[Beowulf] Re: More cores/More processors/More nodes?

[Håkon Bugge]

Depends on what you're asking.

The benefit of running two times two processes 
per node probably stems from the fact that 
applications usage of interconnect is temporal in 
time. Hence, by running two application instances 
per node, the interconnect usage is more spread in time.

The benefit of different policies of the 
process-to-processor binding depends on more 
issues. YMMV application wise. Further, some 
multicore processor have a shared cache between 
the cores (Woodcrest). Communication intensive 
apps might then benefit from this cache. Other 
apps tend to like running on two Opterons to get 
the luxery of (mostly) using two memory controllers. And others don't.

Håkon

At 23:15 05.10.2006, Mark Hahn wrote:
>>On two-socket, dual core Opteron systems, we 
>>often see that throughput is enhanced by using 
>>two times two processes per node.
>
>just for the obvious reason?  (memory bandwidth)

--
Håkon Bugge
CTO
dir. +47 22 62 89 72
mob. +47 92 48 45 14
fax. +47 22 62 89 51
Hakon.Bugge at scali.com
Skype: hakon_bugge

Scali - http://www.scali.com
Scaling the Linux Datacenter