[AG-DEV] why is CPU Affinity restricted to the first processor?
Robert Olson
olson at mcs.anl.gov
Mon Mar 19 12:21:04 CDT 2007
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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