As stated at the conf call, I did some performance testing on a 32 cores
node.
So, here is graph showing 500 timings of an allreduce operation (repeated
15,000 times for good timing) with sysv, mmap on /dev/shm and mmap on
/tmp.
What is shows :
- sysv has the better performance ;
- having the mmap file in /dev/shm is very close to sysv. We only have
+0.1 us for a complete allreduce operation, but it seems stable. The noise
is identical to sysv (must be OS noise) ;
- having the mmap file in /tmp (ext3) decreases performance (+0.4 us
compared to /dev/shm) and seems prone to some "other" noise.
Warning : the graph does not start at 0.
Sylvain
On Tue, 27 Apr 2010, Samuel K. Gutierrez wrote:
Hi,
With Jeff and Ralph's help, I have completed a System V shared memory
component for Open MPI. I have conducted some preliminary tests on our
systems, but would like to get test results from a broader audience.
As it stands, mmap is the defaul, but System V shared memory can be activated
using: -mca mpi_common_sm sysv
Repository:
http://bitbucket.org/samuelkgutierrez/ompi_sysv_sm
Input is greatly appreciated!
--
Samuel K. Gutierrez
Los Alamos National Laboratory
_______________________________________________
devel mailing list
de...@open-mpi.org
http://www.open-mpi.org/mailman/listinfo.cgi/devel
