Hi Robert,
Hakon Bugge presented a paper on this at ISC09. He found that SMT helped
several SPEC MPI benchmarks. (He used Platform MPI, not Open MPI.)
He did not oversubscribe, though. He just enabled SMT, which allowed the OS to
allocate spare CPU cycles during IO wait, etc.
My conclusions
Hi Gus,
For single node runs, don't bother specifying the btl. Openmpi should select
the best option.
Beyond that, the "80% total RAM" recommendation is misleading. Base your N off
the memfree rather than memtotal. IB can reserve quite a bit. Verify your
/etc/security/limits.conf limits allo
Hi Iftikhar,
For HPL, try writing a bash script that pins processes to their local memory
controllers using numactl before kicking off HPL. This is particularly helpful
when spawning more than 1 thread per process. The last line of your script
should look like "numactl -c $cpu_bind -m $ mem_b
Hi Jeff,
Yes, this technique is particularly helpful for multi-threaded and works
consistently across the various MPIs I test.
Thanks, jacob
> -Original Message-
> From: users-boun...@open-mpi.org [mailto:users-boun...@open-mpi.org] On
> Behalf Of Jeff Squyres
> Sent: Wednesday, June 0
