[petsc-users] Very poor speed up performance

[Yongjun Chen]

On Wed, Dec 22, 2010 at 5:48 PM, Satish Balay <balay at mcs.anl.gov> wrote:

> On Wed, 22 Dec 2010, Yongjun Chen wrote:
>
> > Satish,
> >
> > I have reconfigured the PETSC with –download-mpich=1 and
> > –with-device=ch3:sock. The results show that the speed up can now remain
> > increasing when computing cores increase from 1 to 16. However, the
> maximum
> > speed up is still only around 6.0 with 16 cores. The new log files can be
> > found in the attachment.
>
> Perhaps this was mentioned eariler. Performance doesn't scale with
> number of cores. [its depends on both scalable compute unites -aka
> cores, as well as scalable memory modules]
>
> When the hardware is not designed to provide scalable performance -
> expecting it is wrong. The goal should be to extract max performance
> out of a given piece of hardware - not scalable performance.
>
Wrt with-device=ch3:sock - it might not be the best performer for
> shared memory Try the default 'device=ch3:nemsis'
>
> Satish



I am now trying with --with-device=ch3:nemsis. Hope it can have a little
better performance
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20101222/3f9669af/attachment-0001.htm>