On our SGI system here i've noticed the same thing.. It doesn't seem to impact paraview's performance, but no matter what's going on all the processes are pegged at 100% utilization.<br><br>It'd kinda funny in a way to see the utilization actually *drop* when they start doing real work.
<br><br><div><span class="gmail_quote">On 4/18/06, <b class="gmail_sendername">John Patchett</b> <<a href="mailto:patchett@lanl.gov">patchett@lanl.gov</a>> wrote:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
It's probably MPICH, we have also witnessed the CPU spinning using<br>MVAPICH. We wrote some code that found nodes with open receives show<br>high usage. This makes sense that process 0 shows normal CPU usage<br>while the rest of the nodes in the job have open receives while waiting
<br>for process 0 to tell them to do something. I believe the behavior<br>causing the high CPU usage is called polling and you can build MVAPICH<br>(as well as MPICH??) with polling turned off. I understand this will<br>
simply increase your latency.<br><br>-John<br><br>On Apr 18, 2006, at 12:22 PM, Sean Ziegeler, Contractor wrote:<br><br>>> I tried to run paraview which was compiled with mpich. I noticed that<br>>> cpu usage on paraview data servers (pvserver) is always around 99%
<br>>> even though no data processing at all. Only the first pvdataserver's<br>>> cpu usage was reasonable(where I started the mpirun command).<br>>><br>>> Why did that happen? Does that mean paraview is not working properly
<br>>> on all paraivew data servers.<br>><br>> That might be an MPI issue. We use MVAPICH (a derivative of MPICH) and<br>> it also seems to peg-out the processors for all but the first process.<br>> This happens with any MPI run, not just Paraview. I am guessing MPI is
<br>> doing some sort of spin-wait on those processes.<br>><br>> Anyway, to see if it truly is MPICH, you can try running some other MPI<br>> program that can idle for a certain amount of time and see if those
<br>> processes behave similarly.<br>><br>> -Sean<br>><br>> _______________________________________________<br>> ParaView mailing list<br>> <a href="mailto:ParaView@paraview.org">ParaView@paraview.org
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