From 147e71242ce539ff28e282f009c332818c35f5ac Mon Sep 17 00:00:00 2001 From: Francisco Jerez Date: Sun, 9 Apr 2017 17:28:58 -0700 Subject: [PATCH] i965/fs: Take into account lower frequency of conditional blocks in spilling cost heuristic. The individual branches of an if/else/endif construct will be executed some unknown number of times between 0 and 1 relative to the parent block. Use some factor in between as weight while approximating the cost of spill/fill instructions within a conditional if-else branch. This favors spilling registers used within conditional branches which are likely to be executed less frequently than registers used at the top level. Improves the framerate of the SynMark2 OglCSDof benchmark by ~1.9x on my SKL GT4e. Should have a comparable effect on other platforms. No significant regressions. Reviewed-by: Jason Ekstrand Reviewed-by: Kenneth Graunke Reviewed-by: Matt Turner --- src/intel/compiler/brw_fs_reg_allocate.cpp | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-) diff --git a/src/intel/compiler/brw_fs_reg_allocate.cpp b/src/intel/compiler/brw_fs_reg_allocate.cpp index 5c6f3d490f0..c981d72e4f2 100644 --- a/src/intel/compiler/brw_fs_reg_allocate.cpp +++ b/src/intel/compiler/brw_fs_reg_allocate.cpp @@ -806,7 +806,7 @@ emit_spill(const fs_builder &bld, fs_reg src, int fs_visitor::choose_spill_reg(struct ra_graph *g) { - float loop_scale = 1.0; + float block_scale = 1.0; float spill_costs[this->alloc.count]; bool no_spill[this->alloc.count]; @@ -822,23 +822,32 @@ fs_visitor::choose_spill_reg(struct ra_graph *g) foreach_block_and_inst(block, fs_inst, inst, cfg) { for (unsigned int i = 0; i < inst->sources; i++) { if (inst->src[i].file == VGRF) - spill_costs[inst->src[i].nr] += loop_scale; + spill_costs[inst->src[i].nr] += block_scale; } if (inst->dst.file == VGRF) spill_costs[inst->dst.nr] += DIV_ROUND_UP(inst->size_written, REG_SIZE) - * loop_scale; + * block_scale; switch (inst->opcode) { case BRW_OPCODE_DO: - loop_scale *= 10; + block_scale *= 10; break; case BRW_OPCODE_WHILE: - loop_scale /= 10; + block_scale /= 10; break; + case BRW_OPCODE_IF: + case BRW_OPCODE_IFF: + block_scale *= 0.5; + break; + + case BRW_OPCODE_ENDIF: + block_scale /= 0.5; + break; + case SHADER_OPCODE_GEN4_SCRATCH_WRITE: if (inst->src[0].file == VGRF) no_spill[inst->src[0].nr] = true; -- 2.30.2