From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754724AbZDNJfb (ORCPT ); Tue, 14 Apr 2009 05:35:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751305AbZDNJfW (ORCPT ); Tue, 14 Apr 2009 05:35:22 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:45621 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751035AbZDNJfV (ORCPT ); Tue, 14 Apr 2009 05:35:21 -0400 Date: Tue, 14 Apr 2009 11:34:41 +0200 From: Ingo Molnar To: "Paul E. McKenney" Cc: linux-kernel@vger.kernel.org, anton@samba.org, akpm@linux-foundation.org, dipankar@in.ibm.com, manfred@colorfullife.com, cl@linux-foundation.org, josht@linux.vnet.ibm.com, schamp@sgi.com, niv@us.ibm.com, dvhltc@us.ibm.com, ego@in.ibm.com, laijs@cn.fujitsu.com, rostedt@goodmis.org, peterz@infradead.org, penberg@cs.helsinki.fi, andi@firstfloor.org, tglx@linutronix.de Subject: Re: [PATCH 0/3] v2 Make hierarchical RCU less IPI-happy and add more tracing Message-ID: <20090414093441.GA3558@elte.hu> References: <1239683478419-git-send-email-> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1239683478419-git-send-email-> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Paul E. McKenney wrote: > This three-patch set fixes a hierarchical-RCU performance bug > located by Anton Blanchard. This bug affects certain high-end > floating-point computation-heavy workloads with closely spaced > barrier-synchronized iterations, where an interruption of any one > CPU's processing during a given iteration slows the system as a > whole. This bug manifests itself as excessive resched IPIs, and > is strictly a performance regression. It does not affect > correctness. > > The first patch provides the fix for the problem, the second patch > adds the tracing, and the third patch adds the documentation for > the tracing. > > Located-by: Anton Blanchard > Tested-by: Anton Blanchard > Signed-off-by: Paul E. McKenney i've applied the first patch to tip:core/urgent (for .30) and the second and third one to tip:core/rcu (for .31). Thanks Paul, Ingo