Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755186Ab1FOLnG (ORCPT ); Wed, 15 Jun 2011 07:43:06 -0400 Received: from casper.infradead.org ([85.118.1.10]:60700 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755142Ab1FOLnC convert rfc822-to-8bit (ORCPT ); Wed, 15 Jun 2011 07:43:02 -0400 Subject: Re: REGRESSION: Performance regressions from switching anon_vma->lock to mutex From: Peter Zijlstra To: Tim Chen Cc: Andrew Morton , Linus Torvalds , Hugh Dickins , KOSAKI Motohiro , Benjamin Herrenschmidt , David Miller , Martin Schwidefsky , Russell King , Paul Mundt , Jeff Dike , Richard Weinberger , Tony Luck , KAMEZAWA Hiroyuki , Mel Gorman , Nick Piggin , Namhyung Kim , ak@linux.intel.com, shaohua.li@intel.com, alex.shi@intel.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, "Rafael J. Wysocki" , paulmck In-Reply-To: <1308135495.15315.38.camel@twins> References: <1308097798.17300.142.camel@schen9-DESK> <1308134200.15315.32.camel@twins> <1308135495.15315.38.camel@twins> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT Date: Wed, 15 Jun 2011 13:41:31 +0200 Message-ID: <1308138091.15315.50.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3259 Lines: 68 On Wed, 2011-06-15 at 12:58 +0200, Peter Zijlstra wrote: > On Wed, 2011-06-15 at 12:36 +0200, Peter Zijlstra wrote: > > On Tue, 2011-06-14 at 17:29 -0700, Tim Chen wrote: > > > MOSBENCH test suite. > > > > Argh, I'm trying to get this thing to run, but its all snake poo.. > > > > /me takes up a heavy club and goes snake hunting, should make a pretty > > hat or something. > > Sweet, I've got meself a snake-skin hat! > > The first thing that stood out when running it was: > > 31694 root 20 0 26660 1460 1212 S 17.5 0.0 0:01.97 exim > 7 root -2 19 0 0 0 S 12.7 0.0 0:06.14 rcuc0 > 24 root -2 19 0 0 0 S 11.7 0.0 0:04.15 rcuc3 > 34 root -2 19 0 0 0 S 11.7 0.0 0:04.10 rcuc5 > 39 root -2 19 0 0 0 S 11.7 0.0 0:06.38 rcuc6 > 44 root -2 19 0 0 0 S 11.7 0.0 0:04.53 rcuc7 > 49 root -2 19 0 0 0 S 11.7 0.0 0:04.11 rcuc8 > 79 root -2 19 0 0 0 S 11.7 0.0 0:03.91 rcuc14 > 89 root -2 19 0 0 0 S 11.7 0.0 0:03.90 rcuc16 > 110 root -2 19 0 0 0 S 11.7 0.0 0:03.90 rcuc20 > 120 root -2 19 0 0 0 S 11.7 0.0 0:03.82 rcuc22 > 13 root -2 19 0 0 0 S 10.7 0.0 0:04.37 rcuc1 > 19 root -2 19 0 0 0 S 10.7 0.0 0:04.19 rcuc2 > 29 root -2 19 0 0 0 S 10.7 0.0 0:04.12 rcuc4 > 54 root -2 19 0 0 0 S 10.7 0.0 0:04.11 rcuc9 > 59 root -2 19 0 0 0 S 10.7 0.0 0:04.40 rcuc10 > 64 root -2 19 0 0 0 R 10.7 0.0 0:04.17 rcuc11 > 69 root -2 19 0 0 0 R 10.7 0.0 0:04.23 rcuc12 > 84 root -2 19 0 0 0 S 10.7 0.0 0:03.90 rcuc15 > 95 root -2 19 0 0 0 S 10.7 0.0 0:03.99 rcuc17 > 100 root -2 19 0 0 0 S 10.7 0.0 0:03.88 rcuc18 > 105 root -2 19 0 0 0 S 10.7 0.0 0:04.14 rcuc19 > 125 root -2 19 0 0 0 S 10.7 0.0 0:03.79 rcuc23 > 74 root -2 19 0 0 0 S 9.7 0.0 0:04.33 rcuc13 > 115 root -2 19 0 0 0 R 9.7 0.0 0:03.82 rcuc21 > > Which is an impressive amount of RCU usage.. FWIW, Alex Shi's patch: http://lkml.kernel.org/r/1308029185.15392.147.camel@sli10-conroe Improves the situation to: 3745 root 20 0 26664 1460 1212 S 18.5 0.0 0:01.28 exim 39 root -2 19 0 0 0 S 4.9 0.0 0:02.83 rcuc6 105 root -2 19 0 0 0 S 4.9 0.0 0:02.79 rcuc19 7 root -2 19 0 0 0 S 3.9 0.0 0:02.70 rcuc0 13 root -2 19 0 0 0 S 3.9 0.0 0:02.54 rcuc1 19 root -2 19 0 0 0 S 3.9 0.0 0:02.76 rcuc2 24 root -2 19 0 0 0 S 3.9 0.0 0:02.75 rcuc3 ... And throughput increases like: -tip 260.092 messages/sec/core -tip+sirq-rcu 271.078 messages/sec/core -- 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/