From: lindahl@pbm.com (Greg Lindahl)
Newsgroups: comp.parallel.mpi
Subject: Re: Speed using MPI
Date: 22 Sep 1998 01:01:43 GMT
Organization: a guest of Shadow Island Games
Message-Id: <6u6stn$5mq@news1.newsguy.com>
References: <6u64r3$9a5$1@news1.tc.umn.edu>


"AJ Lewis" <lewi0235@umn.edu> writes:

> I've been running some benchmark code to see what kind of performance I get
> with MPI vs. coding straight sockets.  I'm just sending a big array of
> doubles to another computer... and it seems that the max bandswidth I can
> get using MPI is approx 9MB/s as opposed to 12.4MB/s with sockets.

As someone else mentioned, it could be the extra data copies that are
hurting you here. However, if your program overlaps communication with
computaion, your benchmark isn't the right one, and those extra
copies might get you higher overall performance.

-- g