On Apr 24, 2012, at 4:24 PM, William Gropp wrote:

Yes, an MPI process need not be an OS process, and there is in fact a long history of such implementations, starting (as far as I know) with TMPI. An easy out is to make this optional and only apply when there is such a one-to-one mapping of MPI and OS processes.

That would defeat the use-case that I proposed (tools needing a unique ID for the process). Other options: - provide a comma-delimited list of MCW ranks in the OS process - provide the lowest (or highest? or median? or ...?) MCW rank in the OS process - ...some other unique value Any kind of unique value would allow the tool to have a unique, safe filename. The MPI (or runtime) is in a good position to provide this unique value because it has global knowledge of the entire MPI job, where the tool does/may not. -- Jeff Squyres [email protected] For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/