Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753065AbZGZDeF (ORCPT ); Sat, 25 Jul 2009 23:34:05 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753044AbZGZDeE (ORCPT ); Sat, 25 Jul 2009 23:34:04 -0400 Received: from mail-yx0-f198.google.com ([209.85.210.198]:34518 "EHLO mail-yx0-f198.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752972AbZGZDeD convert rfc822-to-8bit (ORCPT ); Sat, 25 Jul 2009 23:34:03 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=qCbA4uCmdMt4UC4E0c1Dof5/WcTCMDy4+VUrUHE2TMlyEwkko0+nIs4JTslXwaIp2V 3Hpbn2bPyF8CeZ3CnyujlzBQ0IxNHbB3j0zYdsUzas+7hPAhUVzc1a8dGCVkYEncY51h R7g+8HsBvcNflP+zosHRbsd4/V1v2SPaWShtg= MIME-Version: 1.0 In-Reply-To: <458a17f90907240745m15c3d7ep893a01a035bf0146@mail.gmail.com> References: <458a17f90907240745m15c3d7ep893a01a035bf0146@mail.gmail.com> Date: Sun, 26 Jul 2009 11:34:02 +0800 Message-ID: <2f495dc80907252034i4bdd812cx2267d65af7d993d8@mail.gmail.com> Subject: Re: inaccurate cpu idle time from top command From: Fred Fan To: cocala Cc: linux-arm-kernel@lists.arm.linux.org.uk, rick.jones2@hp.com, gallatin@myri.com, akpm@linux-foundation.org, dada1@cosmosbay.com, schwidefsky@de.ibm.com, brice@myri.com, paulus@samba.org, benh@kernel.crashing.org, mingo@elte.hu, gregkh@suse.de, linux-kernel@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1498 Lines: 35 Hi cocala: I have met same issue. And we found the total utilization count(added by idle's utilization) is not 100% in detail processes information fields. best Regards Fred 2009/7/24 cocala : > I saw one commit "3209ada8285a9fa6ab8f7a731d54031ec884c745 - sched: account > system time properly" > This commit is to take into account timer IRQ interrupting the idle task > servicing a hard or soft irq. > > If a softirq is started in a tick, all the time in the tick will be counted > as soft irq time even most time in the tick is idle. > In our use case, one jiffy is 10ms and the 1G net driver will generate many > software irq, so the "top" command will show high softare irq time and cpu > idle time approaches to zero. > If I change the jiffy to 1ms, the "top" command shows much higher cpu idle > time. I think this algorithm is also not fair for some cases. > > Is there any better way to count the softare irq time? > > Thanks > cocala > ------------------------------------------------------------------- > List admin: http://lists.arm.linux.org.uk/mailman/listinfo/linux-arm-kernel > FAQ: ? ? ? ?http://www.arm.linux.org.uk/mailinglists/faq.php > Etiquette: ?http://www.arm.linux.org.uk/mailinglists/etiquette.php > -- 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/