From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932258Ab2DQMwl (ORCPT ); Tue, 17 Apr 2012 08:52:41 -0400 Received: from mail-wi0-f170.google.com ([209.85.212.170]:54289 "EHLO mail-wi0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932125Ab2DQMwk (ORCPT ); Tue, 17 Apr 2012 08:52:40 -0400 Message-ID: <4F8D678C.6050104@nasza-klasa.pl> Date: Tue, 17 Apr 2012 14:52:28 +0200 From: =?UTF-8?B?TGVzxYJhdyBLb3BlxIc=?= User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.28) Gecko/20120313 Lightning/1.0b2 Thunderbird/3.1.20 MIME-Version: 1.0 To: Peter Zijlstra CC: Aman Gupta , linux-kernel@vger.kernel.org, Chase Douglas , Damien Wyart , Kyle McMartin , Venkatesh Pallipadi , Jonathan Nieder , Doug Smythies , Thomas Gleixner Subject: Re: Inconsistent load average on tickless kernels References: <4F465F6E.9070605@nasza-klasa.pl> <1330517195.11248.148.camel@twins> <1330532667.11248.153.camel@twins> <1330534998.11248.158.camel@twins> <4F551ABE.5080605@nasza-klasa.pl> <1330989903.11248.261.camel@twins> <1330990360.11248.264.camel@twins> <1330990413.11248.265.camel@twins> In-Reply-To: <1330990413.11248.265.camel@twins> X-Enigmail-Version: 1.1.2 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig40343A29FA9B69FFD175B25B" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig40343A29FA9B69FFD175B25B Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Hello! I've finally finished testing patch c308b56b53. Apologies for the delay in reporting back. This time I've compared kernels from 3.2 and 2.6.32 branches. Here's a snapshot of load 15 on different versions: 2.6.32.55-hz-0f004f5a69 12.78 2.6.32.55-no-hz-74f5187ac8 4.42 2.6.32.55-no-hz-0f004f5a69 0.49 2.6.32.55-no-hz-c308b56b53 4.37 3.2.12-hz 12.85 3.2.12-no-hz 0.65 3.2.12-no-hz-c308b56b53 7.25 3.2.12-no-hz-c308b56b53 nohz=3Doff 10.59 A whole day trend is available on a comparison chart [1]. Just to make things clear 2.6.32 kernels were patched as follows: * 74f5187ac8 - just 74f5187ac8 * 0f004f5a69 - 74f5187ac8 + 0f004f5a69 * c308b56b53 - 74f5187ac8 + 0f004f5a69 + c308b56b53 For kernel 3.2.12 patch c308b56b53 seems almost perfect. For low CPU utilization the load value is slightly lower for NO_HZ version than it is for HZ one. However the difference is small and the overall trend relates to CPU usage quite closely. This is definitely the best match so far. Thanks! Looking at results for 2.6.32.55 branch it seems that we're back at 74f5187ac8 patch - the values are almost the same. The difference between NO_HZ and HZ versions is noticeable. At the risk of sounding like an ungrateful bastard - will there be further attempts at fixing this bug for 2.6.32 kernels? [1] http://img535.imageshack.us/img535/2204/kernelload.png --=20 Les=C5=82aw Kope=C4=87 --------------enig40343A29FA9B69FFD175B25B Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAk+NZ40ACgkQNZJfI+JDs2JIMwCgm85X8vDmAjqB9Vu9CICDcOAD TvMAnAhBIm/ZjYHpnidnMkBomHS5jOxf =Nvds -----END PGP SIGNATURE----- --------------enig40343A29FA9B69FFD175B25B--