From: Mikael Pettersson <mikpe@csd.uu.se>
To: linux-kernel@vger.kernel.org, safemode@speakeasy.net
Subject: Re: kapm-idled shows 90+% cpu usage when idle
Date: Fri, 10 Aug 2001 02:36:50 +0200 (MET DST) [thread overview]
Message-ID: <200108100036.CAA09153@harpo.it.uu.se> (raw)
On Thu, 9 Aug 2001 19:33:42 -0400, safemode <safemode@speakeasy.net> wrote:
>Is this a true usage reading or just some quirk that's supposed to happen?
>I really doubt that this kernel daemon should really be using cpu. It seems
>to respond with a higher cpu usage when i'm idle. It immediately goes away
>when something else uses cpu. If you need any more info just ask. I'm
Do you have CONFIG_APM_CPU_IDLE=y in your .config? If so, disable it.
There was a thread about this problem some months ago. I found
that on all of my APM-capable machines, including a Dell laptop,
CONFIG_APM_CPU_IDLE=y had a negative effect. The kernel ended up
in a tight loop performing tons of APM IDLE BIOS calls, since each
BIOS call returned immediately without having idled the CPU.
Leaving CONFIG_APM_CPU_IDLE unset lets the kernel use its own
"HLT when idle" code. On my main development box, idle CPU
temperature dropped >10 degrees C, and kapm-idled now uses 0% CPU.
/Mikael
next reply other threads:[~2001-08-10 0:36 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-08-10 0:36 Mikael Pettersson [this message]
2001-08-10 2:01 ` kapm-idled shows 90+% cpu usage when idle safemode
2001-08-10 17:36 ` Mike Fedyk
-- strict thread matches above, loose matches on Subject: below --
2001-08-09 23:33 safemode
2001-08-10 19:44 ` Erik Mouw
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