r600g: avoid unnecessary shader exports v2

In some cases TGSI shader has more color outputs than the number of CBs,
so it seems we need to limit the number of color exports. This requires
different shader variants depending on the nr_cbufs, but on the other hand
we are doing less exports, which are very costly.

v2: fix various piglit regressions

Signed-off-by: Vadim Girlin <vadimgirlin@gmail.com>
Signed-off-by: Jerome Glisse <jglisse@redhat.com>

diff --git a/src/gallium/drivers/r600/evergreen_state.c b/src/gallium/drivers/r600/evergreen_state.c
index 4b82b06..895d8a2 100644 (file)
--- a/src/gallium/drivers/r600/evergreen_state.c
+++ b/src/gallium/drivers/r600/evergreen_state.c
@@ -2646,18 +2646,14 @@ void evergreen_pipe_shader_ps(struct pipe_context *ctx, struct r600_pipe_shader
                db_shader_control |= S_02880C_KILL_ENABLE(1);
 
        exports_ps = 0;
-       num_cout = 0;
        for (i = 0; i < rshader->noutput; i++) {
                if (rshader->output[i].name == TGSI_SEMANTIC_POSITION ||
                    rshader->output[i].name == TGSI_SEMANTIC_STENCIL)
                        exports_ps |= 1;
-               else if (rshader->output[i].name == TGSI_SEMANTIC_COLOR) {
-                       if (rshader->fs_write_all)
-                               num_cout = rshader->nr_cbufs;
-                       else
-                               num_cout++;
-               }
        }
+
+       num_cout = rshader->nr_ps_color_exports;
+
        exports_ps |= S_02884C_EXPORT_COLORS(num_cout);
        if (!exports_ps) {
                /* always at least export 1 component per pixel */

diff --git a/src/gallium/drivers/r600/r600_pipe.h b/src/gallium/drivers/r600/r600_pipe.h
index 5d194e3..380fd66 100644 (file)
--- a/src/gallium/drivers/r600/r600_pipe.h
+++ b/src/gallium/drivers/r600/r600_pipe.h
@@ -198,10 +198,7 @@ struct r600_pipe_shader_selector {
        /* PIPE_SHADER_[VERTEX|FRAGMENT|...] */
        unsigned        type;
 
-       /* 1 on evergreen+ when the shader contains
-        * TGSI_PROPERTY_FS_COLOR0_WRITES_ALL_CBUFS, otherwise it's 0.
-        * Used to determine whether we need to include nr_cbufs in the key */
-       unsigned        eg_fs_write_all;
+       unsigned        nr_ps_max_color_exports;
 };
 
 struct r600_pipe_shader {

diff --git a/src/gallium/drivers/r600/r600_shader.c b/src/gallium/drivers/r600/r600_shader.c
index f690c10..32d5a78 100644 (file)
--- a/src/gallium/drivers/r600/r600_shader.c
+++ b/src/gallium/drivers/r600/r600_shader.c
@@ -800,6 +800,12 @@ static int tgsi_declaration(struct r600_shader_ctx *ctx)
                                ctx->cv_output = i;
                                break;
                        }
+               } else if (ctx->type == TGSI_PROCESSOR_FRAGMENT) {
+                       switch (d->Semantic.Name) {
+                       case TGSI_SEMANTIC_COLOR:
+                               ctx->shader->nr_ps_max_color_exports++;
+                               break;
+                       }
                }
                break;
        case TGSI_FILE_CONSTANT:
@@ -1152,8 +1158,10 @@ static int r600_shader_from_tgsi(struct r600_context * rctx, struct r600_pipe_sh
        ctx.colors_used = 0;
        ctx.clip_vertex_write = 0;
 
+       shader->nr_ps_color_exports = 0;
+       shader->nr_ps_max_color_exports = 0;
+
        shader->two_side = (ctx.type == TGSI_PROCESSOR_FRAGMENT) && rctx->two_side;
-       shader->nr_cbufs = rctx->nr_cbufs;
 
        /* register allocations */
        /* Values [0,127] correspond to GPR[0..127].
@@ -1288,6 +1296,9 @@ static int r600_shader_from_tgsi(struct r600_context * rctx, struct r600_pipe_sh
                }
        }
 
+       if (shader->fs_write_all && rctx->chip_class >= EVERGREEN)
+               shader->nr_ps_max_color_exports = 8;
+
        if (ctx.fragcoord_input >= 0) {
                if (ctx.bc->chip_class == CAYMAN) {
                        for (j = 0 ; j < 4; j++) {
@@ -1527,10 +1538,17 @@ static int r600_shader_from_tgsi(struct r600_context * rctx, struct r600_pipe_sh
                        break;
                case TGSI_PROCESSOR_FRAGMENT:
                        if (shader->output[i].name == TGSI_SEMANTIC_COLOR) {
+                               /* never export more colors than the number of CBs */
+                               if (next_pixel_base && next_pixel_base >= (rctx->nr_cbufs + rctx->dual_src_blend * 1)) {
+                                       /* skip export */
+                                       j--;
+                                       continue;
+                               }
                                output[j].array_base = next_pixel_base++;
                                output[j].type = V_SQ_CF_ALLOC_EXPORT_WORD0_SQ_EXPORT_PIXEL;
+                               shader->nr_ps_color_exports++;
                                if (shader->fs_write_all && (rctx->chip_class >= EVERGREEN)) {
-                                       for (k = 1; k < shader->nr_cbufs; k++) {
+                                       for (k = 1; k < rctx->nr_cbufs; k++) {
                                                j++;
                                                memset(&output[j], 0, sizeof(struct r600_bytecode_output));
                                                output[j].gpr = shader->output[i].gpr;
@@ -1544,6 +1562,7 @@ static int r600_shader_from_tgsi(struct r600_context * rctx, struct r600_pipe_sh
                                                output[j].array_base = next_pixel_base++;
                                                output[j].inst = BC_INST(ctx.bc, V_SQ_CF_ALLOC_EXPORT_WORD1_SQ_CF_INST_EXPORT);
                                                output[j].type = V_SQ_CF_ALLOC_EXPORT_WORD0_SQ_EXPORT_PIXEL;
+                                               shader->nr_ps_color_exports++;
                                        }
                                }
                        } else if (shader->output[i].name == TGSI_SEMANTIC_POSITION) {
@@ -1594,7 +1613,7 @@ static int r600_shader_from_tgsi(struct r600_context * rctx, struct r600_pipe_sh
        }
 
        /* add fake pixel export */
-       if (ctx.type == TGSI_PROCESSOR_FRAGMENT && j == 0) {
+       if (ctx.type == TGSI_PROCESSOR_FRAGMENT && next_pixel_base == 0) {
                memset(&output[j], 0, sizeof(struct r600_bytecode_output));
                output[j].gpr = 0;
                output[j].elem_size = 3;

diff --git a/src/gallium/drivers/r600/r600_shader.h b/src/gallium/drivers/r600/r600_shader.h
index 2d35e77..eb0bbf6 100644 (file)
--- a/src/gallium/drivers/r600/r600_shader.h
+++ b/src/gallium/drivers/r600/r600_shader.h
@@ -49,7 +49,12 @@ struct r600_shader {
        boolean                 fs_write_all;
        boolean                 vs_prohibit_ucps;
        boolean                 two_side;
-       unsigned                nr_cbufs;
+       /* Number of color outputs in the TGSI shader,
+        * sometimes it could be higher than nr_cbufs (bug?).
+        * Also with writes_all property on eg+ it will be set to max CB number */
+       unsigned                nr_ps_max_color_exports;
+       /* Real number of ps color exports compiled in the bytecode */
+       unsigned                nr_ps_color_exports;
        /* bit n is set if the shader writes gl_ClipDistance[n] */
        unsigned                clip_dist_write;
        /* flag is set if the shader writes VS_OUT_MISC_VEC (e.g. for PSIZE) */

diff --git a/src/gallium/drivers/r600/r600_state.c b/src/gallium/drivers/r600/r600_state.c
index 295453a..d621aee 100644 (file)
--- a/src/gallium/drivers/r600/r600_state.c
+++ b/src/gallium/drivers/r600/r600_state.c
@@ -1644,6 +1644,8 @@ static void r600_set_framebuffer_state(struct pipe_context *ctx,
 
        /* build states */
        rctx->have_depth_fb = 0;
+       rctx->nr_cbufs = state->nr_cbufs;
+
        for (int i = 0; i < state->nr_cbufs; i++) {
                r600_cb(rctx, rstate, state, i);
        }

diff --git a/src/gallium/drivers/r600/r600_state_common.c b/src/gallium/drivers/r600/r600_state_common.c
index 879dcc5..6050fa0 100644 (file)
--- a/src/gallium/drivers/r600/r600_state_common.c
+++ b/src/gallium/drivers/r600/r600_state_common.c
@@ -437,9 +437,8 @@ static INLINE unsigned r600_shader_selector_key(struct pipe_context * ctx,
        unsigned key;
 
        if (sel->type == PIPE_SHADER_FRAGMENT) {
-               key = rctx->two_side;
-               if (sel->eg_fs_write_all)
-                       key |= rctx->nr_cbufs << 1;
+               key = rctx->two_side |
+                               MIN2(sel->nr_ps_max_color_exports, rctx->nr_cbufs + rctx->dual_src_blend) << 1;
        } else
                key = 0;
 
@@ -494,14 +493,12 @@ static int r600_shader_select(struct pipe_context *ctx,
                        return r;
                }
 
-               /* We don't know the value of eg_fs_write_all property until we built
-                * at least one variant, so we may need to recompute the key (include
-                * rctx->nr_cbufs) after building first variant. */
+               /* We don't know the value of nr_ps_max_color_exports until we built
+                * at least one variant, so we may need to recompute the key after
+                * building first variant. */
                if (sel->type == PIPE_SHADER_FRAGMENT &&
-                               sel->num_shaders == 0 &&
-                               rctx->chip_class >= EVERGREEN &&
-                               shader->shader.fs_write_all) {
-                       sel->eg_fs_write_all = 1;
+                               sel->num_shaders == 0) {
+                       sel->nr_ps_max_color_exports = shader->shader.nr_ps_max_color_exports;
                        key = r600_shader_selector_key(ctx, sel);
                }
 
@@ -515,9 +512,6 @@ static int r600_shader_select(struct pipe_context *ctx,
        shader->next_variant = sel->current;
        sel->current = shader;
 
-       /* Moved from r600_bind_ps_shader, different shader variants
-        * may use different number of GPRs, so we need to update it. */
-       /* FIXME: we never did it after rebuilding the shaders, is it required? */
        if (rctx->chip_class < EVERGREEN && rctx->ps_shader && rctx->vs_shader) {
                r600_adjust_gprs(rctx);
        }