[Bf-cycles] CUDA performance tests

[Brecht Van Lommel]

Hi David,

Thanks for the tests. I think it's probably the same issue as this bug
report, so you can put your findings there:
https://developer.blender.org/T40027

I'm not sure where the increased memory usage would come from, I can't
see any commit in that date range that would explain that.

Brecht.

On Sat, May 17, 2014 at 7:08 PM, David Black <db4tech at yahoo.co.uk> wrote:
> Hi Brecht,
>
> Spent the afternoon carrying out performance tests on a heavy scene (lots of
> displacement and hair), sorry scene is test work for a company so unable to
> share.
>
> GPGPU tests performed with an 2GB GTX 580m
>
> Small border region render of whole scene (F12 final render)
> Blender 2.70a
> Time:02:13 Mem:1540
>
> Blender 2.70.4 (and .5)
> Time:10:53 Mem:1743
>
> In case there are several accumulating factors involved (other than
> __launch_bounds__ ), after testing many Blender versions managed to narrow
> down dates, big slowdown and increased memory usage was introduced between
> 17th and 27th April.
>
> Also, post slowdown, render preview does not begin until the 12th sample,
> thought the render and/or Blender had frozen? Synchronizing objects and BVH
> build time is also slightly slower.
>
> Would you like me to open a bug report?
>
> Hope above information is in some way helpful.
>
> David
>
> 3d-designs-davidblack.blogspot.com
>
> On 25/04/2014 16:44, Brecht Van Lommel wrote:
>
> Hi all,
>
> We're having some trouble with CUDA performance at the moment, with in
> a performance regression on Titan cards compared to 2.69, and unclear
> effects from recent changes. Further there's the new CUDA 6.0 toolkit,
> which we ideally could move to, as sticking to 5.0 is a problem with
> newer compilers.
>
> We could use some help testing all this, especially for Titan cards as
> I don't have one of those.
>
>
> There's a google doc here:
> https://docs.google.com/spreadsheets/d/1IKvO6s7h_0oVGbGE3giowx2fBvyXzIfdM3qCSfROJfI
>
> For now I'm assuming someone with a Titan card can make own builds to
> test these git revisions. If not we can build and upload binaries to
> test.
>
> The test is:
> * download: http://www.pasteall.org/blend/28679
> * run: ./blender -b modified_bmw.blend -f 1
>
> If you've got a different .blend file that is giving performance
> regressions, or you find different behavior when rendering in the UI
> rather than command line, then results from that are welcome too.
>
>
> The information that I'm looking for from this is especially:
> * Which revision caused the Titan performance regressions?
> * Is CUDA 6.0 performance acceptable to us for the next release?
> * Were there significant performance regressions due to recent changes?
> * Which effect do the two provided patches have when building with CUDA 6.0?
>
> Thanks,
> Brecht.
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