Date: Wed, 24 Nov 2010 09:40:13 GMT From: Andriy Gapon <avg@freebsd.org> To: freebsd-amd64@FreeBSD.org Subject: Re: amd64/152405: wrong user time is reported when CPU frequency throttled. Message-ID: <201011240940.oAO9eDCm021038@freefall.freebsd.org>
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The following reply was made to PR amd64/152405; it has been noted by GNATS.
From: Andriy Gapon <avg@freebsd.org>
To: =?ISO-2022-JP?B?IktPSUUgSGlkZXRha2EgKBskQjhxOT4xUU40IXc/dE19NTs4JhsoQg==?=
=?ISO-2022-JP?B?KSI=?= <koie@suri.co.jp>
Cc: bug-followup@freebsd.org
Subject: Re: amd64/152405: wrong user time is reported when CPU frequency
throttled.
Date: Wed, 24 Nov 2010 11:31:38 +0200
on 24/11/2010 09:17 KOIE Hidetaka ($B8q9>1QN4!w?tM}5;8&(B) said the following:
> % sudo sysctl kern.eventtimer.timer="i8254"
> Password:
> kern.eventtimer.timer: LAPIC -> i8254
> % sudo sysctl dev.cpu.0.freq=1800
> dev.cpu.0.freq: 1800 -> 1800
> % time ./loop
> ffffffff
> 0.000u 4.773s 0:00.08 5962.5% 0+0k 0+0io 0pf+0w
> % sudo sysctl dev.cpu.0.freq=1000
> dev.cpu.0.freq: 1800 -> 1000
> % time ./loop
> ffffffff
> 0.000u 4.773s 0:00.21 2271.4% 0+0k 0+0io 0pf+0w
> % sleep 1
> ("sleep" had returned after sysctl kern.eventtimer.timer="LAPIC" on another terminal)
> %
>
> NOTE: user time is 0, system time is too long, and elapsed time is too short.
>
> And, wall-clock has been slow...
> % ssh my-server date ; env LANG=C date
> Wed Nov 24 16:03:11 JST 2010
> Wed Nov 24 16:01:15 JST 2010
Can you try to boot with kern.eventtimer.timer="i8254" in loader.conf?
--
Andriy Gapon
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