Hi Terry, I would like to run a paraview-server all time on our cluster (even though it is not in use 24h) - but this would simply result in some kind of "heating-thread".
Even though it has (in theory) no impact on the node performace (which is part of a grid-engine), it would simply result in some kind of "heating-thread" which is not a nice idea. Greetings Jens Terry Frankcombe schrieb: > As Eugene said: Why are you desperate for an idle CPU? Is it not > yielding to other processes? > > > On Mon, 2008-12-08 at 10:01 +0100, Jens wrote: >> Hi Douglas, >> >> this an answer to my question on the paraview-mailinglist. >> >> I have the same problem with paraview, that it simply waits for more to >> do in client-server(MPI) mode, but is running on 100%. >> >> Different MPI-Implementations seem to behave different here. Using >> MPICH2 for example does not result in 100% cpu-time for paraview while >> waiting. >> >> I desperate to know if that is possible with open-mpi, too. These FAQs >> where interesting, but did not help: >> http://www.open-mpi.org/faq/?category=running#oversubscribing >> http://www.open-mpi.org/faq/?category=running#force-aggressive-degraded >> >> Greetings >> Jens >> >> Eugene Loh schrieb: >>> Douglas Guptill wrote: >>> >>>> Hi: >>>> >>>> I am using openmpi-1.2.8 to run a 2 processor job on an Intel >>>> Quad-core cpu. Opsys is Debian etch. I am reaonably sure that, most >>>> of the time, one process is waiting for results from the other. The >>>> code is fortran 90, and uses mpi_send and mpi_recv. Yet >>>> "gnome-system-monitor" shows 2 cpus at 100%. >>>> >>>> So I read, and re-read, the FAQs, and found the mpi_yield_when_idle >>>> flag, and tried it: >>>> >>>> mpirun --host localhost,localhost,localhost,localhost --mca btl >>>> sm,self --mca mpi_yield_when_idle 1 --byslot -np 2 >>>> /home/dguptill/software/sopale_nested_2008-10-24/bin/sopale_nested_openmpi-intel-noopt >>>> >>>> >>>> And still get, for each run, two cpus are at 100%. >>>> >>>> My goal is to get the system to a minimum usage state, where only one >>>> cpu is being used, if one process is waiting for results from the >>>> other. >>>> >>>> Can anyone suggest if this is possible, and if so, how? >>>> >>>> >>> I'm no expert on this, but I've played with the same problem. I think I >>> did this on Solaris, but perhaps the behavior is the same on other OSes. >>> >>> One issue is that "yield" might mean "yield if there is someone else >>> ready to run". Like a traffic sign: if someone else is there, you >>> yield. If no one else is there, there's no way to tell that someone is >>> yielding. >>> >>> Next, even if someone else is trying to run, "yield" doesn't give give >>> up the CPU 100%. It's still rather pesky. >>> >>> So, one question is whether you really want to have an idle CPU. Do >>> you, or do you simply want another process, if there is one, to be able >>> to run? >>> >>> Not a real answer to your question, but hopefully this helps. >>> _______________________________________________ >>> users mailing list >>> us...@open-mpi.org >>> http://www.open-mpi.org/mailman/listinfo.cgi/users >>> >> _______________________________________________ >> users mailing list >> us...@open-mpi.org >> http://www.open-mpi.org/mailman/listinfo.cgi/users > > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users >
