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Subject: Re: Minutes from Feb 21 LSE Call
From: Andy Pfiffer <andyp@osdl.org>
To: Larry McVoy <lm@bitmover.com>
Cc: William Lee Irwin III <wli@holomorphy.com>,
       Mark Hahn <hahn@physics.mcmaster.ca>,
       "Martin J. Bligh" <mbligh@aracnet.com>, linux-kernel@vger.kernel.org
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On Sat, 2003-02-22 at 15:28, Larry McVoy wrote:
> On Sat, Feb 22, 2003 at 02:17:39PM -0800, William Lee Irwin III wrote:
> > On Sat, Feb 22, 2003 at 05:06:27PM -0500, Mark Hahn wrote:
> > > ccNUMA worst-case latencies are not much different from decent 
> > > cluster (message-passing) latencies.
> > 
> > Not even close, by several orders of magnitude.
> 
> Err, I think you're wrong.  It's been a long time since I looked, but I'm
> pretty sure myrinet had single digit microseconds.  Yup, google rocks,
> 7.6 usecs, user to user.  Last I checked, Sequents worst case was around
> there, right?

FYI: The Intel/DOE ASCI Red system (>1 TFLOPS) delivered user-to-user
messaging of < 5us.  With a tail wind, peak point-to-point data rates,
delivered from a user-mode buffer into another user-mode buffer anywhere
else on the system were just shy of 400 megabytes/second (actual rates
could be affected by several factors -- obviously).


Andy


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