From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752667Ab0AYLpV (ORCPT ); Mon, 25 Jan 2010 06:45:21 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752596Ab0AYLpS (ORCPT ); Mon, 25 Jan 2010 06:45:18 -0500 Received: from mail.gmx.net ([213.165.64.20]:53616 "HELO mail.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1752128Ab0AYLpS (ORCPT ); Mon, 25 Jan 2010 06:45:18 -0500 X-Authenticated: #14349625 X-Provags-ID: V01U2FsdGVkX19rfcYFMQhrNVo7Aaeq3vcvQFQ8EfRBgMmR2ZurAt R/iKxl1genRbiL Subject: Re: netperf ~50% regression with 2.6.33-rc1, bisect to 1b9508f From: Mike Galbraith To: Lin Ming Cc: Peter Zijlstra , Ingo Molnar , "Zhang, Yanmin" , lkml In-Reply-To: <1264419342.5888.42.camel@marge.simson.net> References: <1264413826.3642.88.camel@minggr.sh.intel.com> <1264419342.5888.42.camel@marge.simson.net> Content-Type: text/plain Date: Mon, 25 Jan 2010 12:45:13 +0100 Message-Id: <1264419913.5888.49.camel@marge.simson.net> Mime-Version: 1.0 X-Mailer: Evolution 2.24.1.1 Content-Transfer-Encoding: 7bit X-Y-GMX-Trusted: 0 X-FuHaFi: 0.70999999999999996 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2010-01-25 at 12:35 +0100, Mike Galbraith wrote: > So. Rummaging around doing absolutely _nothing_ useful, there being > zero movable tasks in this load, prevents us switching to the idle > thread before the scheduling task is requeued. Oh joy. Wait a minute. The only way that can work is if we hit contended lock, and drop our rq lock (and where would busiest->nr_running > 1 come from with a 2 task load?) Puzzled. -Mike