12/17/2002, 17:28 - Need info !

[David Wan]

To whom it may concern/know :

As regarding "Myrinet has both a cost and increasing performance
advantage over gigabit Ethernet when the switch is larger than about
96 ports" .

Can you supply more detailed info !

TKS !

Regards,
David C. Wan
12/17/2002, 17:28

----- Original Message -----
From: "jon" <jcmcknny at uiuc.edu>
To: "'Donald Becker'" <becker at scyld.com>
Cc: <beowulf at beowulf.org>
Sent: Tuesday, December 17, 2002 2:12 PM
Subject: RE: low-latency high-bandwidth OS bypass user-level messaging for
commodity(linux) clusters with commodity NICs(<$200), HELP!
(GAMMA/EMP/M-VIA/etc.)


> > -----Original Message-----
> > From: Donald Becker [mailto:becker at scyld.com]
> > Sent: Monday, December 16, 2002 6:32 PM
> > To: jon
> > Cc: beowulf at beowulf.org
> > Subject: Re: low-latency high-bandwidth OS bypass user-level messaging
> for
> > commodity(linux) clusters with commodity NICs(<$200), HELP!
> (GAMMA/EMP/M-VIA/etc.)
> >
> > On Mon, 16 Dec 2002, jon wrote:
> >
> > > Perhaps this isn't the best way to get ahold of you, but I've also
> sent
> > > this to the Beowulf list.  I've noted your comments on OS Bypass
> drivers
> > > in the past.  But isn't there some room for non-TCP/IP related
> traffic,
> > > such as with computing clusters?  We don't need no stinking TCP!  No
> > > associated revenue?  You could replace Myrinet in the thousands of
> nodes
> > > we have here ALONE at NCSA.
> >
> > Very likely not.  Myrinet has both a cost and increasing performance
> > advantage over gigabit Ethernet when the switch is larger than about
> 96
> > ports.
>
> [jon] I see.
>
> >
> > > We (UIUC theoretical astrophysics group) are in the midst of
> purchasing
> > > a $50K cluster (I know, small, but big for us! :)) and I'm done all
> the
> > > research as to what we should be getting.  We ended up going with a
> > > Intel Desktop gigabit board and P4, but have found the tests to be
> very
> > > poor.  We only have 4 nodes right now because we worried about this
> very
> > > thing.
> >
> > Latency or bandwidth?  And what are you using to test?
>
> [jon] We need (projected 0 message size) latencies to be about 30-40us
> for our applications.  We end up with message sizes ranging from
> 256bytes to 8KB for different applications.  A 2.4Ghz P4 cluster has an
> idling CPU due to the latency.
>
> > While there are better Gigabit chips than the DP83820, most of its bad
> > reputation comes from the poor performance of the other drivers out
> > there.  We get quite reasonable performance from it with the Scyld
> > ns820.c driver.  Others have reported a 2.5-3X performance improvement
> > over the driver written by Red Hat.
>
> [jon] I see, what kinda of 0message latency and peak bandwidth do you
> get on 64-bit 66Mhz bus?
>
> [jon] Thanks! -Jon
>
>
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