I assume that process binding is enabled for both mpirun and srun? If not that could account for a difference between the runtimes.
-Nathan ________________________________________ From: devel [devel-boun...@open-mpi.org] on behalf of Ralph Castain [r...@open-mpi.org] Sent: Thursday, September 05, 2013 8:19 AM To: Open MPI Developers Subject: Re: [OMPI devel] Open-MPI build of NAMD launched from srun over 20% slowed than with mpirun No, nothing significant there. Afraid I've exhausted my thoughts on why the difference might exist. Anyone else care to chime in? On Sep 4, 2013, at 9:34 PM, Christopher Samuel <sam...@unimelb.edu.au> wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Hi Ralph, > > On 05/09/13 12:50, Ralph Castain wrote: > >> Jeff and I were looking at a similar issue today and suddenly >> realized that the mappings were different - i.e., what ranks are >> on what nodes differs depending on how you launch. You might want >> to check if that's the issue here as well. Just launch the >> attached program using mpirun vs srun and check to see if the maps >> are the same or not. > > Very interesting, the ranks to node mappings are identical in all > cases (mpirun and srun for 1.6.5 and my test 1.7.3 snapshot) but what > is different is as follows. > > > For the 1.6.5 build I see mpirun report: > > number 0 universe size 64 universe envar 64 > > whereas srun report: > > number 1 universe size 64 universe envar NULL > > > > For the 1.7.3 snapshot both report "number 0" so the only difference > there is that mpirun has: > > envar 64 > > whereas srun has: > > envar NULL > > > Are these differences significant? > > I'm intrigued that the problem child (srun 1.6.5) is the only one > where number is 1. > > All the best, > Chris > - -- > Christopher Samuel Senior Systems Administrator > VLSCI - Victorian Life Sciences Computation Initiative > Email: sam...@unimelb.edu.au Phone: +61 (0)3 903 55545 > http://www.vlsci.org.au/ http://twitter.com/vlsci > > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.4.11 (GNU/Linux) > Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ > > iEYEARECAAYFAlIoCesACgkQO2KABBYQAh+0NACeK9uyDk3UZerufAopuQRxhR/T > 4skAmwS/X+8jNOPlGt4H/t5yRK8vmMer > =8TGu > -----END PGP SIGNATURE----- > _______________________________________________ > devel mailing list > de...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/devel _______________________________________________ devel mailing list de...@open-mpi.org http://www.open-mpi.org/mailman/listinfo.cgi/devel
