[Mesa-dev] [PATCH 08/11] i965/fs: Generate better code for fsign multiplied by a value
Ian Romanick
idr at freedesktop.org
Mon Sep 10 23:29:11 UTC 2018
From: Ian Romanick <ian.d.romanick at intel.com>
shader-db results:
Broadwell and Skylake had similar results. (Skylake shown)
total instructions in shared programs: 15105981 -> 15090997 (-0.10%)
instructions in affected programs: 977852 -> 962868 (-1.53%)
helped: 4531
HURT: 0
helped stats (abs) min: 1 max: 221 x̄: 3.31 x̃: 2
helped stats (rel) min: 0.07% max: 10.00% x̄: 1.83% x̃: 1.33%
95% mean confidence interval for instructions value: -3.49 -3.13
95% mean confidence interval for instructions %-change: -1.86% -1.79%
Instructions are helped.
total cycles in shared programs: 566053975 -> 565827580 (-0.04%)
cycles in affected programs: 14922172 -> 14695777 (-1.52%)
helped: 4373
HURT: 125
helped stats (abs) min: 1 max: 6190 x̄: 54.16 x̃: 28
helped stats (rel) min: 0.01% max: 29.14% x̄: 2.74% x̃: 2.31%
HURT stats (abs) min: 1 max: 1836 x̄: 83.53 x̃: 44
HURT stats (rel) min: 0.01% max: 34.36% x̄: 2.85% x̃: 1.64%
95% mean confidence interval for cycles value: -55.94 -44.73
95% mean confidence interval for cycles %-change: -2.64% -2.52%
Cycles are helped.
total spills in shared programs: 11085 -> 11084 (<.01%)
spills in affected programs: 49 -> 48 (-2.04%)
helped: 1
HURT: 0
total fills in shared programs: 23143 -> 23142 (<.01%)
fills in affected programs: 92 -> 91 (-1.09%)
helped: 1
HURT: 0
Haswell
total instructions in shared programs: 13682846 -> 13671160 (-0.09%)
instructions in affected programs: 726095 -> 714409 (-1.61%)
helped: 3478
HURT: 0
helped stats (abs) min: 1 max: 221 x̄: 3.36 x̃: 2
helped stats (rel) min: 0.07% max: 10.64% x̄: 1.94% x̃: 1.47%
95% mean confidence interval for instructions value: -3.58 -3.14
95% mean confidence interval for instructions %-change: -1.99% -1.89%
Instructions are helped.
total cycles in shared programs: 449604795 -> 449445686 (-0.04%)
cycles in affected programs: 11722803 -> 11563694 (-1.36%)
helped: 3310
HURT: 138
helped stats (abs) min: 1 max: 1780 x̄: 49.75 x̃: 18
helped stats (rel) min: <.01% max: 29.13% x̄: 2.21% x̃: 1.72%
HURT stats (abs) min: 1 max: 258 x̄: 40.31 x̃: 18
HURT stats (rel) min: <.01% max: 15.30% x̄: 1.79% x̃: 0.79%
95% mean confidence interval for cycles value: -50.65 -41.64
95% mean confidence interval for cycles %-change: -2.12% -1.98%
Cycles are helped.
LOST: 1
GAINED: 0
Ivy Bridge
total instructions in shared programs: 12030700 -> 12023562 (-0.06%)
instructions in affected programs: 638233 -> 631095 (-1.12%)
helped: 2498
HURT: 0
helped stats (abs) min: 1 max: 39 x̄: 2.86 x̃: 2
helped stats (rel) min: 0.05% max: 10.00% x̄: 1.28% x̃: 1.02%
95% mean confidence interval for instructions value: -2.96 -2.75
95% mean confidence interval for instructions %-change: -1.32% -1.24%
Instructions are helped.
total cycles in shared programs: 256243891 -> 256115699 (-0.05%)
cycles in affected programs: 11801287 -> 11673095 (-1.09%)
helped: 2433
HURT: 53
helped stats (abs) min: 1 max: 1348 x̄: 56.44 x̃: 26
helped stats (rel) min: 0.01% max: 24.56% x̄: 1.90% x̃: 1.53%
HURT stats (abs) min: 1 max: 5364 x̄: 172.36 x̃: 39
HURT stats (rel) min: 0.03% max: 51.96% x̄: 3.57% x̃: 1.18%
95% mean confidence interval for cycles value: -58.76 -44.38
95% mean confidence interval for cycles %-change: -1.86% -1.70%
Cycles are helped.
Sandy Bridge
total instructions in shared programs: 10831556 -> 10831527 (<.01%)
instructions in affected programs: 3777 -> 3748 (-0.77%)
helped: 17
HURT: 0
helped stats (abs) min: 1 max: 4 x̄: 1.71 x̃: 1
helped stats (rel) min: 0.13% max: 9.52% x̄: 3.58% x̃: 2.73%
95% mean confidence interval for instructions value: -2.27 -1.14
95% mean confidence interval for instructions %-change: -5.14% -2.03%
Instructions are helped.
total cycles in shared programs: 154504015 -> 154503922 (<.01%)
cycles in affected programs: 47336 -> 47243 (-0.20%)
helped: 15
HURT: 8
helped stats (abs) min: 1 max: 81 x̄: 16.13 x̃: 4
helped stats (rel) min: 0.01% max: 10.59% x̄: 1.54% x̃: 0.73%
HURT stats (abs) min: 14 max: 33 x̄: 18.62 x̃: 17
HURT stats (rel) min: 0.33% max: 2.78% x̄: 2.42% x̃: 2.71%
95% mean confidence interval for cycles value: -15.10 7.01
95% mean confidence interval for cycles %-change: -1.41% 1.08%
Inconclusive result (value mean confidence interval includes 0).
Iron Lake
total instructions in shared programs: 8207937 -> 8207823 (<.01%)
instructions in affected programs: 9392 -> 9278 (-1.21%)
helped: 48
HURT: 0
helped stats (abs) min: 1 max: 11 x̄: 2.38 x̃: 2
helped stats (rel) min: 0.15% max: 7.02% x̄: 2.02% x̃: 1.46%
95% mean confidence interval for instructions value: -3.05 -1.70
95% mean confidence interval for instructions %-change: -2.47% -1.57%
Instructions are helped.
total cycles in shared programs: 187478820 -> 187478330 (<.01%)
cycles in affected programs: 260626 -> 260136 (-0.19%)
helped: 34
HURT: 11
helped stats (abs) min: 2 max: 134 x̄: 15.41 x̃: 7
helped stats (rel) min: 0.03% max: 5.62% x̄: 0.75% x̃: 0.14%
HURT stats (abs) min: 2 max: 8 x̄: 3.09 x̃: 2
HURT stats (rel) min: 0.12% max: 0.86% x̄: 0.32% x̃: 0.28%
95% mean confidence interval for cycles value: -18.75 -3.03
95% mean confidence interval for cycles %-change: -0.86% -0.11%
Cycles are helped.
GM45
total instructions in shared programs: 5047448 -> 5047391 (<.01%)
instructions in affected programs: 4783 -> 4726 (-1.19%)
helped: 24
HURT: 0
helped stats (abs) min: 1 max: 11 x̄: 2.38 x̃: 2
helped stats (rel) min: 0.15% max: 6.78% x̄: 1.95% x̃: 1.41%
95% mean confidence interval for instructions value: -3.36 -1.39
95% mean confidence interval for instructions %-change: -2.58% -1.31%
Instructions are helped.
total cycles in shared programs: 128068274 -> 128068004 (<.01%)
cycles in affected programs: 152576 -> 152306 (-0.18%)
helped: 16
HURT: 7
helped stats (abs) min: 2 max: 134 x̄: 18.50 x̃: 10
helped stats (rel) min: 0.03% max: 5.62% x̄: 0.85% x̃: 0.16%
HURT stats (abs) min: 2 max: 8 x̄: 3.71 x̃: 4
HURT stats (rel) min: 0.12% max: 0.86% x̄: 0.34% x̃: 0.28%
95% mean confidence interval for cycles value: -23.99 0.51
95% mean confidence interval for cycles %-change: -1.09% 0.12%
Inconclusive result (value mean confidence interval includes 0).
Signed-off-by: Ian Romanick <ian.d.romanick at intel.com>
---
src/intel/compiler/brw_fs_nir.cpp | 45 +++++++++++++++++++++++++++++++++++++++
1 file changed, 45 insertions(+)
diff --git a/src/intel/compiler/brw_fs_nir.cpp b/src/intel/compiler/brw_fs_nir.cpp
index ef4c41da132..191cb9afde8 100644
--- a/src/intel/compiler/brw_fs_nir.cpp
+++ b/src/intel/compiler/brw_fs_nir.cpp
@@ -25,6 +25,7 @@
#include "brw_fs.h"
#include "brw_fs_surface_builder.h"
#include "brw_nir.h"
+#include "nir_search_helpers.h"
#include "util/u_math.h"
using namespace brw;
@@ -801,6 +802,41 @@ fs_visitor::emit_fsign(const fs_builder &bld, const nir_alu_instr *instr,
}
}
+/**
+ * Deteremine whether sources of a nir_op_fmul can be fused with a nir_op_fsign
+ *
+ * Checks the operands of a \c nir_op_fmul to determine whether or not
+ * \c emit_fsign could fuse the multiplication with the \c sign() calculation.
+ *
+ * \param instr The multiplication instruction
+ *
+ * \param fsign_src The source of \c instr that may or may not be a
+ * \c nir_op_fsign
+ */
+static bool
+can_fuse_fmul_fsign(nir_alu_instr *instr, unsigned fsign_src)
+{
+ assert(instr->op == nir_op_fmul);
+
+ nir_alu_instr *const fsign_instr =
+ nir_src_as_alu_instr(&instr->src[fsign_src].src);
+
+ /* Rules:
+ *
+ * 1. instr->src[fsign_src] must be a nir_op_fsign.
+ * 2. The nir_op_fsign can only be used by this multiplication.
+ * 3. The source that is the nir_op_fsign does not have source modifiers.
+ * \c emit_fsign only examines the source modifiers of the source of the
+ * \c nir_op_fsign.
+ *
+ * The nir_op_fsign must also not have the saturate modifier, but steps
+ * have already been taken (in nir_opt_algebraic) to ensure that.
+ */
+ return fsign_instr != NULL && fsign_instr->op == nir_op_fsign &&
+ is_used_once(fsign_instr) &&
+ !instr->src[fsign_src].abs && !instr->src[fsign_src].negate;
+}
+
void
fs_visitor::nir_emit_alu(const fs_builder &bld, nir_alu_instr *instr)
{
@@ -809,6 +845,15 @@ fs_visitor::nir_emit_alu(const fs_builder &bld, nir_alu_instr *instr)
return;
}
+ if (instr->op == nir_op_fmul) {
+ for (unsigned i = 0; i < 2; i++) {
+ if (can_fuse_fmul_fsign(instr, i)) {
+ emit_fsign(bld, instr, i);
+ return;
+ }
+ }
+ }
+
struct brw_wm_prog_key *fs_key = (struct brw_wm_prog_key *) this->key;
fs_inst *inst;
--
2.14.4
More information about the mesa-dev
mailing list