From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760186AbcHaKqV (ORCPT ); Wed, 31 Aug 2016 06:46:21 -0400 Received: from mail-pf0-f169.google.com ([209.85.192.169]:33155 "EHLO mail-pf0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759616AbcHaKqQ (ORCPT ); Wed, 31 Aug 2016 06:46:16 -0400 Subject: Re: [PATCH 4/4] cpuidle/menu: add per cpu pm_qos_resume_latency consideration To: open list References: <1472114562-2736-1-git-send-email-alex.shi@linaro.org> <1472114562-2736-4-git-send-email-alex.shi@linaro.org> Cc: linux-pm@vger.kernel.org, Ulf Hansson , Daniel Lezcano , Rasmus Villemoes , Arjan van de Ven , Rik van Riel , "Rafael J. Wysocki" From: Alex Shi Message-ID: <57C6B572.80106@linaro.org> Date: Wed, 31 Aug 2016 18:46:10 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: <1472114562-2736-4-git-send-email-alex.shi@linaro.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Is there any concern on this patch? Regards Alex On 08/25/2016 04:42 PM, Alex Shi wrote: > Kernel or user may have special requirement on cpu response time, like > if a interrupt is pinned to a cpu, we don't want the cpu goes too deep > sleep. This patch can prevent this thing happen by consider per cpu > resume_latency setting in cpu sleep state selection in menu governor. > > The pm_qos_resume_latency ask device to give reponse in this time. That's > similar with cpu cstates' entry_latency + exit_latency. But since > most of cpu cstate either has no entry_latency or add it into exit_latency > So, we just can restrict this time requirement as states exit_latency. > > The 0 value of pm_qos_resume_latency is for no limitation according ABI > definition. So set the value 1 could get the 0 latency if it's needed. > > Signed-off-by: Alex Shi > To: linux-kernel@vger.kernel.org > Cc: linux-pm@vger.kernel.org > Cc: Ulf Hansson > Cc: Daniel Lezcano > Cc: Alex Shi > Cc: Rasmus Villemoes > Cc: Arjan van de Ven > Cc: Rik van Riel > Cc: "Rafael J. Wysocki" > --- > drivers/cpuidle/governors/menu.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c > index bb58e2a..e354880 100644 > --- a/drivers/cpuidle/governors/menu.c > +++ b/drivers/cpuidle/governors/menu.c > @@ -12,6 +12,7 @@ > > #include > #include > +#include > #include > #include > #include > @@ -281,17 +282,23 @@ again: > static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev) > { > struct menu_device *data = this_cpu_ptr(&menu_devices); > + struct device *device = get_cpu_device(dev->cpu); > int latency_req = pm_qos_request(PM_QOS_CPU_DMA_LATENCY); > int i; > unsigned int interactivity_req; > unsigned int expected_interval; > unsigned long nr_iowaiters, cpu_load; > + int resume_latency = dev_pm_qos_read_value(device); > > if (data->needs_update) { > menu_update(drv, dev); > data->needs_update = 0; > } > > + /* resume_latency is 0 means no restriction */ > + if (resume_latency && resume_latency < latency_req) > + latency_req = resume_latency; > + > /* Special case when user has set very strict latency requirement */ > if (unlikely(latency_req == 0)) > return 0; >