Um, the counter starts initialized at one. Brian
On Nov 22, 2010, at 9:32 AM, Jeff Squyres wrote: > A user noticed a specific change that we made between 1.4.2 and 1.4.3: > > https://svn.open-mpi.org/trac/ompi/changeset/23448 > > which is from CMR https://svn.open-mpi.org/trac/ompi/ticket/2489, and > originally from trunk https://svn.open-mpi.org/trac/ompi/changeset/23434. I > removed the opal_progress_event_users_decrement() from ompi_mpi_init() > because the ORTE DPM does its own _increment() and _decrement(). > > However, it seems that there was an unintended consequence of this -- look at > the annotated Ganglia graph that the user sent (see attached). In 1.4.2, all > of the idle time was "user" CPU usage. In 1.4.3, it's split between user and > system CPU usage. The application that he used to test is basically an init > / finalize test (with some additional MPI middleware). See: > > http://www.open-mpi.org/community/lists/users/2010/11/14773.php > > Can anyone think of why this occurs, and/or if it's a Bad Thing? > > If removing this decrement enabled a bunch more system CPU time, that would > seem to imply that we're calling libevent more frequently than we used to > (vs. polling the opal event callbacks), and therefore that there might now be > an unmatched increment somewhere. > > Right...? > > -- > Jeff Squyres > jsquy...@cisco.com > For corporate legal information go to: > http://www.cisco.com/web/about/doing_business/legal/cri/ > <openmpi143.jpeg><ATT00002..txt> -- Brian W. Barrett Dept. 1423: Scalable System Software Sandia National Laboratories
