Thank you and one last question. Is it possible to avoid a core and instruct OMPI to use only the other cores?
On Mon, Dec 22, 2014 at 2:08 PM, Ralph Castain <r...@open-mpi.org> wrote: > > On Dec 22, 2014, at 10:45 AM, Saliya Ekanayake <esal...@gmail.com> wrote: > > Hi Ralph, > > Yes the report bindings show the correct binding as expected for the > processes. The doubt I am having is, say I spawn a thread within my > process. If I don't specify affinity for it, is it possible for it to get > scheduled to run in a core outside that of the process? > > > It shouldn’t, unless you deliberately unbind it. > > > Second question is, does MPI provides an API such that I can retrieve the > binding info from program to take decisions on setting thread affinity? > > > Nothing specifically in the standard, no. There has been some discussion > on this list about ways of getting the info, though they all involve a > collective operation. I’m working on an MPI extension for OMPI to access it > as each proc already has binding/location info for every proc in the job - > just no MPI standard way of providing it to you. > > > > Thank you, > Saliya > > On Mon, Dec 22, 2014 at 1:18 PM, Ralph Castain <r...@open-mpi.org> wrote: > >> FWIW: it looks like we are indeed binding to core if PE is set, so if you >> are seeing something different, then we may have a bug somewhere. >> >> If you add —report-bindings to your cmd line, you should see where we >> bound the procs - does that look correct? >> >> >> On Dec 22, 2014, at 9:49 AM, Ralph Castain <r...@open-mpi.org> wrote: >> >> They will be bound to whatever level you specified - I believe by default >> we bind to socket when mapping by socket. If you want them bound to core, >> you might need to add —bind-to core. >> >> I can take a look at it - I *thought* we had reset that to bind-to core >> when PE=N was specified, but maybe that got lost. >> >> >> On Dec 22, 2014, at 8:32 AM, Saliya Ekanayake <esal...@gmail.com> wrote: >> >> Hi, >> >> I've been using --map-by socket:PE=N, where N is used to control the >> number of cores a proc gets mapped to. Does this also guarantee that a proc >> is bound to N cores in the socket? I am asking this because I see some >> threads spawned by the process run outside the given N cores in the socket. >> >> Is this expected or I guess I am missing some binding parameter here? >> Also, is there some documentation on these different choices? Are the >> options in [1] available in current release? >> >> [1] >> http://www.slideshare.net/jsquyres/open-mpi-explorations-in-process-affinity-eurompi13-presentation >> >> Thank you, >> Saliya >> >> -- >> Saliya Ekanayake >> Ph.D. Candidate | Research Assistant >> School of Informatics and Computing | Digital Science Center >> Indiana University, Bloomington >> Cell 812-391-4914 >> http://saliya.org >> _______________________________________________ >> users mailing list >> us...@open-mpi.org >> Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users >> Link to this post: >> http://www.open-mpi.org/community/lists/users/2014/12/26051.php >> >> >> >> >> _______________________________________________ >> users mailing list >> us...@open-mpi.org >> Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users >> Link to this post: >> http://www.open-mpi.org/community/lists/users/2014/12/26054.php >> > > > > -- > Saliya Ekanayake > Ph.D. Candidate | Research Assistant > School of Informatics and Computing | Digital Science Center > Indiana University, Bloomington > Cell 812-391-4914 > http://saliya.org > _______________________________________________ > users mailing list > us...@open-mpi.org > Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users > Link to this post: > http://www.open-mpi.org/community/lists/users/2014/12/26056.php > > > > _______________________________________________ > users mailing list > us...@open-mpi.org > Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users > Link to this post: > http://www.open-mpi.org/community/lists/users/2014/12/26057.php > -- Saliya Ekanayake Ph.D. Candidate | Research Assistant School of Informatics and Computing | Digital Science Center Indiana University, Bloomington Cell 812-391-4914 http://saliya.org
