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-   -   Parallel with Windoze, speed difference between PV (http://www.cfd-online.com/Forums/cfx/21065-parallel-windoze-speed-difference-between-pv.html)

Charles March 9, 2005 08:43

Parallel with Windoze, speed difference between PV
 
I am running CFX 5.7.1 parallel on a mixed cluster of machines, all with Windows. The cluster consists of a dual Xeon 3.6, a quad Opteron 248 and 5 3.2 GHz P4's. Some of the tests that I have run have shown a dramatic improvement in wallclock time when going from PVM to MPI. Can anybody throw some light on this? I vaguely recall somebody once mentioning that PVM on Windows is not nearly as quick as on Linux?

Glenn Horrocks March 9, 2005 17:24

Re: Parallel with Windoze, speed difference betwee
 
Hi,

On windows machines MPICH for windows is usually much faster than PVM. In my benchmarking running MPICH on windows is roughly the same speed as running PVM on Linux. I have no idea why the difference, but that's the end result.

Glenn Horrocks

Neale March 9, 2005 22:42

Re: Parallel with Windoze, speed difference betwee
 
The PVM implementation really sucks on Windows and is especially bad when you run on dual Xeons. MPICH is better but is less stable.

On a quad opteron you should be seeing superlinear performance if your case is big enough (PVM or MPICH)


Charles March 10, 2005 02:25

Re: Parallel with Windoze, speed difference betwee
 
Thanks guys, your comments are very much in line with what I've been observing.


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