From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756182AbXHAWrJ (ORCPT ); Wed, 1 Aug 2007 18:47:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754365AbXHAWq4 (ORCPT ); Wed, 1 Aug 2007 18:46:56 -0400 Received: from mga05.intel.com ([192.55.52.89]:52746 "EHLO fmsmga101.fm.intel.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753587AbXHAWqz (ORCPT ); Wed, 1 Aug 2007 18:46:55 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.19,210,1183359600"; d="scan'208";a="275409575" Subject: Re: [patch] sched: yield debugging From: Tim Chen Reply-To: tim.c.chen@linux.intel.com To: Ingo Molnar Cc: linux-kernel@vger.kernel.org In-Reply-To: <20070731203351.GB21667@elte.hu> References: <1185573687.19777.44.camel@localhost.localdomain> <20070729173735.GA4041@elte.hu> <1185819052.19777.52.camel@localhost.localdomain> <20070731203351.GB21667@elte.hu> Content-Type: text/plain Organization: Intel Date: Wed, 01 Aug 2007 13:53:37 -0700 Message-Id: <1186001617.19777.64.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.0.2 (2.0.2-8) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2007-07-31 at 22:33 +0200, Ingo Molnar wrote: > ok, good! Could you try the updated debug patch below? I've done two > changes: made '1' the default, and added the > /proc/sys/kernel/sched_yield_granularity_ns tunable. (available if > CONFIG_SCHED_DEBUG=y) > > Could you try to change the yield-granularity tunable and see which > value gives the best performance? A value of '100000' should in theory > give the current (80% degraded) volanomark performance, the default > value should give the above '20% down' result. The question is, is '20% > down' the best we can get out of it? Does larger/smaller > yield-granularity help perhaps? You can change it to any value between > 100 usecs and 1 second. > Turning up the granuality helped. Here's the data I got for Volanomark performance relative to 2.6.22 Granuality 1000000000 (max) 9% down 800000000 8% down 80000000 13% down 8000000 20% down 100000 56% down Tim