Newsgroups: comp.parallel.pvm,comp.parallel.mpi
From: heagy@cs.vt.edu (Winfield S. Heagy)
Subject: Re: PVMe/MPI comparison on SP2
Organization: Virginia Tech, Blacksburg, Virginia
Date: 16 Apr 1996 19:23:34 GMT
Message-ID: <4l0s3m$9il@server.cs.vt.edu>

Graham E Fagg (fagg@cs.utk.edu) wrote:
: I'm sorry that I don't have access to a PVMe setup at the moment to 
: verify what you are claiming, but:
: When claiming system A is better than system B, please give us the 
: conditions of your experiment (configurations used). If the two systems 
: are being used in a similar way (e.g. buffered verses non-blocking 
: direct) and the actual method used such as ping-pong, head to head or via a 
: known benchmarking system.

: A few results would also help, as it might be the case that a small 
: oversight in the test has drastically effected the results.. without 
: values we don't know how 'bad' a particular system appears to you.

: I work as part of the PVM team here at UTK and not for IBM, so I'm not 
: defending their implementation, but without specific details we cannot 
: give you specific answers,

: thanks,
:                                                                    O__
: Graham.                                                            ,>/

We did a 2^6 experiment where the factors were message library,
message type, message size, encoding, switch, and type receive.
This required 64 programs that had unique combinations of these
factors.  The levels were MPI-PVM, Integer-String, 60 bytes-
6000 bytes, XDR-RAW, ethernet-HPS, blocking-nonblocking, respectively.
The message was passed 100 times in each program.  We have
since come to learn that ethernet should not be used on the SP2
and that it will default to HPS, so our experiment size will be
reduced to 32.

We are going to rerun the experiment, so results will be available
in a week or two.  However, if you can provide any insight based
on the experiment design, it would be appreciated.

Thanks, 
Win

--
--------------------------------------------------------------------------
|| //////// V I R G I N I A    T E C H    C O M P U T E R    S C I E N C E
||//  //                       W i n   H e a g y
|//  //     heagy@csgrad.cs.vt.edu   http://csgrad.cs.vt.edu/~heagy/
--------------------------------------------------------------------------

