From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 9 Aug 2001 20:36:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 9 Aug 2001 20:36:44 -0400 Received: from harpo.it.uu.se ([130.238.12.34]:52734 "EHLO harpo.it.uu.se") by vger.kernel.org with ESMTP id ; Thu, 9 Aug 2001 20:36:41 -0400 Date: Fri, 10 Aug 2001 02:36:50 +0200 (MET DST) From: Mikael Pettersson Message-Id: <200108100036.CAA09153@harpo.it.uu.se> To: linux-kernel@vger.kernel.org, safemode@speakeasy.net Subject: Re: kapm-idled shows 90+% cpu usage when idle Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 9 Aug 2001 19:33:42 -0400, safemode 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