Mesa (master): i965/sched: write-after-read dependencies are free
Connor Abbott
cwabbott0 at kemper.freedesktop.org
Fri Oct 30 06:20:15 UTC 2015
Module: Mesa
Branch: master
Commit: 85fce2d2f50335b1d204dbaedc36cdd37164a9c0
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=85fce2d2f50335b1d204dbaedc36cdd37164a9c0
Author: Connor Abbott <cwabbott0 at gmail.com>
Date: Sun Jun 7 00:37:27 2015 -0400
i965/sched: write-after-read dependencies are free
Although write-after-write dependencies have the same latency as
read-after-write dependencies due to how the register scoreboard works,
write-after-read dependencies aren't checked by the EU at all, so
they're purely a constraint on how the scheduler can order the
instructions.
v2: fix accumulator dependencies too.
Reviewed-by: Jason Ekstrand <jason.ekstrand at intel.com>
---
src/mesa/drivers/dri/i965/brw_schedule_instructions.cpp | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/src/mesa/drivers/dri/i965/brw_schedule_instructions.cpp b/src/mesa/drivers/dri/i965/brw_schedule_instructions.cpp
index 3e86cb0..094c47a 100644
--- a/src/mesa/drivers/dri/i965/brw_schedule_instructions.cpp
+++ b/src/mesa/drivers/dri/i965/brw_schedule_instructions.cpp
@@ -927,10 +927,10 @@ fs_instruction_scheduler::calculate_deps()
if (inst->src[i].file == GRF) {
if (post_reg_alloc) {
for (int r = 0; r < inst->regs_read(i); r++)
- add_dep(n, last_grf_write[inst->src[i].reg + r]);
+ add_dep(n, last_grf_write[inst->src[i].reg + r], 0);
} else {
for (int r = 0; r < inst->regs_read(i); r++) {
- add_dep(n, last_grf_write[inst->src[i].reg * 16 + inst->src[i].reg_offset + r]);
+ add_dep(n, last_grf_write[inst->src[i].reg * 16 + inst->src[i].reg_offset + r], 0);
}
}
} else if (inst->src[i].file == HW_REG &&
@@ -941,12 +941,12 @@ fs_instruction_scheduler::calculate_deps()
if (inst->src[i].fixed_hw_reg.vstride == BRW_VERTICAL_STRIDE_0)
size = 1;
for (int r = 0; r < size; r++)
- add_dep(n, last_grf_write[inst->src[i].fixed_hw_reg.nr + r]);
+ add_dep(n, last_grf_write[inst->src[i].fixed_hw_reg.nr + r], 0);
} else {
- add_dep(n, last_fixed_grf_write);
+ add_dep(n, last_fixed_grf_write, 0);
}
} else if (inst->src[i].is_accumulator()) {
- add_dep(n, last_accumulator_write);
+ add_dep(n, last_accumulator_write, 0);
} else if (inst->src[i].file != BAD_FILE &&
inst->src[i].file != IMM &&
inst->src[i].file != UNIFORM &&
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