Also +1. On Jan 13, 2012, at 11:00 AM, George Bosilca wrote:
> Chris, > > If the sys call are there we should clearly take advantage of them. The patch > looks good, I vote for it! > > george. > > On Jan 12, 2012, at 04:34 , Christopher Yeoh wrote: > >> Hi Brad, >> >> WHAT: Adds Cross Memory Attach support to the sm btl >> >> WHY: For faster intranode communication >> >> WHERE: ompi/mca/btl/sm/ >> >> WHEN: Open MPI trunk >> >> TIMEOUT: 13/2/2012 >> >> Cross Memory Attach (CMA) is a pair of new syscalls (process_vm_readv >> and process_vm_writev) which allow for fast intranode >> communication. It has added to the Linux 3.2 kernel. There is a man page >> for the new system calls here: >> >> http://ozlabs.org/~cyeoh/cma/process_vm_readv.txt >> >> Attached is a patch for the OMPI trunk tree which augments the sm btl >> to use these calls. >> >> - CMA is quite similar in many respects to KNEM and what I've done is to >> pretty much copy what KNEM does in many cases. >> >> - Both KNEM and CMA can be compiled in at the same time, though if >> both are enabled at runtime, only KNEM runs. To enable CMA use >> --mca btl_sm_use_cma 1 >> >> - To enable CMA at compile time, add --with-cma=yes to the configure >> command line. Support for the syscalls is in the git glibc archive, >> but its not yet out in the distros so as an interim >> workaround I have added some arch/os specific wrappers which are used >> if the syscalls are not found at configure time. The syscalls numbers >> won't change as 3.2 is out. >> >> - I'm far from sure that the way I have used CMA in OMPI is the best >> way to do it, so any feedback is very welcome. >> >> Regards, >> >> Chris >> -- >> cy...@au.ibm.com >> >> >> <cma-openmpi-v1.patch>_______________________________________________ >> 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/
