[mpich-discuss] Time distribution of Intel MPI Benchmark (PingPong)

["Antonio J. Peña"]

Dear Philip,

Both functions are part of MPICH. MPICH uses intentionally active 
polling to minimize the latency on communications. In short, you get 
faster communications by repeatedly checking for communication 
completion during waiting times. So, that's expected.

   Antonio


On 07/01/2014 09:16 AM, Klaus Philip wrote:
>
> Hi,
>
> I tested mpich2 3.1.1 with the Intel MPI Benchmark, more precisely the 
> "PingPong"-Benchmark.
>
> It uses the MPI_Send and MPI_Recv function to send one message from 
> /Process 1/ to /Process 2/ and back.
>
> While the benchmark was running, I executed the Sysprofiler (sysprof) 
> to check the time distribution (Picture below).
>
> My question is now, if the two marked Processes 
> (*MPID_nem_lmt_shm_progress* and *poll*) are parts of MPICH or the 
> Intel-PingPong-Benchmark, because they are both consuming much time 
> (49,03% and 19,99%).
>
> Greetings,
>
> Philip
>
>
>
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-- 
Antonio J. Peña
Postdoctoral Appointee
Mathematics and Computer Science Division
Argonne National Laboratory
9700 South Cass Avenue, Bldg. 240, Of. 3148
Argonne, IL 60439-4847
apenya at mcs.anl.gov
www.mcs.anl.gov/~apenya

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