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Re: [charm] Run multiple charm executables simultaneously


Chronological Thread 
  • From: Jozsef Bakosi <jbakosi AT gmail.com>
  • To: "charm AT cs.uiuc.edu" <charm AT cs.uiuc.edu>
  • Subject: Re: [charm] Run multiple charm executables simultaneously
  • Date: Tue, 28 Jul 2015 14:09:57 -0600
  • List-archive: <http://lists.cs.uiuc.edu/pipermail/charm/>
  • List-id: CHARM parallel programming system <charm.cs.uiuc.edu>

In case someone runs into the same issue, this was a problem due to the change in the default process binding in OpenMPI between versions 1.6.5 and 1.8. As it turns out, the default in 1.6.5 is "--bind-to none", while in 1.8 is "--bind-to core". While the former lets the OS do the right thing, the latter does not (in my case) and oversubscribes the first socket instead of spreading them out to all available ones. Thus with 1.8 the correct behavior can be obtained by passing "--bind-to none".

On Mon, Jul 27, 2015 at 12:53 PM, Jozsef Bakosi <jbakosi AT gmail.com> wrote:
Hi folks,

What is the simplest way to run multiple charm executables at the same time?

I'm setting up ctest to run a regression test suite and running three runs (a 1, a 2, and a 4 processor job each with charmrun +p1, +p2, and +p4) yields overloading the 7 ranks only four CPUs on an 8 core machine. I'm using mpi-linux-x86_64.

Thanks,
Jozsef




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