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From: David Gunter (dog_at_[hidden])
Date: 2006-02-02 10:32:42


I would like see more of such results. In particular it would be
nice to see a comparison of OpenMPI to the newer MPICH2.

Thanks, Glen.

-david

--
David Gunter
CCN-8: HPC Environments - Parallel Tools
On Feb 2, 2006, at 6:55 AM, Glen Kaukola wrote:
> Hi everyone,
>
> I recently took Open MPI (1.0.2a4) for a spin and thought you all  
> might
> like to see how it's currently stacking up against MPICH  
> (1.2.7p1).  The
> benchmark I used was the EPA's CMAQ (Community Multiscale Air Quality)
> model.
>
> Now bear in mind my results aren't completely scientific.  For one  
> thing
> I'd need to run a series of jobs and take the averages.  Forgive me if
> I'm too lazy to do that.  I also didn't go through the trouble of
> completely isolating my jobs while they were running.  However, I did
> monitor them pretty closely and I'm fairly certain no jobs from other
> users crept in on the machines I was using.
>
> Anyway, without further ado, here are my results (in h:mm):
>
> Open MPI
> 1 cpu job: 2:38
> 2 cpu job: 1:26
> 4 cpu job: 1:38
> 8 cpu job: 1:08
> 36 cpu job: 3:09
>
> MPICH
> 1 cpu job: 2:38
> 2 cpu job: 1:27
> 4 cpu job: 0:48
> 8 cpu job: 0:32
>
> And while Open MPI does seem a bit slower, one real nice thing I  
> can say
> is that a 16+ cpu job runs without a hitch.  I could never get away  
> with
> that while using MPICH, as the jobs would just crash.  Whether  
> MPICH is
> at fault, or the CMAQ code is buggy, or gigabit ethernet just isn't  
> good
> enough, I really couldn't say.  But Open MPI sure doesn't seem to have
> that problem.
>
> It's also rather odd how the 4 cpu Open MPI job takes longer than  
> the 2
> cpu Open MPI job.  In fact that's slightly faster compared to the  
> first
> time I ran a 4 cpu Open MPI job (I couldn't believe it the first  
> time so
> I reran that one).
>
> And on a totally unrelated note, after swapping out MPICH for Open  
> MPI,
> I can't seem to background my scripts.  When I do my shell (bash)  
> tells
> me the job has stopped.  Somewhat annoying.
>
> Anyway, keep up the good work.  I'll be paying close attention, and
> hopefully see some speedups in the not too distant future.
>
>
> Glen
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