----- Forwarded message from Joachim Worringen <[EMAIL PROTECTED]> -----
From: Joachim Worringen <[EMAIL PROTECTED]>
Date: Tue, 09 Nov 2004 22:54:35 -0500
To: [EMAIL PROTECTED]
Subject: Re: [Beowulf] torus versus (fat) tree topologies
Organization: NEC Europe Ltd. - C&C Research Lab
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US;
rv:1.7) Gecko/20040616
Greg Lindahl wrote:
>On Mon, Nov 08, 2004 at 11:45:12PM -0500, Chris Sideroff wrote:
>> I have had the luxury of testing an SCI 2D torus cluster and found
>>latency performance to be exceptional.
>
>Right. So is that a feature of the NIC, or a feature of the torus
>instead of a fat tree/CLOS/CBB network? Answer: the NIC.
Yes, a feature of the NIC, plus: the torus doesn't affect the latency
significantly. In fact, the cost of a hop in an SCI-based torus, like an
other reasonable modern torus, is only a low number of nanoseconds (I'd
have to look it up right now for an exact number which I can not do from
here; I think there's also such a number in a recent publication on
BlueGene). A hop in a router node has about the same delay (as it is has
a similar task).
Joachim
--
Joachim Worringen - NEC C&C research lab St.Augustin
fon +49-2241-9252.20 - fax .99 - http://www.ccrl-nece.de
_______________________________________________
Beowulf mailing list, [EMAIL PROTECTED]
To change your subscription (digest mode or unsubscribe) visit
http://www.beowulf.org/mailman/listinfo/beowulf
----- End forwarded message -----
--
Eugen* Leitl <a href="http://leitl.org";>leitl</a>
______________________________________________________________
ICBM: 48.07078, 11.61144 http://www.leitl.org
8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE
http://moleculardevices.org http://nanomachines.net
-------
To unsubscribe, change your address, or temporarily deactivate your
subscription,
please go to http://v2.listbox.com/member/[EMAIL PROTECTED]
pgpymR4jQKUyr.pgp
Description: PGP signature
