Re: [info-performer] Jitter behavior

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From: lawrence bertoldi (lberto++at++md.prestige.net)
Date: 07/10/2002 11:07:58


CPU 0 handles all the system level stuff like interrupts and I/O. is
there a possibility that your
waiting on IO for your app?

Chris Sandridge wrote:

> We have a pfCAVE application that exhibits sub-par performance on a
> 16-processor, 4-IR2 pipe, Onxy2 when other jobs are running on CPU 0.
> We have observed, via top, that when long-running processes are
> running near 100% on CPU 0, we get jitter in any movement in our
> pfCAVE application - instead of smooth rotations, translations, we get
> rapid starts and stops. But when the job on CPU 0 is finished, the
> jitter goes away. Jobs running on all CPUs other than 0 have no
> affect on the pfCAVE application.
>
> Is there something in Performer that needs CPU 0 and is there anyway
> to prevent other processes from interrupting that need. We still
> haven't determined exactly what causes the jitter, just that the load
> on CPU 0 seems to have a connection. Any ideas?
>
> Thanks,
> Chris
> ___________________________________________________________________
> Chris A. Sandridge
> Immersive Design and Simulation Lab
> Analytical and Computational Methods Branch
> M.S. 240, NASA Langley Research Center
> 3 Langley Blvd., B1229, Rm. 237
> Hampton, VA 23681
> email: c.a.sandridge++at++larc.nasa.gov
> phone: (757) 864-2816
> fax: (757) 864-8912
>
>


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