[Beowulf] Nehalem and Shanghai code performance for our rzf example

Joe Landman landman at scalableinformatics.com
Sat Jan 17 10:16:28 PST 2009

Kevin Abbey wrote:
> Hi Joe,
> Can that 9% difference be due to the Intel capability to overclock one 
> core and turn the others off?

Hi Kevin:

   Not sure.  May investigate at some point, but we should see a marked 
decrease in speedup over 4 threads on 4 cores if this is the case.

> Or is does this Intel feature require manual switch somewhere?

   No 'switches'.  Pure gcc, using -O3 flag, nothing "funky" in the code.


Joseph Landman, Ph.D
Founder and CEO
Scalable Informatics LLC,
email: landman at scalableinformatics.com
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