Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 30 Nov 2001 07:37:01 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 30 Nov 2001 07:36:51 -0500 Received: from hermes.domdv.de ([193.102.202.1]:38928 "EHLO zeus.domdv.de") by vger.kernel.org with ESMTP id ; Fri, 30 Nov 2001 07:36:39 -0500 Message-ID: X-Mailer: XFMail 1.5.1 on Linux X-Priority: 3 (Normal) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit MIME-Version: 1.0 In-Reply-To: Date: Fri, 30 Nov 2001 13:34:03 +0100 (CET) Organization: D.O.M. Datenverarbeitung GmbH From: Andreas Steinmetz To: Alan Cox Subject: Re: kapm-idled no longer idling CPU? Cc: linux-kernel@vger.kernel.org, Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On 30-Nov-2001 Alan Cox wrote: >> application that uses more than very minor system resources is running, >> (i.e. mozilla, netscape, xemacs, apache, Tomcat, just to name a few >> common ones I've seen this behaviour with) kapm-idled no longer receives >> scheduling time from what I can tell and I assume that means my CPU is >> never getting idled when nothing is scheduled. > > kapm_idled will get scheduling time when there is nothing else to run, > whether it wants it or is using it is more of the question. > Well, that's exactly the problem. in apm_mainloop the following happens: timeout = 2 * timeout; if (timeout > APM_CHECK_TIMEOUT) timeout = APM_CHECK_TIMEOUT; schedule_timeout(timeout); ... if (!system_idle()) continue; ... if (apm_do_idle() != -1) { ... timeout = 1; } This just means that after a busy condition we start at 1 and increase the scheduling delay until the timeout reaches HZ. system_idle itself just checks, if nr_running is 1. This means that if any single other process is runnable every HZ time when apm_idled checks the system state it won't switch to idle state even if the system is otherwise idle. I do see this behaviour e.g. all the time with KDE. Just create a process that does a select timeout every HZ and down the drain goes your laptop battery, when the select call meets kapm-idled polling time. Andreas Steinmetz D.O.M. Datenverarbeitung GmbH - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/