From: Rob Clark <robdclark@chromium.org>
Date: Wed, 4 Mar 2020 18:51:10 +0000 (-0800)
Subject: freedreno/ir3: add simplified stall estimation
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=752b9985bed171a39bb439421d0e2cd8d0ab82aa;p=mesa.git

freedreno/ir3: add simplified stall estimation

Doesn't take into account stalls that result from a register written in
a different block, etc.  But this should be more useful than just using
number of (ss)'s by trying to estimate how costly a given sync is.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4071>
---

diff --git a/src/freedreno/ir3/ir3.c b/src/freedreno/ir3/ir3.c
index 0dbe9bba460..bf842701868 100644
--- a/src/freedreno/ir3/ir3.c
+++ b/src/freedreno/ir3/ir3.c
@@ -911,6 +911,8 @@ void * ir3_assemble(struct ir3 *shader, struct ir3_info *info,
 	ptr = dwords = calloc(4, info->sizedwords);
 
 	foreach_block (block, &shader->block_list) {
+		unsigned sfu_delay = 0;
+
 		foreach_instr (instr, &block->instr_list) {
 			int ret = emit[opc_cat(instr->opc)](instr, dwords, info);
 			if (ret)
@@ -925,11 +927,19 @@ void * ir3_assemble(struct ir3 *shader, struct ir3_info *info,
 				info->nops_count += 1 + instr->repeat;
 			dwords += 2;
 
-			if (instr->flags & IR3_INSTR_SS)
+			if (instr->flags & IR3_INSTR_SS) {
 				info->ss++;
+				info->sstall += sfu_delay;
+			}
 
 			if (instr->flags & IR3_INSTR_SY)
 				info->sy++;
+
+			if (is_sfu(instr)) {
+				sfu_delay = 10;
+			} else if (sfu_delay > 0) {
+				sfu_delay--;
+			}
 		}
 	}
 
diff --git a/src/freedreno/ir3/ir3.h b/src/freedreno/ir3/ir3.h
index b66d8e2d6fd..1a3edbc4530 100644
--- a/src/freedreno/ir3/ir3.h
+++ b/src/freedreno/ir3/ir3.h
@@ -59,6 +59,9 @@ struct ir3_info {
 	/* number of sync bits: */
 	uint16_t ss, sy;
 
+	/* estimate of number of cycles stalled on (ss) */
+	uint16_t sstall;
+
 	uint16_t last_baryf;     /* instruction # of last varying fetch */
 };
 
diff --git a/src/gallium/drivers/freedreno/ir3/ir3_gallium.c b/src/gallium/drivers/freedreno/ir3/ir3_gallium.c
index 5a47376c14e..9ad67d2ec9b 100644
--- a/src/gallium/drivers/freedreno/ir3/ir3_gallium.c
+++ b/src/gallium/drivers/freedreno/ir3/ir3_gallium.c
@@ -53,7 +53,7 @@ dump_shader_info(struct ir3_shader_variant *v, bool binning_pass,
 	pipe_debug_message(debug, SHADER_INFO,
 			"%s shader: %u inst, %u nops, %u non-nops, %u dwords, "
 			"%u last-baryf, %u half, %u full, %u constlen, "
-			"%u (ss), %u (sy), %d max_sun, %d loops\n",
+			"%u sstall, %u (ss), %u (sy), %d max_sun, %d loops\n",
 			ir3_shader_stage(v),
 			v->info.instrs_count,
 			v->info.nops_count,
@@ -63,6 +63,7 @@ dump_shader_info(struct ir3_shader_variant *v, bool binning_pass,
 			v->info.max_half_reg + 1,
 			v->info.max_reg + 1,
 			v->constlen,
+			v->info.sstall,
 			v->info.ss, v->info.sy,
 			v->max_sun, v->loops);
 }