On 4/6/2010 10:11 AM, Rainer Keller wrote: > Hello Oliver, > Hmm, this is really a teaser... > I haven't seen such a drastic behavior, and haven't read of any on the list. > > One thing however, that might interfere is process binding. > Could You make sure, that processes are not bound to cores (default in 1.4.1): > with mpirun --bind-to-none >
I have tried version 1.4.1. Using default settings and watched processes switching from core to core in "top" (with "f" + "j"). Then I tried --bind-to-core and explicitly --bind-to-none. All with the same result: ~20% cpu wait and lot longer over-all computation times. Thanks for the idea ... Every input is helpful. Oli > Just an idea... > > Regards, > Rainer > > On Tuesday 06 April 2010 10:07:35 am Oliver Geisler wrote: >> Hello Devel-List, >> >> I am a little bit helpless about this matter. I already posted in the >> user list. In case you don't read the users list, I post in here. >> >> This is the original posting: >> >> http://www.open-mpi.org/community/lists/users/2010/03/12474.php >> >> Short: >> Switching from kernel 2.6.23 to 2.6.24 (and up), using openmpi 1.2.7-rc2 >> (I know outdated, but in debian stable, and same results with 1.4.1) >> increases communication times between processes (essentially between one >> master and several slave processes). This is regardless of whether the >> processes are local only or communication is over ethernet. >> >> Did anybody witness such a behavior? >> >> Ideas what should I test for? >> >> What additional information should I provide for you? >> >> Thanks for your time >> >> oli >> > -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean.
