[Insight-users] Speed

[Sean McBride]

On Wed, 9 Feb 2011 22:11:37 +0000, Matt McCormick said:

>> I'm intrigued by the way these ITK filters automatically utilize multiple 
>> processors, and I'm wondering if there is a way to set the number of
>threads 
>> that will be invoked.  No doubt there's an IJ article on this topic ..
>
>The default is to set the number of threads to the number of cores available 
>(pretty nice).

Actually, it's not all that nice, because with modern CPUs the number of
cores can change at runtime (cores turn off to save power).  Even
without that, there's no good way for any one program to know how many
cores it should use.  If every app decides it should use *all* cores,
then overall system performance suffers.  Interaction with the OS is
required, ideally by letting the OS decide.  For example:
<http://en.wikipedia.org/wiki/Grand_Central_Dispatch>

-- 
____________________________________________________________
Sean McBride, B. Eng                 sean at rogue-research.com
Rogue Research                        www.rogue-research.com 
Mac Software Developer              Montréal, Québec, Canada