“Supposedly faster” isn’t a particularly good reason to change MPI implementations but canceling sends is hard for reasons that have nothing to do with performance.
Also, I’d not be so eager to question the effectiveness of Open-MPI on InfiniBand. Check the commit logs for Mellanox employees some time. Jeff On Wed, Oct 2, 2019 at 7:46 AM Emyr James via users < users@lists.open-mpi.org> wrote: > Hi Christian, > > > I would suggest using mvapich2 instead. It is supposedly faster than > OpenMpi on infiniband and it seems to have fewer options under the hood > which means less things you have to tweak to get it working for you. > > > Regards, > > > Emyr James > Head of Scientific IT > CRG -Centre for Genomic Regulation > C/ Dr. Aiguader, 88 > <https://www.google.com/maps/search/C%2F+Dr.+Aiguader,+88?entry=gmail&source=g> > Edif. PRBB > 08003 Barcelona, Spain > Phone Ext: #1098 > > ------------------------------ > *From:* users <users-boun...@lists.open-mpi.org> on behalf of Christian > Von Kutzleben via users <users@lists.open-mpi.org> > *Sent:* 02 October 2019 16:14:24 > *To:* users@lists.open-mpi.org > *Cc:* Christian Von Kutzleben > *Subject:* [OMPI users] problem with cancelling Send-Request > > Hi, > > I’m currently evaluating to use openmpi (4.0.1) in our application. > > We are using a construct like this for some cleanup functionality, to > cancel some Send requests: > > *if* (*req != MPI_REQUEST_NULL) { > MPI_Cancel(req); > MPI_Wait(req, MPI_STATUS_IGNORE); > assert(*req == MPI_REQUEST_NULL); > } > > However the MPI_Wait hangs indefinitely and I’ve debugged into it and I > came across this in pml_ob1_sendreq.c, eventually invoked from MPI_Cancel > in my scenario: > > *static* *int* *mca_pml_ob1_send_request_cancel*(*struct* ompi_request_t* > request, *int* complete) > { > /* we dont cancel send requests by now */ > *return* OMPI_SUCCESS; > } > > The man page for MPI_Cancel does not mention that cancelling Send requests > does not work, so I’m wondering, > whether this is a current limitation or are we not supposed to end up in > this specific …_request_cancel implementation? > > Thank you in advance! > > Christian > -- Jeff Hammond jeff.scie...@gmail.com http://jeffhammond.github.io/
