[Mesa-dev] [PATCH 2/5] radeonsi: set dereferenceable attribute on descriptor arrays
Marek Olšák
maraeo at gmail.com
Wed Jul 13 19:36:19 UTC 2016
On Wed, Jul 13, 2016 at 9:25 PM, Tom Stellard <tom at stellard.net> wrote:
> On Wed, Jul 13, 2016 at 03:20:55PM -0400, Tom Stellard wrote:
>> On Tue, Jul 12, 2016 at 10:52:35PM +0200, Marek Olšák wrote:
>> > From: Marek Olšák <marek.olsak at amd.com>
>> >
>> > This allows moving the loads arbitrarily in the Sinking pass.
>> >
>> > 26002 shaders in 14643 tests
>> > Totals:
>> > SGPRS: 2080160 -> 2080160 (0.00 %)
>> > VGPRS: 798875 -> 797826 (-0.13 %)
>> > Spilled SGPRs: 108485 -> 79165 (-27.03 %)
>> > Spilled VGPRs: 327 -> 327 (0.00 %)
>> > Scratch VGPRs: 1656 -> 1652 (-0.24 %) dwords per thread
>> > Code Size: 36127192 -> 35559780 (-1.57 %) bytes
>> > LDS: 767 -> 767 (0.00 %) blocks
>> > Max Waves: 212464 -> 212672 (0.10 %)
>> > Wait states: 0 -> 0 (0.00 %)
>> >
>> > PERCENTAGES / App Shaders SGPRs VGPRs SpillSGPR SpillVGPR Scratch CodeSize MaxWaves Waits
>> > (unknown) 4 . . . . . . . .
>> > 0ad 6 . . . . . . . .
>> > alien_isolation 2938 . 0.04 % -8.53 % . . -0.71 % -0.06 % .
>> > anholt 10 . . . . . . . .
>> > batman_arkham_origins 589 . -0.58 % -79.54 % . . -6.72 % 0.57 % .
>> > bioshock-infinite 1769 . -0.65 % -89.32 % . . -4.73 % 0.48 % .
>> > borderlands2 3968 . -0.31 % -51.21 % . . -4.09 % 0.22 % .
>> > brutal-legend 338 . -0.03 % -2.95 % . . -0.06 % . .
>> > civilization_beyond.. 116 . . -14.17 % . . -0.88 % . .
>> > counter_strike_glob.. 1142 . . . . . . . .
>> > dirt-showdown 541 . -0.56 % -40.14 % . -3.45 % -1.82 % 0.35 % .
>> > dolphin 22 . . . . . 0.16 % . .
>> > dota2 1747 . . . . . 0.01 % . .
>> > europa_universalis_4 76 . -0.23 % -42.11 % . . -0.96 % . .
>> > f1-2015 774 . -0.09 % -28.89 % . . -2.60 % 0.09 % .
>> > furmark-0.7.0 4 . . . . . . . .
>> > gimark-0.7.0 10 . . . . . . . .
>> > glamor 16 . . . . . . . .
>> > humus-celshading 4 . . . . . . . .
>> > humus-domino 6 . . . . . . . .
>> > humus-dynamicbranching 24 . 0.71 % . . . 0.29 % -0.45 % .
>> > humus-hdr 10 . . . . . . . .
>> > humus-portals 2 . . . . . . . .
>> > humus-volumetricfog.. 6 . . . . . . . .
>> > left_4_dead_2 1762 . . . . . . . .
>> > metro_2033_redux 2670 . -0.10 % -7.15 % . . -0.03 % . .
>> > nexuiz 80 . . . . . . . .
>> > pixmark-julia-fp32 2 . . . . . . . .
>> > pixmark-julia-fp64 2 . . . . . . . .
>> > pixmark-piano-0.7.0 2 . . . . . . . .
>> > pixmark-volplosion-.. 2 . . . . . . . .
>> > plot3d-0.7.0 8 . . . . . . . .
>> > portal 474 . . . . . . . .
>> > sauerbraten 7 . . . . . . . .
>> > serious_sam_3_bfe 392 . . -13.20 % . . -1.81 % . .
>> > supertuxkart 4 . . . . . . . .
>> > talos_principle 324 . -0.21 % -18.39 % . . -2.73 % 0.14 % .
>> > team_fortress_2 808 . . . . . . . .
>> > tesseract 430 . 0.08 % -68.57 % . . -0.45 % . .
>> > tessmark-0.7.0 6 . . . . . . . .
>> > thea 172 . . . . . 0.03 % . .
>> > ue4_effects_cave 299 . -0.04 % -10.15 % . . -0.25 % 0.04 % .
>> > ue4_elemental 586 . -0.02 % -13.93 % . . -0.13 % 0.02 % .
>> > ue4_lightroom_inter.. 74 . -0.17 % -70.00 % . . -1.27 % . .
>> > ue4_realistic_rende.. 92 . . -32.58 % . . -0.35 % . .
>> > unigine_heaven 322 . 0.12 % -54.17 % . . -1.42 % -0.12 % .
>> > unigine_sanctuary 264 . . . . . . . .
>> > unigine_tropics 210 . . . . . . . .
>> > unigine_valley 278 . -0.15 % -40.74 % . . -2.00 % 0.09 % .
>> > unity 72 . . . . . 0.03 % . .
>> > warsow 176 . . . . . . . .
>> > warzone2100 4 . . . . . 0.13 % . .
>> > witcher2 1040 . -0.03 % -86.28 % . . -0.28 % 0.01 % .
>> > xcom_enemy_within 1236 . -0.24 % -63.54 % . . -0.93 % 0.18 % .
>> > yofrankie 82 . -0.61 % -100.00 % . . -0.83 % 0.41 % .
>> > -----------------------------------------------------------------------------------------------------------
>> > Total 26002 . -0.13 % -27.03 % . -0.24 % -1.57 % 0.10 % .
>> > ---
>> > src/gallium/drivers/radeonsi/si_shader.c | 15 +++++++++++----
>> > 1 file changed, 11 insertions(+), 4 deletions(-)
>> >
>> > diff --git a/src/gallium/drivers/radeonsi/si_shader.c b/src/gallium/drivers/radeonsi/si_shader.c
>> > index 31140b1..b23c7c6 100644
>> > --- a/src/gallium/drivers/radeonsi/si_shader.c
>> > +++ b/src/gallium/drivers/radeonsi/si_shader.c
>> > @@ -33,6 +33,7 @@
>> > #include "gallivm/lp_bld_arit.h"
>> > #include "gallivm/lp_bld_bitarit.h"
>> > #include "gallivm/lp_bld_flow.h"
>> > +#include "gallivm/lp_bld_misc.h"
>> > #include "radeon/r600_cs.h"
>> > #include "radeon/radeon_llvm.h"
>> > #include "radeon/radeon_elf_util.h"
>> > @@ -5311,11 +5312,17 @@ static void si_create_function(struct si_shader_context *ctx,
>> > for (i = 0; i <= last_sgpr; ++i) {
>> > LLVMValueRef P = LLVMGetParam(ctx->radeon_bld.main_fn, i);
>> >
>> > - /* We tell llvm that array inputs are passed by value to allow Sinking pass
>> > - * to move load. Inputs are constant so this is fine. */
>> > - if (i <= last_array_pointer)
>> > + /* The combination of:
>> > + * - ByVal
>> > + * - dereferenceable
>> > + * - tbaa
>> > + * allows the optimization passes to move loads and reduces
>> > + * SGPR spilling significantly.
>> > + */
>> > + if (i <= last_array_pointer) {
>> > LLVMAddAttribute(P, LLVMByValAttribute);
>> > - else
>> > + lp_add_attr_dereferenceable(P, UINT64_MAX);
>>
>> I'm not sure if anything bad will happen passing UINT64_MAX here, but
>> is there any way we can get the buffer size here, so we can
>> pass a more accurate value?
>>
>
> Actually, these are all array pointers, so we should be able to get the
> size pretty easily.
Matt on IRC suggested -1 (the unsigned maximum). I don't know if
indirect indexing will fail the isDereferenceable test with the real
size. Is there a reason to use the real size other than "so it doesn't
look silly in the printed IR"? In my opinion, we should set
dereferenceable(UINT64_MAX) on all pointers, because the GPU doesn't
terminate the program on bad pointer dereference like CPUs do.
Marek
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