Newsgroups: comp.parallel
From: mtaylor@easynet.com (Michael A. Taylor)
Subject: Re: Help - explain superlinear speedup?
Organization: InterNex Information Services, Inc.
Date: Fri, 13 Jan 1995 15:58:03 GMT
Message-ID: <mtaylor-1201952012570001@192.0.2.1>

In article <3f23ht$ec9@agate.berkeley.edu>, slater@nuc.berkeley.edu (Steve
Slater) wrote:


> With p4, I first run 4 processes (4 regions) on only 1 machine.
> The messages are passing through sockets. Then I run
> on 2 machines, each having 2 processes (2 regions), and
> finally on 4 machines, each having 1 process (region).
> 
> 

You are reducing the number of process switches and also the cache
flushing that occurs with each process switch.

Therefore you are executing fewer instructions (less switches) and they
execute faster (fewer cache faults).


