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Date: Thu, 12 Nov 2009 08:42:28 -0800
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Thread-Topic: 8.0RC2 "top" statistics seem broken
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References: <hdc0sp$br4$1@ger.gmane.org> <20091112071618.GB81250@rambler-co.ru>
From: "Matthew Fleming" <matthew.fleming@isilon.com>
To: "Igor Sysoev" <is@rambler-co.ru>,
	<freebsd-stable@freebsd.org>
Cc: 
Subject: RE: 8.0RC2 "top" statistics seem broken
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> > [snip]
> >=20
> > Load average and %CPU user are right, as are other global
statistics.
> > The load is produced by the "7z" process (archivers/p7zip) which
> > compresses some data in two threads but is credited with 0% CPU,
though
> > its runtime is correct (increments every second as it should in a
> > CPU-bound process). It doesn't help if I expand / show individual
> threads.
>=20
> I believe this is related to multithreaded processes only. I saw this
for
> intr kernel process. Singlethread processes eat CPU slightly less than
> on 7.2, however, I can not say is it statistic errors or real speedup.
> I saw the issue on SMP/ULE only and can not say anything about UP and
> 4BSD scheduler.

Check out r197652 on stable/7.  I had a similar problem where top was
showing 0% for a CPU hog, but since I was unable to replicate it on
CURRENT (and the ULE accounting code is different between releases) I
only submitted for stable/7.  I think the patch will be easy to apply by
hand, though, to test it.

Thanks,
matthew