id_mul), Operand(thread_id_in_wave));
+         Temp addr = bld.v_mul_imm(bld.def(v1), thread_id_in_tg, 4u);
+
+         /* Load primitive ID from LDS. */
+         prim_id = load_lds(ctx, 4, bld.tmp(v1), addr, 0u, 4u);
+      } else if (ctx->stage == ngg_tess_eval_gs) {
+         /* TES: Just use the patch ID as the primitive ID. */
+         prim_id = get_arg(ctx, ctx->args->ac.tes_patch_id);
+      } else {
+         unreachable("unsupported NGG shader stage.");
+      }
+
+      ctx->outputs.mask[VARYING_SLOT_PRIMITIVE_ID] |= 0x1;
+      ctx->outputs.temps[VARYING_SLOT_PRIMITIVE_ID * 4u] = prim_id;
+
+      export_vs_varying(ctx, VARYING_SLOT_PRIMITIVE_ID, false, nullptr);
+   }
+
+   if (late_prim_export) {
+      begin_divergent_if_else(ctx, &ic);
+      end_divergent_if(ctx, &ic);
+      bld.reset(ctx->block);
+   }
+}
+
 void select_program(Program *program,
                     unsigned shader_count,
                     struct nir_shader *const *shaders,
@@ -10287,6 +10523,7 @@ void select_program(Program *program,
 {
    isel_context ctx = setup_isel_context(program, shader_count, shaders, config, args, false);
    if_context ic_merged_wave_info;
+   bool ngg_no_gs = ctx.stage == ngg_vertex_gs || ctx.stage == ngg_tess_eval_gs;
 
    for (unsigned i = 0; i < shader_count; i++) {
       nir_shader *nir = shaders[i];
@@ -10305,6 +10542,13 @@ void select_program(Program *program,
          split_arguments(&ctx, startpgm);
       }
 
+      if (ngg_no_gs) {
+         ngg_emit_sendmsg_gs_alloc_req(&ctx);
+
+         if (ngg_early_prim_export(&ctx))
+            ngg_emit_nogs_gsthreads(&ctx);
+      }
+
       /* In a merged VS+TCS HS, the VS implementation can be completely empty. */
       nir_function_impl *func = nir_shader_get_entrypoint(nir);
       bool empty_shader = nir_cf_list_is_empty_block(&func->body) &&
@@ -10313,7 +10557,7 @@ void select_program(Program *program,
                            (nir->info.stage == MESA_SHADER_TESS_EVAL &&
                             ctx.stage == tess_eval_geometry_gs));
 
-      bool check_merged_wave_info = ctx.tcs_in_out_eq ? i == 0 : (shader_count >= 2 && !empty_shader);
+      bool check_merged_wave_info = ctx.tcs_in_out_eq ? i == 0 : ((shader_count >= 2 && !empty_shader) || ngg_no_gs);
       bool endif_merged_wave_info = ctx.tcs_in_out_eq ? i == 1 : check_merged_wave_info;
       if (check_merged_wave_info) {
          Temp cond = merged_wave_info_to_mask(&ctx, i);
@@ -10337,11 +10581,14 @@ void select_program(Program *program,
 
       visit_cf_list(&ctx, &func->body);
 
-      if (ctx.program->info->so.num_outputs && (ctx.stage == vertex_vs || ctx.stage == tess_eval_vs))
+      if (ctx.program->info->so.num_outputs && (ctx.stage & hw_vs))
          emit_streamout(&ctx, 0);
 
-      if (ctx.stage == vertex_vs || ctx.stage == tess_eval_vs) {
+      if (ctx.stage & hw_vs) {
          create_vs_exports(&ctx);
+         ctx.block->kind |= block_kind_export_end;
+      } else if (ngg_no_gs && ngg_early_prim_export(&ctx)) {
+         ngg_emit_nogs_output(&ctx);
       } else if (nir->info.stage == MESA_SHADER_GEOMETRY) {
          Builder bld(ctx.program, ctx.block);
          bld.barrier(aco_opcode::p_memory_barrier_gs_data);
@@ -10350,14 +10597,19 @@ void select_program(Program *program,
          write_tcs_tess_factors(&ctx);
       }
 
-      if (ctx.stage == fragment_fs)
+      if (ctx.stage == fragment_fs) {
          create_fs_exports(&ctx);
+         ctx.block->kind |= block_kind_export_end;
+      }
 
       if (endif_merged_wave_info) {
          begin_divergent_if_else(&ctx, &ic_merged_wave_info);
          end_divergent_if(&ctx, &ic_merged_wave_info);
       }
 
+      if (ngg_no_gs && !ngg_early_prim_export(&ctx))
+         ngg_emit_nogs_output(&ctx);
+
       ralloc_free(ctx.divergent_vals);
 
       if (i == 0 && ctx.stage == vertex_tess_control_hs && ctx.tcs_in_out_eq) {
@@ -10370,7 +10622,7 @@ void select_program(Program *program,
    program->config->float_mode = program->blocks[0].fp_mode.val;
 
    append_logical_end(ctx.block);
-   ctx.block->kind |= block_kind_uniform | block_kind_export_end;
+   ctx.block->kind |= block_kind_uniform;
    Builder bld(ctx.program, ctx.block);
    if (ctx.program->wb_smem_l1_on_end)
       bld.smem(aco_opcode::s_dcache_wb, false);
diff --git a/src/amd/compiler/aco_instruction_selection_setup.cpp b/src/amd/compiler/aco_instruction_selection_setup.cpp
index 68f218e6391..194247eccb3 100644
--- a/src/amd/compiler/aco_instruction_selection_setup.cpp
+++ b/src/amd/compiler/aco_instruction_selection_setup.cpp
@@ -819,6 +819,13 @@ setup_vs_variables(isel_context *ctx, nir_shader *nir)
       /* radv_es_output_info *outinfo = &ctx->program->info->vs.es_info;
       outinfo->esgs_itemsize = util_bitcount64(ctx->output_masks[nir->info.stage]) * 16u; */
    }
+
+   if (ctx->stage == ngg_vertex_gs && ctx->args->options->key.vs_common_out.export_prim_id) {
+      /* We need to store the primitive IDs in LDS */
+      unsigned lds_size = ctx->program->info->ngg_info.esgs_ring_size;
+      ctx->program->config->lds_size = (lds_size + ctx->program->lds_alloc_granule - 1) /
+                                       ctx->program->lds_alloc_granule;
+   }
 }
 
 void setup_gs_variables(isel_context *ctx, nir_shader *nir)



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