[Sidefx-houdini-list] open cl and quadro on h12

Andrew Lyons tstexture at gmail.com
Thu Aug 16 12:38:30 EDT 2012


There's probably not much tweaking that can be done in Houdini. I'm not a
GPGPU expert - but what I've learned suggests that performance mostly
hinges on the algorithms used in the Cuda/CL kernel code (threading/warp
friendly), and how often the host code (Houdini) sends data to and from the
GPU across the PCI bus (which is the biggest bottleneck). To get the touted
30 * speed-ups cited in some of the Cuda documentation, you really need to
send data to the GPU once, do a lot of stuff to it, and then bring it back
once. DOPs should be good at that - because it collapses a node tree into
one structure, and could potentially send the data to the GPU once and
operate on it in place. For the same reason, SOP trees will never be
optimal on OpenCL due to the copying from node to node that takes place.
People create some pretty wacky SOP networks. Not sure how to make a SOP
network GPGPU friendly - short of rewriting everything as DOPs.

The memory limitation issue is the other big bottleneck. I spoke to someone
from Nvidia at Siggraph about this, and they suggested that the problem is
cost. It's just really expensive to put lots of memory on a GPU, and the
only market that is clammering for it is us (CG). We're not a big market,
and so they're like - meh (my words - not theirs). On the upside, he said
that they have 6gb cards coming out next year, and as memory manufacturers
continue to find ways to increase capacity and decrease costs we'll
continue to see more on-board VRAM. That's just Nvidia though. Maybe some
other board manufacturer will work out how to access 200 gig of ram
efficiently from a streaming multiprocessor...

http://www.anandtech.com/show/5493/amd-outlines-hsa-roadmap-unified-memory-for-cpugpu-in-2013-hsa-gpus-in-2014

Cheers


On 16 August 2012 08:51, Jordan Halsey <jordanhalsey at gmail.com> wrote:

> I am curious about what tweaking can be done in Houdini to maximize the
> potential on the GPU as well.
>
> I have a quadro 6000 at work on dual Zeons  and to tell the truth we are
> all disappointed with the cards and their performance. I have always felt
> like something is not quite right...the machines are made by Boxx and it
> just does not make much sense to me with the quality of all the hardware.
> We have tested it along side sli'd 580's and 670's in Touch Designer and
> saw better performance on the lower end cards.
>
> Initially the machine had two Quadro 6000's sli'd
>
>
>
> On Thu, Aug 16, 2012 at 8:28 AM, Alvaro Castaneda <varomix at gmail.com>
> wrote:
>
> > Hey Michael,
> > are there any differences when switching?, like the sim been different
> > cause is a different
> > code, I guess the question is, is there any noticeable difference?
> >
> > Cheers!!
> >
> >
> > On Thu, Aug 16, 2012 at 9:26 AM, Michael O'Brien <mobrien at pixar.com>
> > wrote:
> >
> > > Hola~
> > >
> > > That's in line with what we are seeing. We try to stay on the GPU for
> > > testing, but then go to the CPU for final tweaking.
> > >
> > > MO
> > >
> > > > -----Original Message-----
> > > > From: sidefx-houdini-list-bounces at sidefx.com [mailto:
> > > sidefx-houdini-list-
> > > > bounces at sidefx.com] On Behalf Of Nick van Zutphen
> > > > Sent: Thursday, August 16, 2012 2:34 AM
> > > > To: sidefx-houdini-list at sidefx.com
> > > > Subject: Re: [Sidefx-houdini-list] open cl and quadro on h12
> > > >
> > > > It depends, the computations on the gpu are limited to the VRAM on
> the
> > > > videocard. Compared to your CPU and ram that is quite a limitation.
> > > > On my machine the 580gtx 3gb is 30% faster than when I compute a
> > similar
> > > > sim on the CPU. How ever due to the VRAM limitation I can't go beyond
> > > > about 256x256 voxels on the GPU.
> > > >
> > > > Cheers,
> > > > Nick
> > > >
> > > > On 16 aug. 2012, at 10:44, zoran arizanovic <
> > zoran.arizanovic at gmail.com>
> > > > wrote:
> > > >
> > > > > hi
> > > > > i have a new dual xeon , 96 gb ram machine now built for sim work i
> > > > > just need to use it to its maximum and was wondering if this cl
> would
> > > > > speed it up
> > > > >
> > > > > did anyone have any luck with running cl switch ?
> > > > > I have quadro 4000 would this be ok for cl?they say it has fermi
> > arch.
> > > > > but still when i switch it on i get error what version of drivers
> are
> > > > > you using for this?
> > > > >
> > > > > i have a new dual xeon , 96 gb ram machine now built for sim work i
> > > > > just need to use it to its maximum and was wondering if this cl
> would
> > > > > speed it up
> > > > >
> > > > > --
> > > > > Zoran Arizanovic
> > > > > vfx reel : http://vimeo.com/28605448
> > > > > http://www.imdb.com/name/nm2902303/
> > > > > _______________________________________________
> > > > > Sidefx-houdini-list mailing list
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> > > > >
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>
>
>
> --
> **
> *Jordan Halsey**
> *
> maya | houdini | nuke | ae
> *www.jordanhalsey.com*
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>



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Andrew D Lyons | Digital Artist | http://www.linkedin.com/in/tstex
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