From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757898AbZKCDp4 (ORCPT ); Mon, 2 Nov 2009 22:45:56 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757862AbZKCDpz (ORCPT ); Mon, 2 Nov 2009 22:45:55 -0500 Received: from mga09.intel.com ([134.134.136.24]:28639 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757843AbZKCDpz (ORCPT ); Mon, 2 Nov 2009 22:45:55 -0500 X-ExtLoop1: 1 Subject: UDP-U stream performance regression on 32-rc1 kernel From: Alex Shi Reply-To: alex.shi@intel.com To: linux-kernel@vger.kernel.org Cc: mingo@elte.hu, "Zhang, Yanmin" Content-Type: text/plain Organization: intel.com Date: Tue, 03 Nov 2009 11:47:16 +0800 Message-Id: <1257220036.3819.193.camel@alexs-hp.sh.intel.com> Mime-Version: 1.0 X-Mailer: Evolution 2.26.1 (2.26.1-2.fc11) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We found the UDP-U 1k/4k stream of netperf benchmark have some performance regression from 10% to 20% on our Tulsa and some NHM machines. Bisecting found it is due to the following commitment. commit 840a0653100dbde599ae8ddf83fa214dfa5fd1aa Author: Ingo Molnar Date: Fri Sep 4 11:32:54 2009 +0200 sched: Turn on SD_BALANCE_NEWIDLE Start the re-tuning of the balancer by turning on newidle. It improves hackbench performance and parallelism on a 4x4 box. The "perf stat --repeat 10" measurements give us: domain0 domain1 ....................................... -SD_BALANCE_NEWIDLE -SD_BALANCE_NEWIDLE: 2041.273208 task-clock-msecs # 9.354 CPUs ( +- 0.363% ) +SD_BALANCE_NEWIDLE -SD_BALANCE_NEWIDLE: 2086.326925 task-clock-msecs # 11.934 CPUs ( +- 0.301% ) +SD_BALANCE_NEWIDLE +SD_BALANCE_NEWIDLE: 2115.289791 task-clock-msecs # 12.158 CPUs ( +- 0.263% ) BRGs Alex