[petsc-dev] MIC available for testing

[Dmitry Karpeev]

Karl,

Could you get me an account as well?
I'm at INL right now and we are trying to build libmesh with petsc on a mic.
Building petsc turns out to be pretty straightforward, but libmesh is
another story.
libmesh can use tbb to parallelize FEM assembly, and I'm curious to see how
that performs.

Thanks.
Dmitry.


On Fri, Dec 14, 2012 at 2:49 PM, Karl Rupp <rupp at mcs.anl.gov> wrote:

> Hi guys,
>
> today I got a gentle introduction into our testing machine equipped with
> two Intel MICs. They are still beta, yet I could run some simple kernels in
> native mode. As an example, without any modification of existing OpenMP
> code for vector addition in double precision of 3e6 elements, I got the
> following timings:
>
> -- Native mode, i.e. all code executed on MIC --
> Single core time: 0.642 sec
> All-core time:    0.011 sec
>
> For offloaded execution (CPU <-> MIC, just like with GPUs), additional
> pragmas are required, I haven't tried that yet.
>
> For comparison, the same code on the CPU (Sandy Bridge, 8x2 cores, 2.6
> GHz) takes 0.060 sec without OpenMP and 0.030 sec with OpenMP. Thus, the
> conclusion is that one *really* needs to get all cores on the MIC busy in
> order to get the full memory bandwidth. Thus, a plain 'just recompile for
> MIC and you get good performance' won't work for most applications in
> practice, simply because the serial performance is so limited.
>
> @Shri: It would be interesting to give pthreads a try, particularly how it
> compares with OpenMP. I'll be out of the lab until the beginning of
> January, but I can help you with getting an account and getting started.
>
> Btw: I just got a call regarding Altera hardware, we might have chances to
> get our fingers on their OpenCL-enabled hardware.
>
> Best regards,
> Karli
>
>
>


-- 
Dmitry Karpeev, Ph.D.
Assistant Computational Mathematician
Mathematics and Computer Science
Argonne National Laboratory
Argonne, Illinois, USA
and
Fellow
Computation Institute
University of Chicago
5735 S. Ellis Avenue
Chicago, IL 60637
-----------------------
Phone: 630-252-1229
Fax:   630-252-5986
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