From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753619Ab0JVBhi (ORCPT ); Thu, 21 Oct 2010 21:37:38 -0400 Received: from mail-gx0-f174.google.com ([209.85.161.174]:42482 "EHLO mail-gx0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751416Ab0JVBhh (ORCPT ); Thu, 21 Oct 2010 21:37:37 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=wQH5t6CQmDuCDlgjRMTTPDfl4tF2vzeuFISr65x/ZDONXYxcPyQ63YD+dzheq2uEDi KQVcvBsLKSi+uyvp//CAwlEmuAB8pS2WR6OFepnmNbp1lgRASOP4IEWNv972qNnqUjaz 3uq48xmpYhl66cjWd/qigKHTMhiQ2mwMTJxeg= Date: Thu, 21 Oct 2010 21:37:32 -0400 From: tmhikaru@gmail.com To: Peter Zijlstra , Damien Wyart , Chase Douglas , Ingo Molnar , Thomas Gleixner , linux-kernel@vger.kernel.org, Venkatesh Pallipadi Subject: Re: High CPU load when machine is idle (related to PROBLEM: Unusually high load average when idle in 2.6.35, 2.6.35.1 and later) Message-ID: <20101022013732.GA6652@roll> References: <20100929070153.GA2200@brouette> <20101014145813.GA2185@brouette> <20101020132732.GA30024@brouette> <1287581440.3488.16.camel@twins> <1287582208.3488.20.camel@twins> <1287584073.3488.22.camel@twins> <1287595605.3488.52.camel@twins> <20101021014843.GA21295@roll> <20101021183621.GA2244@roll> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="KsGdsel6WgEHnImy" Content-Disposition: inline In-Reply-To: <20101021183621.GA2244@roll> User-Agent: Mutt/1.4.2.3i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --KsGdsel6WgEHnImy Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Oct 21, 2010 at 02:36:21PM -0400, tm@ wrote: > On Wed, Oct 20, 2010 at 09:48:43PM -0400, tm@ wrote: > > On Wed, Oct 20, 2010 at 07:26:45PM +0200, Peter Zijlstra wrote: > > >=20 > > >=20 > > > OK, how does this work for people? I find my idle load is still a tad > > > high, but maybe I'm not patient enough. > >=20 > > I haven't had a chance to keep up with the topic, and I apologize. I'll= be > > testing this as soon as I can finish compiling it. Thank you all for not > > letting this go unfixed. > >=20 > > Tim McGrath >=20 > Now that I've actually had a chance to boot the kernel with the patch > applied I'm sorry to say but the load average isn't decaying as fast as it > ought to, at the very least. My machine's been idle for the last ten minu= tes > but the one minute average is still at 0.89 and shooting up to 1.5, the 5 > min average is 0.9, and the 15 min average is .68 and climbing. Even as I= 'm > writing this the averages are continuing to drop, but *very* slowly. > Glacially, almost. The one minute average is continuing to randomly spike > high for no reason I can tell as well. >=20 > I'll let you guys know if this actually bottoms out at some point. >=20 > Tim McGrath It did not. When I came home and checked, my load average was a steady 0.7-0.8 across the board on all averages with the machine idle since six hours ago. I guess the patch didn't fix the problem for me. If you want, I'll try building master/tip with the patch applied, but I doubt it'll really be different. On the plus side, the patch did do something - it seems much less erratic than it used to be for whatever reason, and now just has a very steady load average rather than jumping about as it does without the patch applied. I wish I understood the code enough to know what is going wrong here. I have to wonder what impact the original bug was causing. It seems to me that if it only affected a few people it might be worth backing out the patch and rethinking the problem it was meant to fix. On the other hand, if there's some way of diagnosing the problem I'm all for it - is there some kprintfs or something I could put in the code to find out when it's doing unlikely or 'impossible' things? There is serious weirdness going on here and I'd like to figure out the cause of it. I get the impression we're all bumbling about in the dark poking at a gigantic elephant and getting the wrong impressions. Tim McGrath --KsGdsel6WgEHnImy Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) iQEVAwUBTMDq3JEncCrqzVruAQIYoAf/YafY4vG2vszmP6Zan8a8vQVSIp8C4wp2 4648znjze6W7n/R7lh5tMUCAIjI3P0gbMrlQJAKUQcbgdw6BtMER0V482U29S+Te AgqBuqWtm3AbfYCGpSPQzenFBEizjdHKfVG+jcz02OqNh4igducZUhWBi66cm6BG JMtJD5zH654LYsqGQzRYcRTja8TY5LrU80uahbOoLJm0fSsEn40B6Decgvkv7r+U qOOyzoAeF2y6Dn/A94SpBsaP8MCJiu0zhw3avYspXtI3/XdHXPnV+bpkpCrpCvhI Ukyh4HLDeKv7i8FvbxrRSv+4j7mBF1Z2KvnHsv+pWH9+BHvpFIhuuQ== =CiM/ -----END PGP SIGNATURE----- --KsGdsel6WgEHnImy--