[petsc-users] GPU local direct solve of penta-diagonal

[Dominic Meiser]

On 12/12/2013 04:38 PM, Paul Mullowney wrote:
> Provided you have a good parallel sparse direct solve for a single SM, 
> you could unleash 32 direct solves (or perhaps 16) which run 
> concurrently on the K20x. One only needs to set an environment 
> variable to use Hypre Q
On Titan all you need to do is
|
$ export CRAY_CUDA_PROXY=1

|

See here:
https://www.olcf.ornl.gov/tutorials/cuda-proxy-managing-gpu-context/

Cheers,
Dominic
>
> I don't know of any good parallel sparse direct solver for small systems.
>
> -Paul
>
>
> On Thu, Dec 12, 2013 at 4:29 PM, Dominic Meiser <dmeiser at txcorp.com 
> <mailto:dmeiser at txcorp.com>> wrote:
>
>     Hi Karli,
>
>
>     On 12/12/2013 02:50 PM, Karl Rupp wrote:
>>
>>     Hmm, this does not sound like something I would consider a good
>>     fit for GPUs. With 16 MPI processes you have additional
>>     congestion of the one or two GPUs per node, so you would have the
>>     rethink the solution procedure as a whole.
>>
>     Are you sure about that for Titan? Supposedly the K20X's can deal
>     with multiple MPI processes hitting a single GPU pretty well using
>     Hyper-Q. Paul has seen pretty good speed up with small GPU kernels
>     simply by over-subscribing each GPU with 4 MPI processes.
>
>     See here:
>     http://blogs.nvidia.com/blog/2012/08/23/unleash-legacy-mpi-codes-with-keplers-hyper-q/
>
>
>     Cheers,
>     Dominic
>
>
>     -- 
>     Dominic Meiser
>     Tech-X Corporation
>     5621 Arapahoe Avenue
>     Boulder, CO 80303
>     USA
>     Telephone:303-996-2036  <tel:303-996-2036>
>     Fax:303-448-7756  <tel:303-448-7756>
>     www.txcorp.com  <http://www.txcorp.com>
>
>


-- 
Dominic Meiser
Tech-X Corporation
5621 Arapahoe Avenue
Boulder, CO 80303
USA
Telephone: 303-996-2036
Fax: 303-448-7756
www.txcorp.com

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20131212/be81dea1/attachment-0001.html>