On Sun, May 6, 2012 at 11:07 AM, Barry Smith <bsmith at mcs.anl.gov> wrote:
> Is your specific questions is: should we replace all MPI_Init() calls in > PETSc with MPI_Init_thread(...,MPI_THREAD_FUNNELED,...)? > Can't do this because of MPI-1 compatibility, but yeah, I'm thinking of always using MPI_THREAD_FUNNELED if configure picks it up. > > Will there be a performance hit, when one is not using threads? Should we > #if defined() do the replacement if the user has turned on OpenMP or > Pthread or TBB only and not by default? > Sounds like there is not likely to be a performance hit because the standard system routines are thread safe. http://lists.mcs.anl.gov/pipermail/mpich-discuss/2012-May/012380.html MPICH2 does not use POSIX functions like getchar_unlocked() or non-POSIX stuff like fwrite_unlocked(), so it seems like the library will be doing exactly the same thing in both cases. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-dev/attachments/20120506/2deac2a9/attachment.html>
