Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760825AbZKZQb5 (ORCPT ); Thu, 26 Nov 2009 11:31:57 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760711AbZKZQb4 (ORCPT ); Thu, 26 Nov 2009 11:31:56 -0500 Received: from mtagate2.de.ibm.com ([195.212.17.162]:56745 "EHLO mtagate2.de.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755965AbZKZQb4 (ORCPT ); Thu, 26 Nov 2009 11:31:56 -0500 Message-ID: <4B0EAD7B.90601@linux.vnet.ibm.com> Date: Thu, 26 Nov 2009 17:31:55 +0100 From: Christian Ehrhardt User-Agent: Thunderbird 2.0.0.23 (X11/20090817) MIME-Version: 1.0 To: Peter Zijlstra CC: Ingo Molnar , "linux-kernel@vger.kernel.org" , Holger.Wolf@de.ibm.com, epasch@de.ibm.com, Martin Schwidefsky Subject: Re: Missing recalculation of scheduler tunables in case of cpu hot add/remove References: <4B0EA88E.3030205@linux.vnet.ibm.com> <1259252382.31676.207.camel@laptop> <4B0EAC06.3010407@linux.vnet.ibm.com> <1259252892.31676.220.camel@laptop> In-Reply-To: <1259252892.31676.220.camel@laptop> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1161 Lines: 31 Peter Zijlstra wrote: > On Thu, 2009-11-26 at 17:25 +0100, Christian Ehrhardt wrote: > >>> Aside from that, we probably should put an upper limit in place, as I >>> guess large cpu count machines get silly large values >>> >> I agree to that, but in the code is already an upper limit of >> 200.000.000 - well we might discuss if that is too low/high. >> > > Yeah, I think we should cap it around the 8-16 CPUs. > > ok for me, driven by that finding I think I have to measure different kind of scalings anyway, but as usually that takes some time :-/ At least too time much for the discussion & solution of that bug I guess. The question for now is what we do on cpu hot add/remove? Would hooking somewhere in kernel/cpu.c be the right approach - I'm not quite sure about my own suggestion yet :-). -- Grüsse / regards, Christian Ehrhardt IBM Linux Technology Center, Open Virtualization -- 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/