Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755567AbaJIBXP (ORCPT ); Wed, 8 Oct 2014 21:23:15 -0400 Received: from mga11.intel.com ([192.55.52.93]:18706 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752719AbaJIBXJ (ORCPT ); Wed, 8 Oct 2014 21:23:09 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.04,681,1406617200"; d="scan'208";a="602583572" Message-ID: <5435E275.3030307@intel.com> Date: Thu, 09 Oct 2014 09:18:45 +0800 From: Lan Tianyu User-Agent: Mozilla/5.0 (X11; Linux i686 on x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.0 MIME-Version: 1.0 To: Peter Zijlstra CC: mingo@kernel.org, rafael.j.wysocki@intel.com, toshi.kani@hp.com, akpm@linux-foundation.org, ktkhai@parallels.com, fabf@skynet.be, laijs@cn.fujitsu.com, srivatsa.bhat@linux.vnet.ibm.com, ego@linux.vnet.ibm.com, srivatsa@mit.edu, viresh.kumar@linaro.org, todd.e.brandt@linux.intel.com, tipbot@zytor.com, wangyun@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, Thomas Gleixner Subject: Re: [RFC PATCH V3 0/3] PM/CPU: Parallel enalbing nonboot cpus with resume devices References: <1411633925-9018-1-git-send-email-tianyu.lan@intel.com> <20141008205441.GJ4750@worktop.programming.kicks-ass.net> In-Reply-To: <20141008205441.GJ4750@worktop.programming.kicks-ass.net> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2014年10月09日 04:54, Peter Zijlstra wrote: > On Thu, Sep 25, 2014 at 04:32:02PM +0800, Lan Tianyu wrote: >> This patchset is to parallel enabling nonboot cpus with resuming devices >> during system resume in order to accelerate S2RAM. From test result on >> a 8 logical core Haswell machine, system resume time reduces from 347ms >> to 217ms with this patchset. >> >> In the current world, all nonboot cpus are enabled serially during system >> resume. System resume sequence is that boot cpu enables nonboot cpu one by >> one and then resume devices. Before resuming devices, there are few tasks >> assigned to nonboot cpus after they are brought up. This wastes cpu usage. >> >> This patchset is to allow boot cpu to go forward to resume devices after >> bringing up one nonboot cpu and starting a thread. The thread will be in >> charge of bringing up other frozen cpus. The thread will be scheduled to >> the first online cpu to run . This makes enabling cpu2~x parallel with >> resuming devices. > > So I feel we should really clean up hotplug before doing anything like > this. Its a trainwreck and just piling more and more hacks ontop isn't > going to help any. > Hi Peter: Sorry, I don't know the gap of hotplug clearly. Could you elaborate it? -- Best regards Tianyu Lan -- 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/