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>
