[Mesa-dev] [PATCH] i965/fs: Use conditional sends to do FB writes on HSW+.
Eric Anholt
eric at anholt.net
Fri Feb 14 17:31:15 PST 2014
This drops the MOVs for header setup, which are totally mis-scheduled.
total instructions in shared programs: 1590047 -> 1589331 (-0.05%)
instructions in affected programs: 43729 -> 43013 (-1.64%)
GAINED: 0
LOST: 0
glb27-trex:
x before
+ after
+-----------------------------------------------------------------------------+
| + x xx + + + |
| ++ + xxx ++x xx + ** *x+ + + + x * |
|+x xx x* x+++xx*x*xx+++*+*xx++** *x* x+***x*+xx+* + * + + *|
| |__|__________MA___A___________|___| |
+-----------------------------------------------------------------------------+
N Min Max Median Avg Stddev
x 49 62.33 65.41 63.49 63.53449 0.62757822
+ 50 62.28 65.4 63.7 63.6982 0.656564
No difference proven at 95.0% confidence
---
src/mesa/drivers/dri/i965/brw_eu_emit.c | 2 --
src/mesa/drivers/dri/i965/brw_fs_generator.cpp | 22 ++++++++++++---------
src/mesa/drivers/dri/i965/brw_fs_visitor.cpp | 14 ++++++++++++-
src/mesa/drivers/dri/i965/gen8_fs_generator.cpp | 26 +++++++++++++++++++------
4 files changed, 46 insertions(+), 18 deletions(-)
diff --git a/src/mesa/drivers/dri/i965/brw_eu_emit.c b/src/mesa/drivers/dri/i965/brw_eu_emit.c
index 8ab043f..5360b56 100644
--- a/src/mesa/drivers/dri/i965/brw_eu_emit.c
+++ b/src/mesa/drivers/dri/i965/brw_eu_emit.c
@@ -2241,8 +2241,6 @@ void brw_fb_WRITE(struct brw_compile *p,
} else {
insn = next_insn(p, BRW_OPCODE_SEND);
}
- /* The execution mask is ignored for render target writes. */
- insn->header.predicate_control = 0;
insn->header.compression_control = BRW_COMPRESSION_NONE;
if (brw->gen >= 6) {
diff --git a/src/mesa/drivers/dri/i965/brw_fs_generator.cpp b/src/mesa/drivers/dri/i965/brw_fs_generator.cpp
index 00f19dc..ee13ced 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_generator.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_generator.cpp
@@ -114,18 +114,22 @@ fs_generator::generate_fb_write(fs_inst *inst)
brw_set_mask_control(p, BRW_MASK_DISABLE);
brw_set_compression_control(p, BRW_COMPRESSION_NONE);
- if ((fp && fp->UsesKill) || c->key.alpha_test_func) {
- struct brw_reg pixel_mask;
+ if (inst->header_present) {
+ /* On HSW, the GPU will use the predicate on SENDC, unless the header is
+ * present.
+ */
+ if (!brw->is_haswell && ((fp && fp->UsesKill) ||
+ c->key.alpha_test_func)) {
+ struct brw_reg pixel_mask;
- if (brw->gen >= 6)
- pixel_mask = retype(brw_vec1_grf(1, 7), BRW_REGISTER_TYPE_UW);
- else
- pixel_mask = retype(brw_vec1_grf(0, 0), BRW_REGISTER_TYPE_UW);
+ if (brw->gen >= 6)
+ pixel_mask = retype(brw_vec1_grf(1, 7), BRW_REGISTER_TYPE_UW);
+ else
+ pixel_mask = retype(brw_vec1_grf(0, 0), BRW_REGISTER_TYPE_UW);
- brw_MOV(p, pixel_mask, brw_flag_reg(0, 1));
- }
+ brw_MOV(p, pixel_mask, brw_flag_reg(0, 1));
+ }
- if (inst->header_present) {
if (brw->gen >= 6) {
brw_set_compression_control(p, BRW_COMPRESSION_COMPRESSED);
brw_MOV(p,
diff --git a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
index 45b053d..70b7c66 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_visitor.cpp
@@ -2743,7 +2743,7 @@ fs_visitor::emit_fb_writes()
* thread message and on all dual-source messages."
*/
if (brw->gen >= 6 &&
- !this->fp->UsesKill &&
+ (brw->is_haswell || brw->gen >= 8 || !this->fp->UsesKill) &&
!do_dual_src &&
c->key.nr_color_regions == 1) {
header_present = false;
@@ -2840,6 +2840,10 @@ fs_visitor::emit_fb_writes()
inst->mlen = nr - base_mrf;
inst->eot = true;
inst->header_present = header_present;
+ if ((brw->gen >= 8 || brw->is_haswell) && fp->UsesKill) {
+ inst->predicate = BRW_PREDICATE_NORMAL;
+ inst->flag_subreg = 1;
+ }
c->prog_data.dual_src_blend = true;
this->current_annotation = NULL;
@@ -2885,6 +2889,10 @@ fs_visitor::emit_fb_writes()
inst->mlen = nr - base_mrf;
inst->eot = eot;
inst->header_present = header_present;
+ if ((brw->gen >= 8 || brw->is_haswell) && fp->UsesKill) {
+ inst->predicate = BRW_PREDICATE_NORMAL;
+ inst->flag_subreg = 1;
+ }
}
if (c->key.nr_color_regions == 0) {
@@ -2902,6 +2910,10 @@ fs_visitor::emit_fb_writes()
inst->mlen = nr - base_mrf;
inst->eot = true;
inst->header_present = header_present;
+ if ((brw->gen >= 8 || brw->is_haswell) && fp->UsesKill) {
+ inst->predicate = BRW_PREDICATE_NORMAL;
+ inst->flag_subreg = 1;
+ }
}
this->current_annotation = NULL;
diff --git a/src/mesa/drivers/dri/i965/gen8_fs_generator.cpp b/src/mesa/drivers/dri/i965/gen8_fs_generator.cpp
index 332b14f..ea16320 100644
--- a/src/mesa/drivers/dri/i965/gen8_fs_generator.cpp
+++ b/src/mesa/drivers/dri/i965/gen8_fs_generator.cpp
@@ -61,14 +61,21 @@ gen8_fs_generator::mark_surface_used(unsigned surf_index)
void
gen8_fs_generator::generate_fb_write(fs_inst *ir)
{
- if (fp && fp->UsesKill) {
- gen8_instruction *mov =
- MOV(retype(brw_vec1_grf(1, 7), BRW_REGISTER_TYPE_UW),
- brw_flag_reg(0, 1));
- gen8_set_mask_control(mov, BRW_MASK_DISABLE);
- }
+ /* Disable the discard condition while setting up the header. */
+ default_state.predicate = BRW_PREDICATE_NONE;
+ default_state.predicate_inverse = false;
+ default_state.flag_subreg_nr = 0;
if (ir->header_present) {
+ /* The GPU will use the predicate on SENDC, unless the header is present.
+ */
+ if (fp && fp->UsesKill) {
+ gen8_instruction *mov =
+ MOV(retype(brw_vec1_grf(1, 7), BRW_REGISTER_TYPE_UW),
+ brw_flag_reg(0, 1));
+ gen8_set_mask_control(mov, BRW_MASK_DISABLE);
+ }
+
gen8_instruction *mov =
MOV_RAW(brw_message_reg(ir->base_mrf), brw_vec8_grf(0, 0));
gen8_set_exec_size(mov, BRW_EXECUTE_16);
@@ -88,6 +95,13 @@ gen8_fs_generator::generate_fb_write(fs_inst *ir)
}
}
+ /* Set the predicate back to get the conditional write if necessary for
+ * discards.
+ */
+ default_state.predicate = ir->predicate;
+ default_state.predicate_inverse = ir->predicate_inverse;
+ default_state.flag_subreg_nr = ir->flag_subreg;
+
gen8_instruction *inst = next_inst(BRW_OPCODE_SENDC);
gen8_set_dst(brw, inst, retype(vec8(brw_null_reg()), BRW_REGISTER_TYPE_UW));
gen8_set_src0(brw, inst, brw_message_reg(ir->base_mrf));
--
1.9.rc1
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