Module: Mesa Branch: master Commit: d0e1d6b7e27bf5f05436e47080d326d7daa63af2 URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=d0e1d6b7e27bf5f05436e47080d326d7daa63af2
Author: Kenneth Graunke <[email protected]> Date: Thu Feb 4 08:10:02 2016 -0800 i965: Don't add barrier deps for FB write messages. There are never render target reads, so there are no scheduling hazards. Giving the extra flexibility to the scheduler makes it possible to do FB writes as soon as their sources are available, reducing register pressure. It also makes it possible to do the payload setup for more than one FB write message at a time, which could better hide latency. shader-db results on Skylake: total instructions in shared programs: 9110254 -> 9110211 (-0.00%) instructions in affected programs: 2898 -> 2855 (-1.48%) helped: 3 HURT: 0 LOST: 0 GAINED: 1 A reduction in instruction counts is surprising, but legitimate: the three shaders helped were spilling, and reducing register pressure allowed us to issue fewer spills/fills. total cycles in shared programs: 69035108 -> 68928820 (-0.15%) cycles in affected programs: 4412402 -> 4306114 (-2.41%) helped: 4457 HURT: 213 Signed-off-by: Kenneth Graunke <[email protected]> Reviewed-by: Matt Turner <[email protected]> Reviewed-by: Connor Abbott <[email protected]> --- src/mesa/drivers/dri/i965/brw_schedule_instructions.cpp | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/src/mesa/drivers/dri/i965/brw_schedule_instructions.cpp b/src/mesa/drivers/dri/i965/brw_schedule_instructions.cpp index 60f7fd9..4f97577 100644 --- a/src/mesa/drivers/dri/i965/brw_schedule_instructions.cpp +++ b/src/mesa/drivers/dri/i965/brw_schedule_instructions.cpp @@ -939,8 +939,9 @@ fs_instruction_scheduler::calculate_deps() foreach_in_list(schedule_node, n, &instructions) { fs_inst *inst = (fs_inst *)n->inst; - if (inst->opcode == FS_OPCODE_PLACEHOLDER_HALT || - inst->has_side_effects()) + if ((inst->opcode == FS_OPCODE_PLACEHOLDER_HALT || + inst->has_side_effects()) && + inst->opcode != FS_OPCODE_FB_WRITE) add_barrier_deps(n); /* read-after-write deps. */ @@ -1195,7 +1196,7 @@ vec4_instruction_scheduler::calculate_deps() foreach_in_list(schedule_node, n, &instructions) { vec4_instruction *inst = (vec4_instruction *)n->inst; - if (inst->has_side_effects()) + if (inst->has_side_effects() && inst->opcode != FS_OPCODE_FB_WRITE) add_barrier_deps(n); /* read-after-write deps. */ _______________________________________________ mesa-commit mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/mesa-commit
