From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755825Ab2IYLq3 (ORCPT ); Tue, 25 Sep 2012 07:46:29 -0400 Received: from merlin.infradead.org ([205.233.59.134]:39152 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755444Ab2IYLq2 convert rfc822-to-8bit (ORCPT ); Tue, 25 Sep 2012 07:46:28 -0400 Message-ID: <1348573571.3881.32.camel@twins> Subject: Re: [PATCH 3/3] workqueue: Schedule work on non-idle cpu instead of current one From: Peter Zijlstra To: Viresh Kumar Cc: linux-kernel@vger.kernel.org, pjt@google.com, paul.mckenney@linaro.org, tglx@linutronix.de, tj@kernel.org, suresh.b.siddha@intel.com, venki@google.com, mingo@redhat.com, robin.randhawa@arm.com, Steve.Bannister@arm.com, Arvind.Chauhan@arm.com, amit.kucheria@linaro.org, vincent.guittot@linaro.org, linaro-dev@lists.linaro.org, patches@linaro.org Date: Tue, 25 Sep 2012 13:46:11 +0200 In-Reply-To: <1348573208.3881.27.camel@twins> References: <3232b3192e2e373cc4aaf43359d454c5ad53cddb.1348568074.git.viresh.kumar@linaro.org> <1348572145.3881.18.camel@twins> <1348573208.3881.27.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 On Tue, 2012-09-25 at 13:40 +0200, Peter Zijlstra wrote: > On Tue, 2012-09-25 at 17:00 +0530, Viresh Kumar wrote: > > But this is what the initial idea during LPC we had. > > Yeah.. that's true. > > > Any improvements here you can suggest? > > We could uhm... /me tries thinking ... reuse some of the NOHZ magic? > Would that be sufficient, not waking a NOHZ cpu, or do you really want > not waking any idle cpu? Depending on the trade-off we could have the NOHZ stuff track a non-NOHZ-idle cpu and avoid having to compute one every time we need it.