Newsgroups: comp.parallel.mpi
From: salo@cray.com (Eric Salo)
Subject: Re: persistant communication & O2k
Organization: Silicon Graphics, Inc.
Date: 25 May 1997 01:04:47 GMT
Message-ID: <5m837f$1h1$1@walter.cray.com>

> 1) shall i save any time by using MPI_start

This is very implementation dependent. The common wisdom is that
persistent sends and recvs are supposed to be faster, but I know
of several implementations for which this opposite is true.

You didn't mention which MPI implementation you are using on your
O2K, but if it's the SGI MPI 2.0 release then persistent requests
are slightly faster than non-persistent requests, and if it's a
beta release of our MPI 3.0 then the persistent requests are
slightly slower.

--
Eric Salo      Silicon Graphics      salo@sgi.com