Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261993AbVDDCK1 (ORCPT ); Sun, 3 Apr 2005 22:10:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261972AbVDDCJH (ORCPT ); Sun, 3 Apr 2005 22:09:07 -0400 Received: from smtp208.mail.sc5.yahoo.com ([216.136.130.116]:32614 "HELO smtp208.mail.sc5.yahoo.com") by vger.kernel.org with SMTP id S261973AbVDDCI3 (ORCPT ); Sun, 3 Apr 2005 22:08:29 -0400 Message-ID: <4250A195.5030306@yahoo.com.au> Date: Mon, 04 Apr 2005 12:08:21 +1000 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.5) Gecko/20050105 Debian/1.7.5-1 X-Accept-Language: en MIME-Version: 1.0 To: Paul Jackson CC: Ingo Molnar , kenneth.w.chen@intel.com, torvalds@osdl.org, akpm@osdl.org, linux-kernel@vger.kernel.org Subject: Re: [patch] sched: auto-tune migration costs [was: Re: Industry db benchmark result on recent 2.6 kernels] References: <200504020100.j3210fg04870@unix-os.sc.intel.com> <20050402145351.GA11601@elte.hu> <20050402215332.79ff56cc.pj@engr.sgi.com> <20050403070415.GA18893@elte.hu> <20050403043420.212290a8.pj@engr.sgi.com> <20050403071227.666ac33d.pj@engr.sgi.com> <20050403152413.GA26631@elte.hu> <20050403160807.35381385.pj@engr.sgi.com> In-Reply-To: <20050403160807.35381385.pj@engr.sgi.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1145 Lines: 30 Paul Jackson wrote: > Ingo wrote: > >>if you create a sched-domains hierarchy (based on the SLIT tables, or in >>whatever other way) that matches the CPU hierarchy then you'll >>automatically get the proper distances detected. > > > Yes - agreed. I should push in the direction of improving the > SN2 sched domain hierarchy. > I'd just be a bit careful about this. Your biggest systems will have what? At least 7 or 8 domains if you're just going by the number of hops, right? And maybe more if there is more to your topology than just number of hops. sched-domains firstly has a few problems even with your 2 level NUMA domains (although I'm looking at fixing them if possible), but also everything just has to do more work as you traverse the domains and scan all CPUs for balancing opportunities. And its not like the cpu scheduler uses any sort of exact science to make choices... Nick - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/