Newsgroups: comp.parallel.mpi
From: Kevin Morooney <kxm@psu.edu>
Subject: Re: What is the software overhead of SP2?
Organization: Penn State University, Center for Academic Computing
Date: Fri, 07 Mar 1997 20:07:41 -0500
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Message-ID: <3320BBDD.167E@psu.edu>

Michael Pernice wrote:
> 
> Jinsheng Xu wrote:
> >
> > Hi,
> >
> > What is the software overhead of SP2 of short message? How can
> > we measure it?
> >
> > Thank you for you answer!
> >
> > J.
> 
> For the SP2 with the Power2 nodes it is about 40 microseconds.
> The usual way to determine it is to measure the times for messages
> of increasing sizes, then do a least squares fit of the result to
> the usual linear model t = t_o + n*t_b, where n is the number of
> bytes in the message.

I think that's for TB2 .  For TB3, latency should be below 20 
microseconds (bandwidth ~70MB/s). -Kevin
                               Penn State