From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752676AbXCEFBl (ORCPT ); Mon, 5 Mar 2007 00:01:41 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752677AbXCEFBl (ORCPT ); Mon, 5 Mar 2007 00:01:41 -0500 Received: from mga09.intel.com ([134.134.136.24]:28884 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752676AbXCEFBk (ORCPT ); Mon, 5 Mar 2007 00:01:40 -0500 X-ExtLoop1: 1 X-IronPort-AV: i="4.14,247,1170662400"; d="scan'208"; a="52998885:sNHT17991504" Date: Sun, 4 Mar 2007 20:24:53 -0800 From: "Siddha, Suresh B" To: Nick Piggin Cc: "Siddha, Suresh B" , akpm@linux-foundation.org, mingo@elte.hu, linux-kernel@vger.kernel.org Subject: Re: [patch] sched: optimize siblings status check logic in wake_idle() Message-ID: <20070304202453.D27368@unix-os.sc.intel.com> References: <20070302202331.B27368@unix-os.sc.intel.com> <20070305023534.GB16666@wotan.suse.de> <20070304201309.C27368@unix-os.sc.intel.com> <20070305045831.GA2972@wotan.suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: <20070305045831.GA2972@wotan.suse.de>; from npiggin@suse.de on Mon, Mar 05, 2007 at 05:58:31AM +0100 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 05, 2007 at 05:58:31AM +0100, Nick Piggin wrote: > On Sun, Mar 04, 2007 at 08:13:09PM -0800, Suresh B wrote: > > On a 16 node system, we have seen ~1.25% perf improvement on a database workload > > when we completely short circuited wake_idle(). This patch is trying to comeup > > with a best compromise to avoid the cache misses and also minimize the latenices, > > perf impact. > > Hmm, I wonder what if we only wake_idle if the wakeup comes from this > CPU or a sibling? That's probably going to have downsides in some > workloads as well, though. yep. I thought about it and thought this patch is a decent solution. thanks, suresh