Rmpi and cpu usage on slaves
On Wed, 2009-04-22 at 12:55 -0400, Sean Davis wrote:
So, as Dirk suggested, the 100% CPU usage is thought to be a feature and not a bug.
As someone who just ran into this (the link to the thread was in the earlier links), I looked into why OpenMPI worked that way. I think a fairer characterization is that responsiveness while running Open MPI is a feature; the 100% CPU useage is just a side effect. Fixing it is on their todo list, but it's not a high priority because the fix is a bit tricky and the useage scenario that strikes the developers as standard reserves the CPUs for the job anyway. I don't happen to fit that scenario, but I suspect the developers are right in their judgement of typical use. If you're concerned, a number of work-arounds or brittle fixes are in the openmpi archives; the responses to my query (http://www.open-mpi.org/community/lists/users/2009/04/9016.php) have pointers to a couple of them. Ross
Ross Boylan wk: (415) 514-8146 185 Berry St #5700 ross at biostat.ucsf.edu Dept of Epidemiology and Biostatistics fax: (415) 514-8150 University of California, San Francisco San Francisco, CA 94107-1739 hm: (415) 550-1062