GLSL/TGSI On-Disk Shader Cache Lands In Mesa For R600g/RadeonSI

[phoronix]

Phoronix: GLSL/TGSI On-Disk Shader Cache Lands In Mesa For R600g/RadeonSI

Timothy Arceri who has been working on the Mesa on-disk shader cache for months and most recently began working for Valve on the AMD Linux driver stack has landed support in Mesa 17.1-devel for the GLSL/TGSI on-disk shader cache for the R600g and RadeonSI Gallium3D drivers...

http://www.phoronix.com/scan.php?page=news_item&px=GLSL-TGSI-Shader-Cache-Lands

[Herem]

As the shader cache will mainly affect the smoothness of games rather than the FPS averages, I'm not sure the normal benchmarks will demonstrate much of a change other than a very slight increase in the average FPS.

Ideally if it is possible it would be good to see a graph of individual frame times to show how the patch affects the smoothness of the run by hopefully eliminating small stutters in the frame delivery times.

[GruenSein]

Is this the version which stores the intermediate bytecode or the one storing compiled binaries?

[tarceri]

As the shader cache will mainly affect the smoothness of games rather than the FPS averages, I'm not sure the normal benchmarks will demonstrate much of a change other than a very slight increase in the average FPS.

The thing to look at would the min fps which I believe PTS can report for some tests. It would be interesting to see the results on the ue4 elemental demo, this demo is probably the worse case of compiling shaders on the fly that I have seen.

[Michael]

The thing to look at would the min fps which I believe PTS can report for some tests. It would be interesting to see the results on the ue4 elemental demo, this demo is probably the worse case of compiling shaders on the fly that I have seen.

Yep, minimum time is shown when exposed by the engine/game. Okay, will look at elemental.

[ElderSnake]

This is great news! I'll try it out tonight. Should at least greatly reduce Deus Ex loading times.

[Hibbelharry]

This is a good day. Thanks Timothy!

[Herem]

The thing to look at would the min fps which I believe PTS can report for some tests. It would be interesting to see the results on the ue4 elemental demo, this demo is probably the worse case of compiling shaders on the fly that I have seen.

There are 2 issues that immediately spring to mind with just looking at the minimum FPS. The minimum FPS may not be caused by compiling shaders (so it may not change at all) and also the minimum doesn't give any indication of the frequency of stutters in performance.

There have been other sites investigating frame pacing issues in the past such as Scott Wasson at the TechReport. He wrote a number of articles around the issue of micro stutters and how minimising these was critical to a good game play experience. This investigation ultimately lead AMD to release new versions of their propriety drivers for Windows with frame pacing code added to reduce the stutters http://techreport.com/review/25167/f...radeon-hd-7990 This also eventually lead to Scott Wasson leaving the site he founded and joining the AMD Radeon Technologies Group.

[FireBurn]

Can someone upload the elemental demo somewhere please? The official http://ue4linux.raxxy.com/elemental_demo.tar.bz2 no longer works

[smitty3268]

Is this the version which stores the intermediate bytecode or the one storing compiled binaries?

It's only storing the TGSI bytecode for now, so the machine code still needs to be compiled after grabbing the cached shader data.

I doubt it will make a huge change for radeonsi, but it might be pretty decent for r600.