Ah, that sheds some light. There is indeed a significant change between earlier releases and the 1.8.1 and above that might explain what he is seeing. Specifically, we no longer hammer the cpu while in MPI_Finalize. So if 16 of the procs are finishing early (which the output would suggest), then they will go into a "lazy" finalize state while they wait for the rest of the procs to complete their work.
In contrast, prior releases would continue at 100% cpu while they polled to see if the other procs were done. We did this to help save power/energy, and because users had asked why the cpu utilization remained at 100% even though procs were waiting in finalize HTH Ralph On Aug 21, 2014, at 5:55 PM, Christopher Samuel <sam...@unimelb.edu.au> wrote: > On 22/08/14 10:43, Ralph Castain wrote: > >> From your earlier concerns, I would have expected only to find 32 of >> them running. Was that not the case in this run? > > As I understand it in his original email he mentioned that with 1.6.5 > all 48 processes were running at 100% CPU and was wondering if the buggy > BIOS that caused hwloc the issues he reported on the hwloc-users list > might be the cause for this regression in performance. > > 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 > > _______________________________________________ > devel mailing list > de...@open-mpi.org > Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/devel > Link to this post: > http://www.open-mpi.org/community/lists/devel/2014/08/15686.php
