From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755973AbdKDCzT (ORCPT ); Fri, 3 Nov 2017 22:55:19 -0400 Received: from mga14.intel.com ([192.55.52.115]:58783 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751216AbdKDCzS (ORCPT ); Fri, 3 Nov 2017 22:55:18 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.44,339,1505804400"; d="scan'208";a="169182047" Date: Fri, 3 Nov 2017 19:48:34 -0700 From: Ramesh Thomas To: "Rafael J. Wysocki" Cc: Linux Kernel Mailing List , Linux PM , Rafael Wysocki , Alex Shi , Daniel Lezcano Subject: Re: [PATCH v2] cpuidle: ladder: Add per CPU PM QoS resume latency support Message-ID: <20171104024833.GD29203@intel.com> Reply-To: ramesh.thomas@intel.com References: <20171027020124.GA10233@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2017-10-27 at 09:59:38 +0200, Rafael J. Wysocki wrote: > On Fri, Oct 27, 2017 at 4:01 AM, Ramesh Thomas wrote: > > Individual CPUs may have special requirements to not enter > > deep idle states. For example, a CPU running real time > > applications would not want to enter deep idle states to > > avoid latency impacts. At the same time other CPUs that > > do not have such a requirement could allow deep idle > > states to save power. > > > > This was already implemented in the menu governor. > > Implementing similar changes in the ladder governor which > > gets selected when CONFIG_NO_HZ and CONFIG_NO_HZ_IDLE are not > > set. Refer following commits for the menu governor changes. > > > > commit 9908859acaa9 ("cpuidle/menu: add per CPU PM QoS resume > > latency consideration") > > commit 6dbf5cea05a7 ("cpuidle: menu: Avoid taking spinlock for > > accessing QoS values") > > > > Signed-off-by: Ramesh Thomas > > --- > > > > v2: > > - use PM_QOS_RESUME_LATENCY_NO_CONSTRAINT for "no constraint" value > > Should be applied over https://patchwork.kernel.org/patch/10024157/ > > > > drivers/cpuidle/governors/ladder.c | 7 +++++++ > > 1 file changed, 7 insertions(+) > > > > diff --git a/drivers/cpuidle/governors/ladder.c b/drivers/cpuidle/governors/ladder.c > > index ce1a2ff..1ad8745 100644 > > --- a/drivers/cpuidle/governors/ladder.c > > +++ b/drivers/cpuidle/governors/ladder.c > > @@ -17,6 +17,7 @@ > > #include > > #include > > #include > > +#include > > > > #include > > #include > > @@ -67,10 +68,16 @@ static int ladder_select_state(struct cpuidle_driver *drv, > > struct cpuidle_device *dev) > > { > > struct ladder_device *ldev = this_cpu_ptr(&ladder_devices); > > + struct device *device = get_cpu_device(dev->cpu); > > struct ladder_device_state *last_state; > > int last_residency, last_idx = ldev->last_state_idx; > > int first_idx = drv->states[0].flags & CPUIDLE_FLAG_POLLING ? 1 : 0; > > int latency_req = pm_qos_request(PM_QOS_CPU_DMA_LATENCY); > > + int resume_latency = dev_pm_qos_raw_read_value(device); > > + > > + if (resume_latency < latency_req && > > + resume_latency != PM_QOS_RESUME_LATENCY_NO_CONSTRAINT) > > + latency_req = resume_latency; > > > > /* Special case when user has set very strict latency requirement */ > > if (unlikely(latency_req == 0)) { > > -- > > 2.7.4 > > > > Looks good to me. > > I'll queue it up if nobody objects. > Hi Rafael, This patch would apply as is over your new PM QoS changes. If you need me to repost please let me know. Thanks, Ramesh