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Date:	Sat, 18 Sep 2010 06:32:48 -0500
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Subject:	Re: Unacceptable behavior -- slowing down script execution
From:	mike marchywka <marchywka AT gmail DOT com>
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On 9/17/10, SJ Wright <sjwright68 charter.net> wrote:
>
> 4. Is it normal for any script to run CPU usage up to 100%?

Unless it is blocking for something like IO including VM swaps, why not?


>
> Regarding #4:
> I have a script that I ran in GNOME Terminal less than an hour ago. I
> "time"d it -- the return was 20.6 seconds on the first line (real?). I
> ran the same script fifteen minutes later, evaluating identical files of
> the same type, length (5.37kb and 345b ASCII text) and time stamp, and
> after 7 minutes it was barely one-eighth complete. That's when I checked
> Task Manager and found my CPU usage was at 100% and three bash.exe's
> were running simultaneously. Admittedly the script calls on several

This sounds like a threading problem if I had to guess but it could
be anything that changed between runs- certainly timing will make
these things come and go but having no idea what you mean by identical
instead of  "the same" there are a lot of things that could have changed etc.
What did it seem to be trying to do? Often in cases like this
the alarming situation is where your cpu usage drops to low values
and your disk light gets stuck on as you have depleted memory.

I guess I'm also not sure what you think a usual or good number
of processes should be etc. A number of anecdotes have been
reported about slower performance on 64 bit or multi core machines
than  more primitive older cmoputers and it is easy to
speculate on reasons why that could happen
but hard to make a clear diagnosis without an explicit test case.

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