Jeff Hammond <jeff.scie...@gmail.com> writes: >> >> >> > Note that MPI implementations may be interested in taking advantage of >> > https://software.intel.com/en-us/blogs/2016/10/06/intel- >> xeon-phi-product-family-x200-knl-user-mode-ring-3-monitor-and-mwait. >> >> Is that really useful if it's KNL-specific and MSR-based, with a setup >> that implementations couldn't assume? >> >> > Why wouldn't it be useful in the context of a parallel runtime system like > MPI? MPI implementations take advantage of all sorts of stuff that needs > to be queried with configuration, during compilation or at runtime.
I probably should have said "useful in practice". The difference from other things I can think of is that access to MSRs is privileged, and it's not clear to me what the implications are of changing it or to what extent you can assume people will. > TSX requires that one check the CPUID bits for it, and plenty of folks are > happily using MSRs (e.g. > http://www.brendangregg.com/blog/2014-09-15/the-msrs-of-ec2.html). Yes, as root, and there are N different systems to at least provide unprivileged read access on HPC systems, but that's a bit different, I think. _______________________________________________ users mailing list users@lists.open-mpi.org https://rfd.newmexicoconsortium.org/mailman/listinfo/users
