[Beowulf] Home beowulf - NIC latencies

Andrew Piskorski atp at piskorski.com
Fri Feb 4 12:20:23 PST 2005

On Thu, Feb 03, 2005 at 04:53:27AM +0100, Vincent Diepeveen wrote:

> Please note MPI is probably what i'll use, though i keep finding
> online information about 'gamma'. Is that faster latency than MPI
> implementations?


Gamma is a non-TCP/IP Linux 2.6.x network driver for Intel Pro/1000
gigabit ethernet cards, for use with MPI.  It offers much better
latency (11 us or so) than TCP/IP over ethernet (maybe 60 or 100 us),
but worse than the specialized HPC interconnects (maybe 3 us).

The attraction of GAMMA, is that Intel Pro/1000 cards can be had for
$11 to $60 or so each (depending on exact model, etc.), and gigabit
switches are also pretty cheap, while SCI or Myrinet is somewhere in
the $500 to $1500 per node range (I don't keep track).

So if your application can benefit from lower latency, but you want
something really cheap, GAMMA should be well worth trying.

Andrew Piskorski <atp at piskorski.com>

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