Awesome -- many thanks both Ralph and Orion! On Apr 29, 2013, at 1:04 PM, Ralph Castain <r...@open-mpi.org> wrote:
> > On Apr 27, 2013, at 7:37 PM, Orion Poplawski <or...@cora.nwra.com> wrote: > >> On 04/26/2013 08:53 PM, Ralph Castain wrote: >>> >>> On Apr 26, 2013, at 7:40 PM, Orion Poplawski <or...@cora.nwra.com> wrote: >>> >>>> On 04/25/2013 04:48 AM, Jeff Squyres (jsquyres) wrote: >>>>> Orion -- >>>>> >>>>> I would just caution against using Open MPI with a thread-enabled >>>>> libevent. In most cases, the performance impact wouldn't matter, but the >>>>> whole point of MPI is to be high performance. The current 1.7 series >>>>> does *not* use a thread-enabled libevent because it detracts from >>>>> performance. Hence, using a thread-enabled libevent detracts from Open >>>>> MPI's main purpose. >>>>> >>>>> If Open MPI is suddenly bundled with a thread-enabled libevent, >>>>> *performance will go down* and users will be unhappy. We have learned >>>>> painfully over the years that users expect good performance out of the >>>>> box -- if they have get "bad" performance out of the box and have to do >>>>> something special to enable "good" performance, they'll be annoyed and >>>>> blame Open MPI. >>>>> >>>>> So I would request that you do *not* link Open MPI against a >>>>> thread-enabled libevent until we are able integrate such functionality >>>>> properly, and take measures to mitigate the performance implications >>>>> (which likely won't be until at least the 1.9 series). >>>> >>>> So, the Fedora Packaging committee has taken that part to heart, but not >>>> the bundling: >>>> >>>> * Bundling exception for libevent in openmpi - >>>> https://fedorahosted.org/fpc/ticket/273 (spot, 16:16:52) >>>> * ACTION: FPC is pretty universally against this bundling, spot will >>>> try to make a libevent-nothread.so and update libevent. (spot, >>>> 16:26:38) >>> >>> Just for clarification: who or what is "spot"? >> >> Tom "spot" Callaway - one the packaging committee members >> >>>> >>>> So it looks like I will need to shortly be looking at how to link against >>>> an external libevent. Any help with that would be greatly appreciated. >>> >>> As I said, I'll take a look at it, but can't commit to having it available >>> any time soon. It isn't something I would suggest someone try who isn't >>> fully versed in OMPI's code base. >> >> Yeah, I'm not looking forward to it. I get to at least wait until the >> non-threaded version of libevent is available. > > I hate to see someone suffer, so I went ahead and added the external libevent > connection this morning. Not trivial, but it seems to work. It is in our > developer's trunk if you want to test it. As Jeff has said, we would prefer > you not do this until the 1.9 series is released, and we won't be porting > this change to the 1.7 series anyway. > > Just put it in so we can begin the investigation, and we always appreciate > input and help in exploring the impacts! > Ralph > > >> >> -- >> Orion Poplawski >> Technical Manager 303-415-9701 x222 >> NWRA/CoRA Division FAX: 303-415-9702 >> 3380 Mitchell Lane or...@cora.nwra.com >> Boulder, CO 80301 http://www.cora.nwra.com >> _______________________________________________ >> devel mailing list >> de...@open-mpi.org >> http://www.open-mpi.org/mailman/listinfo.cgi/devel > > > _______________________________________________ > devel mailing list > de...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/devel -- Jeff Squyres jsquy...@cisco.com For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/
