Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752046Ab2FETte (ORCPT ); Tue, 5 Jun 2012 15:49:34 -0400 Received: from merlin.infradead.org ([205.233.59.134]:37096 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750887Ab2FETtc convert rfc822-to-8bit (ORCPT ); Tue, 5 Jun 2012 15:49:32 -0400 Message-ID: <1338925756.2749.36.camel@twins> Subject: RE: [PATCH 0/6] x86/cpu hotplug: Wake up offline CPU via mwait or nmi From: Peter Zijlstra To: Thomas Gleixner Cc: "Luck, Tony" , "Yu, Fenghua" , Rusty Russell , Ingo Molnar , H Peter Anvin , "Siddha, Suresh B" , "Mallick, Asit K" , Arjan Dan De Ven , linux-kernel , x86 , linux-pm , "Srivatsa S. Bhat" Date: Tue, 05 Jun 2012 21:49:16 +0200 In-Reply-To: References: <1338833876-29721-1-git-send-email-fenghua.yu@intel.com> <1338842001.28282.135.camel@twins> <87zk8iioam.fsf@rustcorp.com.au> <1338881971.28282.150.camel@twins> <3E5A0FA7E9CA944F9D5414FEC6C7122007727023@ORSMSX105.amr.corp.intel.com> <1338912565.2749.9.camel@twins> <3E5A0FA7E9CA944F9D5414FEC6C7122007728081@ORSMSX105.amr.corp.intel.com> <1338913190.2749.10.camel@twins> <3908561D78D1C84285E8C5FCA982C28F19300965@ORSMSX104.amr.corp.intel.com> <1338918625.2749.29.camel@twins> Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT X-Mailer: Evolution 3.2.2- Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1186 Lines: 30 On Tue, 2012-06-05 at 21:43 +0200, Thomas Gleixner wrote: > Vs. the interrupt/timer/other crap madness: > > - We really don't want to have an interrupt balancer in the kernel > again, but we need a mechanism to prevent the user space balancer > trainwreck from ruining the power saving party. What's wrong with having an interrupt balancer tied to the scheduler which optimistically tries to avoid interrupting nohz/isolated/idle cpus? > - The timer issue is mostly solved by the existing nohz stuff > (plus/minus the few bugs in there). Its not.. if you create an isolated domain there's no way to expel existing timers from there. > - The other details (silly IPIs) and cross CPU timer arming) are way > easier to solve by a proper prohibitive state than by chasing that > nonsense all over the tree forever. But we need to solve all that without a prohibitibe state anyway for the isolation stuff to be useful. -- 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/