[Mesa-dev] r600 sb test results

[Vadim Girlin]

On 05/01/2013 11:36 PM, Lauri Kasanen wrote:
> Hi Vadim
>
> Now that it built, I could test your optimizations in my own apps.
> These are on current master 8eef6ad, on a RV710 (HD 4350 pci-e).
>
> In one of my private apps, using R600_DEBUG=sb caused regressions: FPS
> went from 28 to 7, the SSAO shader gave visual distortions/flicker, and
> the cpu was constantly pegged.
>
> Here's the output from R600_DEBUG=sb,sbstat in case it helps:
> http://bayfiles.net/file/Pmkh/PUj0Ru/vadim.gz
>
> It seems as if it's constantly handling new shaders? My app certainly
> issues no new shaders, they are all linked when the app starts.

Hi,

r600g may rebuild shaders at runtime because some GL features are 
implemented in shader code, so if your app changes some specific GL 
states (e.g. two-sided rendering mode), then r600g has to build and 
switch between different shader variants.

On the other hand there is caching of shader variants in r600g 
implemented specially to prevent repetitive rebuilding of shaders, looks 
like it doesn't work in your case for some reason. Optimizations take 
more time than rebuilding with default backend, that explains 
performance regression.

Could you provide some test app that reproduces these issues?

Please also send me the dump with "R600_DEBUG=sb,ps,vs", maybe I'll be 
able to spot anything wrong there.

>
> Let me know what you need to debug this.
>
> - Lauri
>
> PS: I'm not sure if this should be public or not, I think you're the
> only one working on it?

Yes, I doubt that anyone else will work on it, on the other hand I think 
reporting this on the list might help other users who will possibly hit 
similar issues. Also at least in this case it looks rather like a 
problem in r600g, so I'm cc'ing mesa-dev, r600-sb just made this issue 
more noticeable because shader rebuilding with optimization requires 
more time.

Vadim