From: Vincent Nikkelen <vincentn@stack.nl>
Newsgroups: comp.parallel.pvm
Subject: Re: message size
Date: 1 Jul 1999 01:32:51 +0200
Organization: M.C.G.V. Stack - Eindhoven, the Netherlands
Sender: vincentn@turtle.stack.nl
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References: <Pine.HPP.3.95.990629111922.25921B-100000@horizon.radionics.com>
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Darren Porras <dporras@radionics.com> wrote:

: Hello all!

: I have a couple of questions regarding message size.

: 1) How does the cache play a role in determining the optimium message
: size. How does this role differ between a shared memory machine versus
: a cluster?

This depends on the kind of machine you are using. Mostly there is a
daemon running between PVM and your system, like PARSEC on a
PowerXplorer.

I have no experience with real shared-memory machines, but I guess PVM
is just passing pointers the way it is described in the documentation
you can find on netlib.org.

: 2) What is the best way to set message sizes in order to reduce PVM
: (memory) latency for packing/unpacking?

Test and measure. Guess thats the only answer one can give.

: Thanks in advance,
: Darren

Vincent