Date: Wed, 27 Aug 2008 14:20:06 GMT From: Kris Kennaway <kris@FreeBSD.org> To: freebsd-bugs@FreeBSD.org Subject: Re: kern/126880: CPU usages are unbalanced Message-ID: <200808271420.m7REK6K6036934@freefall.freebsd.org>
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The following reply was made to PR kern/126880; it has been noted by GNATS.
From: Kris Kennaway <kris@FreeBSD.org>
To: KOIE Hidetaka <koie@suri.co.jp>
Cc: freebsd-gnats-submit@FreeBSD.org
Subject: Re: kern/126880: CPU usages are unbalanced
Date: Wed, 27 Aug 2008 16:14:15 +0200
KOIE Hidetaka wrote:
> Idle times per CPU can be watched by top(1).
> But these times are clearly different.
>
>> How-To-Repeat:
> This machine is dual-core opteron and dual-socket.
> koie@guriandgura% top -HSn|grep idle
> 11 root 171 ki31 0K 64K RUN 0 26.7H 41.55% {idle: cpu0}
> 11 root 171 ki31 0K 64K RUN 2 23.5H 31.88% {idle: cpu2}
> 11 root 171 ki31 0K 64K RUN 1 19.9H 15.19% {idle: cpu1}
> 11 root 171 ki31 0K 64K RUN 3 20.8H 9.18% {idle: cpu3}
Do you have evidence that this is causing a performance problem? Your
system is not 100% busy anyway, and it is often better to keep a
long-running task running on the same CPU where it can benefit from hot
caches rather than bouncing it around between CPUs where it will suffer
from lots of cache misses.
Kris
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