[mpich-discuss] Poor MPICH Performance on Windows Vista vs. XP

[Rahul Mukerjee]

Hi Jayesh,

I installed the latest release, 1.2 of MPICH2 on the Vista machines.
The -channel nemesis option showed impressive gains. Here are the
results:

3 hosts: Time = 0.354110 secs
4 hosts: Time = 13.612531 secs
5 hosts: Time = 13.849166 secs

With -channel nemesis:
3 hosts: Time = 0.045664 secs
4 hosts: Time = 0.253233 secs
5 hosts: Time = 0.270557 secs

Can you please tell me what exactly was the issue here? Also, I am yet
to test on the XP machines but I am assuming that this option will
perform equally well there. Is that correct? And finally, I'd also
like to mention that I had seen very poor scalability for my
application on a quad-core machine with the -localonly option. I hope
to see some dramatic improvements with the 'nemesis'. Please correct
me if I am wrong.

Thank you very much for your help.

Sincerely,

Rahul Mukerjee.

On Thu, Oct 29, 2009 at 12:52 PM, Jayesh Krishna <jayesh at mcs.anl.gov> wrote:
> Hi,
>  Oh... and try the latest stable release, 1.2, of MPICH2 (1.0.8 is old) available at http://www.mcs.anl.gov/research/projects/mpich2/downloads/index.php?s=downloads .
>  Let us know your findings.
>
> (PS: With WinXP make sure that you have SP3 installed before installing MPICH2.)
> Regards,
> Jayesh
> ----- Original Message -----
> From: "Jayesh Krishna" <jayesh at mcs.anl.gov>
> To: "r mukerjee" <r.mukerjee at gmail.com>
> Cc: mpich-discuss at mcs.anl.gov
> Sent: Thursday, October 29, 2009 12:47:39 PM GMT -06:00 US/Canada Central
> Subject: Re: [mpich-discuss] Poor MPICH Performance on Windows Vista vs. XP
>
> Hi,
>  Did you try the nemesis channel (mpiexec -n 2 -channel nemesis barrier_test.exe)?
>
> Regards,
> Jayesh
> ----- Original Message -----
> From: "Rahul Mukerjee" <r.mukerjee at gmail.com>
> To: mpich-discuss at mcs.anl.gov
> Sent: Thursday, October 29, 2009 12:17:01 PM GMT -06:00 US/Canada Central
> Subject: [mpich-discuss] Poor MPICH Performance on Windows Vista vs. XP
>
> Hi,
>
> I am using MPICH2 version 1.0.8p1. I am using a simple C code to
> measure the time taken for 100 MPI_BARRIER calls in Windows Vista vs.
> XP. Here is the code:
>
> #include "mpi.h"
> #include <stdio.h>
> #include <stdlib.h>
> int main(int argc, char **argv)
> {
>    int cpuid, ncpu;
>    int i, count;
>    double t1, t2, sum;
>    count = 100;
>    sum = 0.0;
>    MPI_Init(&argc, &argv);
>    MPI_Comm_size(MPI_COMM_WORLD, &ncpu);
>    MPI_Comm_rank(MPI_COMM_WORLD, &cpuid);
>    printf("NCPU:%d, CPUID:%d\n", ncpu, cpuid);
>    fflush(stdout);
>    printf("start barrier\n"); fflush(stdout);
>    for (i=0; i<count; i++)
>        {
>                t1 = MPI_Wtime();
>                MPI_Barrier(MPI_COMM_WORLD);
>                t2 = MPI_Wtime();
>                if (cpuid == 0) sum = sum + (t2 - t1);
>        }
>        printf("end barrier\n"); fflush(stdout);
>        if (cpuid == 0) printf("Time = %lf\n", sum);
>        MPI_Finalize();
>    return 0;
> }
>
> The results are:
>
> Windows XP:
> 3 hosts: Time = 0.034093 secs
> 4 hosts: Time = 0.041328 secs
>
> Windows Vista:
> 3 hosts: Time = 0.347072 secs (Slow, but still bearable)
> 4 hosts: Time = 11.820926 secs (WTF???)
>
> Someone had posted earlier about poor MPICH performance with HPC
> Server 2008 / Vista. This is in continuation of that, in a way. Any
> help would be greatly appreciated. Thank you.
>
> Sincerely,
>
> Rahul Mukerjee.
> _______________________________________________
> mpich-discuss mailing list
> mpich-discuss at mcs.anl.gov
> https://lists.mcs.anl.gov/mailman/listinfo/mpich-discuss
> _______________________________________________
> mpich-discuss mailing list
> mpich-discuss at mcs.anl.gov
> https://lists.mcs.anl.gov/mailman/listinfo/mpich-discuss
>