Re: New Computer

[David Dunbar <ddunbar@geocenter.com>]

Chris Albertson wrote:
> Just got back from a couple weeks in Canada (Vancouver, BC)
> All bet a Pentium $, 3GHz with "hyperthreading" would be almost
> exactly as fast as your dual AMD system.

Depending on how compute intensive the job is, hyperthreading can be a 
booby trap. We have a 100 node Linux cluster of dual CPU 2.4 GHz 
machines for seismic migration and other compute intensive tasks. When 
delivered they had hyperthreading turned on. We normally send two 
threads to each cluster node. Jobs were very inconsistent in execution 
times. It turned out that the scheduler would randomly assign the jobs 
to the same CPU and let the other sit idle. We turned hyperthreading off.

David
-- 
David M. Dunbar <ddunbar@geocenter.com>
Unlike cockroaches, Windows NT is something you can't possibly be unfair to.
-Peter da Silva