Re: Minutes from Feb 21 LSE Call

From: Andy Pfiffer (andyp@osdl.org)
Date: Mon Feb 24 2003 - 13:36:55 EST


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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