[Beowulf] Gigabit Ethernet and RDMA

[Chris Samuel]

----- "Robert Kubrick" <robertkubrick at gmail.com> wrote:

> However, some observers predict TOE cards will be back as 10 Gigabit 
> Ethernet network capacity leapfrogs processing power again.

Van Jacobsen's "channelised" mods to the Linux TCP stack
described at Linux.Conf.Au in Dunedin, NZ in 2006 showed
that the 4.3Gb/s limit he hit on 10GigE was due to the
DDR333 MHz RAM in the box and not the CPUs, he commented
during the presentation that they'd proved it to themselves by
putting in faster memory and getting a speedup. :-)

http://www.lemis.com/grog/Documentation/vj/lca06vj.pdf

He estimated that you would need at least DDR800 RAM to
be able to have enough memory bandwidth to drive 10GigE
at capacity.

Whilst VJ's code didn't (to my knowledge) get published
it did inspire other work by kernel hackers, though I'm
not sure how much of it (if any) got into the mainline.

http://lwn.net/Articles/182060/

cheers,
Chris
-- 
Christopher Samuel - (03) 9925 4751 - Systems Manager
 The Victorian Partnership for Advanced Computing
 P.O. Box 201, Carlton South, VIC 3053, Australia
VPAC is a not-for-profit Registered Research Agency