[AG-DEV] why is CPU Affinity restricted to the first processor?

[Robert Olson]

IIRC there was an issue (some time ago) where letting vic bounce  
between processors on a multiple CPU box resulted in worse  
performance than binding it to a single CPU...

--bob

On Mar 19, 2007, at 12:05 PM, Ed Brannin wrote:

> Hello,
>
> I'm running a Dell "Pentium(R) D 3.46GHz" system with...  well, I'm  
> not sure if it has multiple CPUs or just Hyperthreading, but the  
> Task Manager shows 4 CPU usage graphs.
>
> Last week, we had some trouble with dropped packets -- and as it  
> turned out, it was partly because all the AG-related processes were  
> starving each other on CPU #0.  Manually enabling the CPU affinity  
> to use all CPUs for each pythonw, dvts, vlc, vic, etc. process  
> brought that problem under control, so I'm wondering: why does AG  
> restrict itself to one CPU under win32?
>
> I see this happens in AccessGrid/Platform/win32/Config.py:555-572,  
> and was added by Tom Uram in January 2006 -- but I haven't been  
> able to find any discussion of why with Google, the mailing list  
> search or Bugzilla.
>
> Would it be possible to spread processes across each CPU, or even  
> leave them with the default CPU affinity?
>
> -Ed Brannin
> edbrannin at gmail.com

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