[Bf-committers] Cycles CUDA Toolkit 8 transition

[Sergey Sharybin]

Interesting.

Can you test revision 6353ecb and the one prior to it to see if it's this
revision caused the problem?

On Wed, Aug 3, 2016 at 12:27 AM, PerfectionCat <sindra1961reborn at yahoo.co.jp
> wrote:

> Hi.
>
> blender which built using a source file at the time of 467e12514e60 in
> CUDA8 has a shorter time required for rendering of BMW for around 20
> seconds.
>
> SHA-1-2f5db2e45b7a8af51b15c45bb41f5dcb49ae9d4d is slow.
> SHA-1-467e12514e60b4130cd0a33b59f53aa4cf7056b6 is fast.
>
> Windows 10 pro 64bits
>
> Intel i7 6700K 4.4GHz
> NVIDIA GTX 1070
> MEMORY 16GB
>
>
> With best regards, PerfectionCat.
>
>
>
> ----- Original Message -----
> >From: Sergey Sharybin <sergey.vfx at gmail.com>
> >To: Blender Developers <bf-committers at blender.org>
> >Date: 2016/8/2, Tue 23:44
> >Subject: Re: [Bf-committers] Cycles CUDA Toolkit 8 transition
> >
> >Hey again,
> >
> >Spent majority of the day trying to solve the regression, without much
> >success. Even simplest kernel needed for BMW scene is about 10% slower.
> >This is mainly coming from bump nodes. Enabling all other features makes
> >things even worse performance wise.
> >
> >I did some tweaks again to make sure all functions are inlined in the same
> >manner by CUDA 8.0 as they used to be before. So now PTax output shows
> >exactly same function, but for some reason spills are just higher with new
> >toolkit and at the same time stack usage is reasonably slower. Not sure
> yet
> >what's going on here and think we'd better leave this alone for until
> >official toolkit is released.
> >
> >For the time being i've switched buildbots to use more complicated setup,
> >using CUDA 7.5 for all kernels except sm_60 and sm_61 (new generation
> >cards) and using new toolkit only for new kernels.
> >
> >So hopefully now all maxwell and lower crads have same performance as
> >before. And yet users of new cards can have some degree of GPU rendering.
> >
> >
> >On Mon, Aug 1, 2016 at 6:15 PM, Sergey Sharybin <sergey.vfx at gmail.com>
> >wrote:
> >
> >> Hey everyone,
> >>
> >> In order to make Cycles officially support new Pascal cards (GTX 10x0)
> it
> >> is crucial to use CUDA Toolkit 8. While it is still in the RC stage we
> >> started looking into making it official one for Cycles.
> >>
> >> There is already some initial work done:
> >>
> >> - Tweaks are done to Cycles kernel to have same level of inlined
> functions
> >> (new toolkit barely used inlined functions, which resulted in poor
> >> performance on all cards)
> >> - New toolkit was installed onto all release environments and buildbots.
> >>
> >> So on a positive side, next buildbot's builds will support Pascal cards,
> >> yay! :)
> >>
> >> But unfortunately, while i've managed to keep Kepler cards (GTX760) same
> >> performance as before, we had a report from Jens in IRC about Maxwell
> cards
> >> having a poor performance yet again (in his case, up to 40% worse).
> >>
> >> This is really unacceptable, we'll keep working on solution for this
> >> issue. It might take some time, so just be aware and please be patient
> :)
> >>
> >> I will keep posted here with our progress.
> >>
> >> --
> >> With best regards, Sergey Sharybin
> >>
> >
> >
> >
> >--
> >With best regards, Sergey Sharybin
> >_______________________________________________
> >Bf-committers mailing list
> >Bf-committers at blender.org
> >https://lists.blender.org/mailman/listinfo/bf-committers
> >
> >
> >
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>



-- 
With best regards, Sergey Sharybin