From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752810AbZBAIcR (ORCPT ); Sun, 1 Feb 2009 03:32:17 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751667AbZBAIcB (ORCPT ); Sun, 1 Feb 2009 03:32:01 -0500 Received: from mga11.intel.com ([192.55.52.93]:59210 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751627AbZBAIcA (ORCPT ); Sun, 1 Feb 2009 03:32:00 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.37,359,1231142400"; d="scan'208";a="427144009" Subject: Re: hackbench [pthread mode] regression with 2.6.29-rc3 From: Lin Ming To: peterz@infradead.org Cc: "Zhang, Yanmin" , linux-kernel In-Reply-To: References: <1233473426.2604.13.camel@ymzhang> Content-Type: text/plain Date: Sun, 01 Feb 2009 16:29:21 +0800 Message-Id: <1233476961.13659.12.camel@minggr.sh.intel.com> Mime-Version: 1.0 X-Mailer: Evolution 2.24.1 (2.24.1-2.fc10) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > Bisect located below patch. > commit 490dea45d00f01847ebebd007685d564aaf2cd98 > Author: Peter Zijlstra > Date: Mon Nov 24 17:06:57 2008 +0100 > > itimers: remove the per-cpu-ish-ness > > Either we bounce once cacheline per cpu per tick, yielding n^2 bounces > or we just bounce a single.. > > Also, using per-cpu allocations for the thread-groups complicates the > per-cpu allocator in that its currently aimed to be a fixed sized > allocator and the only possible extention to that would be vmap based, > which is seriously constrained on 32 bit archs. > > > After above patch is reverted, hackbench result is restored. oltp has ~3% regression with 2.6.29-rc3 on 4core*2p stokley machine. After above patch reverted, the regression disappeared. Lin Ming