Newsgroups: comp.parallel.pvm From: schaller@lrz-muenchen.de (Christian Schaller) Subject: ORNL PVM with SP2MPI? Keywords: ornl sp2mpi Organization: Leibniz-Rechenzentrum, Muenchen (Germany) Date: 12 Dec 1997 12:08:44 GMT Message-ID: <66r9gc$rh4$1@sparcserver.lrz-muenchen.de> RNL PVM on a IBM SP2 with SP2MPI? --------------------------------- For about 6 weeks we have severe problems with pvme on our IBM SP2. To have a good alternative to PVMe I tried to use the SP2MPI flavor of public domain PVM. I did not find very much documents about PVM/SP2MPI, so maybe someone out there has some experience with this port or can give me a link to some documentation. In my understanding communication in PVM/SP2MPI is faster than PVM/RS6K only for two tasks which are spawned within one call of pvm_spawn. Communicaton between tasks who were not spawned together, e.g. master to slave, remains slow because it has to pass the demon and therefore uses sockets. I tried to measure the performance in the different modes, i.e. I wrote a program with a master and two slaves which are spawned within one call of pvm_spawn. I measured the communication bandwith between the two slaves and between master and slave. In both cases the performance was about 2 MB/s which is not what I expected for slave to slave communication. Has anyone out there an idea? What could be the problem? How can I track the problem down? Any help is welcome Best regards Christian Schaller PS: I linked the master program with libpvm and the slave programs with libpvmpe and the mpxlf command. The slave program is a poe program! ,,, (o o) +----------oOO--(_)--OOo------------------------------+ | Christian Schaller email: schaller@lrz.de | | Leibniz-Rechenzentrum phone: +49-89-289-28825 | | Barer Str. 21 fax: +49-89-2809460 | | 80333 Munich | | Germany | +-----------------------------------------------------+ | http://www.lrz.de/persons/christian_schaller.html | +-----------------------------------------------------+