[Mesa-dev] [PATCH 6/6] i965/fs: Propagate conditional modifiers from not instructions
Iago Toral
itoral at igalia.com
Fri Jun 15 10:09:07 UTC 2018
On Thu, 2018-06-14 at 17:43 -0700, Ian Romanick wrote:
> From: Ian Romanick <ian.d.romanick at intel.com>
>
> Skylake
> total instructions in shared programs: 14399081 -> 14399010 (<.01%)
> instructions in affected programs: 26961 -> 26890 (-0.26%)
> helped: 57
> HURT: 0
> helped stats (abs) min: 1 max: 6 x̄: 1.25 x̃: 1
> helped stats (rel) min: 0.16% max: 0.80% x̄: 0.30% x̃: 0.18%
> 95% mean confidence interval for instructions value: -1.50 -0.99
> 95% mean confidence interval for instructions %-change: -0.35% -0.25%
> Instructions are helped.
>
> total cycles in shared programs: 532978307 -> 532976050 (<.01%)
> cycles in affected programs: 468629 -> 466372 (-0.48%)
> helped: 33
> HURT: 20
> helped stats (abs) min: 3 max: 360 x̄: 116.52 x̃: 98
> helped stats (rel) min: 0.06% max: 3.63% x̄: 1.66% x̃: 1.27%
> HURT stats (abs) min: 2 max: 172 x̄: 79.40 x̃: 43
> HURT stats (rel) min: 0.04% max: 3.02% x̄: 1.48% x̃: 0.44%
> 95% mean confidence interval for cycles value: -81.29 -3.88
> 95% mean confidence interval for cycles %-change: -1.07% 0.12%
> Inconclusive result (%-change mean confidence interval includes 0).
>
> All Gen6+ platforms, except Ivy Bridge, had similar results. (Haswell
> shown)
> total instructions in shared programs: 12973897 -> 12973838 (<.01%)
> instructions in affected programs: 25970 -> 25911 (-0.23%)
> helped: 55
> HURT: 0
> helped stats (abs) min: 1 max: 2 x̄: 1.07 x̃: 1
> helped stats (rel) min: 0.16% max: 0.62% x̄: 0.28% x̃: 0.18%
> 95% mean confidence interval for instructions value: -1.14 -1.00
> 95% mean confidence interval for instructions %-change: -0.32% -0.24%
> Instructions are helped.
>
> total cycles in shared programs: 410355841 -> 410352067 (<.01%)
> cycles in affected programs: 578454 -> 574680 (-0.65%)
> helped: 47
> HURT: 5
> helped stats (abs) min: 3 max: 360 x̄: 85.74 x̃: 18
> helped stats (rel) min: 0.05% max: 3.68% x̄: 1.18% x̃: 0.38%
> HURT stats (abs) min: 2 max: 242 x̄: 51.20 x̃: 4
> HURT stats (rel) min: <.01% max: 0.45% x̄: 0.15% x̃: 0.11%
> 95% mean confidence interval for cycles value: -104.89 -40.27
> 95% mean confidence interval for cycles %-change: -1.45% -0.66%
> Cycles are helped.
>
> Ivy Bridge
> total instructions in shared programs: 11679351 -> 11679301 (<.01%)
> instructions in affected programs: 28208 -> 28158 (-0.18%)
> helped: 50
> HURT: 0
> helped stats (abs) min: 1 max: 1 x̄: 1.00 x̃: 1
> helped stats (rel) min: 0.12% max: 0.54% x̄: 0.23% x̃: 0.16%
> 95% mean confidence interval for instructions value: -1.00 -1.00
> 95% mean confidence interval for instructions %-change: -0.27% -0.19%
> Instructions are helped.
>
> total cycles in shared programs: 257445362 -> 257444662 (<.01%)
> cycles in affected programs: 419338 -> 418638 (-0.17%)
> helped: 40
> HURT: 3
> helped stats (abs) min: 1 max: 170 x̄: 65.05 x̃: 24
> helped stats (rel) min: 0.02% max: 3.51% x̄: 1.26% x̃: 0.41%
> HURT stats (abs) min: 2 max: 1588 x̄: 634.00 x̃: 312
> HURT stats (rel) min: 0.05% max: 2.97% x̄: 1.21% x̃: 0.62%
> 95% mean confidence interval for cycles value: -97.96 65.41
> 95% mean confidence interval for cycles %-change: -1.56% -0.62%
> Inconclusive result (value mean confidence interval includes 0).
>
> No changes on Iron Lake or GM45.
>
> Signed-off-by: Ian Romanick <ian.d.romanick at intel.com>
> ---
> src/intel/compiler/brw_fs_cmod_propagation.cpp | 63
> +++++++++++++++++++++++++-
> 1 file changed, 62 insertions(+), 1 deletion(-)
>
> diff --git a/src/intel/compiler/brw_fs_cmod_propagation.cpp
> b/src/intel/compiler/brw_fs_cmod_propagation.cpp
> index b4f05613e98..c935cc66c81 100644
> --- a/src/intel/compiler/brw_fs_cmod_propagation.cpp
> +++ b/src/intel/compiler/brw_fs_cmod_propagation.cpp
> @@ -111,6 +111,61 @@ cmod_propagate_cmp_to_add(const gen_device_info
> *devinfo, bblock_t *block,
> return false;
> }
>
> +/**
> + * Propagate conditional modifiers from NOT instructions
> + *
> + * Attempt to convert sequences like
> + *
> + * or(8) g78<8,8,1> g76<8,8,1>UD g77<8,8,1>UD
> + * ...
> + * not.nz.f0(8) null g78<8,8,1>UD
> + *
> + * into
> + *
> + * or.z.f0(8) g78<8,8,1> g76<8,8,1>UD g77<8,8,1>UD
> + */
> +static bool
> +cmod_propagate_not(const gen_device_info *devinfo, bblock_t *block,
> + fs_inst *inst)
> +{
> + const enum brw_conditional_mod cond = brw_negate_cmod(inst-
> >conditional_mod);
> + bool read_flag = false;
> +
> + foreach_inst_in_block_reverse_starting_from(fs_inst, scan_inst,
> inst) {
> + if (regions_overlap(scan_inst->dst, scan_inst->size_written,
> + inst->src[0], inst->size_read(0))) {
> + if (cond != BRW_CONDITIONAL_Z &&
> + cond != BRW_CONDITIONAL_NZ)
> + break;
Looks like we can do this before the loop.
> +
> + if (scan_inst->opcode != BRW_OPCODE_OR &&
> + scan_inst->opcode != BRW_OPCODE_AND)
> + break;
> +
> + if (scan_inst->is_partial_write() ||
> + scan_inst->dst.offset != inst->src[0].offset ||
> + scan_inst->exec_size != inst->exec_size)
> + break;
> +
> + if (scan_inst->can_do_cmod() &&
> + ((!read_flag && scan_inst->conditional_mod ==
> BRW_CONDITIONAL_NONE) ||
> + scan_inst->conditional_mod == cond)) {
> + scan_inst->conditional_mod = cond;
> + inst->remove(block);
> + return true;
> + }
> + break;
> + }
> +
> + if (scan_inst->flags_written())
> + break;
> +
> + read_flag = read_flag || scan_inst->flags_read(devinfo);
> + }
> +
> + return false;
> +}
> +
> static bool
> opt_cmod_propagation_local(const gen_device_info *devinfo, bblock_t
> *block)
> {
> @@ -122,7 +177,8 @@ opt_cmod_propagation_local(const gen_device_info
> *devinfo, bblock_t *block)
>
> if ((inst->opcode != BRW_OPCODE_AND &&
> inst->opcode != BRW_OPCODE_CMP &&
> - inst->opcode != BRW_OPCODE_MOV) ||
> + inst->opcode != BRW_OPCODE_MOV &&
> + inst->opcode != BRW_OPCODE_NOT) ||
> inst->predicate != BRW_PREDICATE_NONE ||
> !inst->dst.is_null() ||
> (inst->src[0].file != VGRF && inst->src[0].file != ATTR &&
> @@ -162,6 +218,11 @@ opt_cmod_propagation_local(const gen_device_info
> *devinfo, bblock_t *block)
> continue;
> }
>
> + if (inst->opcode == BRW_OPCODE_NOT) {
> + progress = cmod_propagate_not(devinfo, block, inst) ||
> progress;
> + continue;
> + }
> +
> bool read_flag = false;
> foreach_inst_in_block_reverse_starting_from(fs_inst,
> scan_inst, inst) {
> if (regions_overlap(scan_inst->dst, scan_inst-
> >size_written,
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