Mesa (main): radeonsi: set more precise max_waves in NGG code

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Module: Mesa
Branch: main
Commit: ce4f4a8d13c5b1b0816f6b3121131d7b63f746c2
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=ce4f4a8d13c5b1b0816f6b3121131d7b63f746c2

Author: Marek Olšák <marek.olsak at amd.com>
Date:   Mon May 24 17:23:56 2021 -0400

radeonsi: set more precise max_waves in NGG code

Acked-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer at amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11102>

---

 src/gallium/drivers/radeonsi/gfx10_shader_ngg.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/src/gallium/drivers/radeonsi/gfx10_shader_ngg.c b/src/gallium/drivers/radeonsi/gfx10_shader_ngg.c
index 8f08f27d43d..5f3763bcd83 100644
--- a/src/gallium/drivers/radeonsi/gfx10_shader_ngg.c
+++ b/src/gallium/drivers/radeonsi/gfx10_shader_ngg.c
@@ -477,7 +477,13 @@ static void build_streamout(struct si_shader_context *ctx, struct ngg_streamout
             &ctx->ac, ctx->gs_ngg_scratch, LLVMConstInt(ctx->ac.i32, 12 + 8 * stream, false));
          primemit_scan[stream].waveidx = get_wave_id_in_tg(ctx);
          primemit_scan[stream].numwaves = get_tgsize(ctx);
-         primemit_scan[stream].maxwaves = 8;
+         if (ctx->stage == MESA_SHADER_GEOMETRY) {
+            /* ngg_subgroup_size is only the input size. GS can always generate up to 256 vertices. */
+            primemit_scan[stream].maxwaves = DIV_ROUND_UP(256, ctx->ac.wave_size);
+         } else {
+            primemit_scan[stream].maxwaves = DIV_ROUND_UP(ctx->screen->ngg_subgroup_size,
+                                                          ctx->ac.wave_size);
+         }
          ac_build_wg_scan_top(&ctx->ac, &primemit_scan[stream]);
       }
    }
@@ -813,9 +819,7 @@ void gfx10_emit_ngg_culling_epilogue(struct ac_shader_abi *abi, unsigned max_out
    struct si_shader_selector *sel = shader->selector;
    struct si_shader_info *info = &sel->info;
    LLVMBuilderRef builder = ctx->ac.builder;
-   unsigned subgroup_size = ctx->screen->ngg_subgroup_size;
-   unsigned max_waves = ctx->ac.wave_size == 64 ? DIV_ROUND_UP(subgroup_size, 64) :
-                                                  DIV_ROUND_UP(subgroup_size, 32);
+   unsigned max_waves = DIV_ROUND_UP(ctx->screen->ngg_subgroup_size, ctx->ac.wave_size);
 
    assert(shader->key.opt.ngg_culling);
    assert(shader->key.as_ngg);
@@ -1864,7 +1868,7 @@ void gfx10_ngg_gs_emit_epilogue(struct si_shader_context *ctx)
    vertlive_scan.scratch = ac_build_gep0(&ctx->ac, ctx->gs_ngg_scratch, ctx->ac.i32_0);
    vertlive_scan.waveidx = get_wave_id_in_tg(ctx);
    vertlive_scan.numwaves = get_tgsize(ctx);
-   vertlive_scan.maxwaves = 8;
+   vertlive_scan.maxwaves = DIV_ROUND_UP(256, ctx->ac.wave_size);
 
    ac_build_wg_scan(&ctx->ac, &vertlive_scan);