On May 19, 2011, at 9:46 PM, Larry Baker wrote: > I inquired the same of PGI. Dave Borer, PGI Customer Service Manager, > responded: > >> I believe -fast and -fastsse are identical for 64-bit compilers, but there >> are some differences >> with 32-bit compilers. I don't think TCP/IP based MPI routines have better >> performance from >> optimizations, unless the processes are all running on the same machine. I >> will ask engineering >> how messages are passed when all the processes are running on the same >> hardware.
Ya -- he's pretty much right. When the procs are on the same machine, we end up memcpy'ing through shared memory. Hence, if the memcpy is sped up by using -fast or -fastsse, that would be your extra bonus points. :-) -- Jeff Squyres jsquy...@cisco.com For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/
