On Apr 12, 2010, at 11:10 AM, Oliver Geisler wrote: > > Is the /tmp filesystem on NFS by any chance? > > Yes, /tmp is on NFS .. those are diskless nodes all without disks and > no swap space mounted.
Ah, that could do it. Open MPI's shared memory files are under /tmp. So if /tmp is NFS, you could get extremely high latencies because of dirty page writes out through NFS. You don't necessarily have to make /tmp disk-full -- if you just make OMPI's session directories go into a ramdisk instead of to NFS, that should also be sufficient. -- Jeff Squyres jsquy...@cisco.com For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/
