From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932148AbdESGYM (ORCPT ); Fri, 19 May 2017 02:24:12 -0400 Received: from mail-pg0-f51.google.com ([74.125.83.51]:34122 "EHLO mail-pg0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755636AbdESGYE (ORCPT ); Fri, 19 May 2017 02:24:04 -0400 From: Joel Fernandes To: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Joel Fernandes , Srinivas Pandruvada , Len Brown , "Rafael J . Wysocki" , Viresh Kumar , Ingo Molnar , Peter Zijlstra Subject: [PATCH v2 2/2] sched: Make iowait_boost optional in schedutil Date: Thu, 18 May 2017 23:23:44 -0700 Message-Id: <20170519062344.27692-3-joelaf@google.com> X-Mailer: git-send-email 2.13.0.303.g4ebf302169-goog In-Reply-To: <20170519062344.27692-1-joelaf@google.com> References: <20170519062344.27692-1-joelaf@google.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We should apply the iowait boost only if cpufreq policy has iowait boost enabled. Also make it a schedutil configuration from sysfs so it can be turned on/off if needed (by default initialize it to the policy value). For systems that don't need/want it enabled, such as those on arm64 based mobile devices that are battery operated, it saves energy when the cpufreq driver policy doesn't have it enabled (details below): Here are some results for energy measurements collected running a YouTube video for 30 seconds: Before: 8.042533 mWh After: 7.948377 mWh Energy savings is ~1.2% Cc: Srinivas Pandruvada Cc: Len Brown Cc: Rafael J. Wysocki Cc: Viresh Kumar Cc: Ingo Molnar Cc: Peter Zijlstra Signed-off-by: Joel Fernandes --- kernel/sched/cpufreq_schedutil.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c index 76877a62b5fa..0e392b58b9b3 100644 --- a/kernel/sched/cpufreq_schedutil.c +++ b/kernel/sched/cpufreq_schedutil.c @@ -24,6 +24,7 @@ struct sugov_tunables { struct gov_attr_set attr_set; unsigned int rate_limit_us; + bool iowait_boost_enable; }; struct sugov_policy { @@ -171,6 +172,11 @@ static void sugov_get_util(unsigned long *util, unsigned long *max) static void sugov_set_iowait_boost(struct sugov_cpu *sg_cpu, u64 time, unsigned int flags) { + struct sugov_policy *sg_policy = sg_cpu->sg_policy; + + if (!sg_policy->tunables->iowait_boost_enable) + return; + if (flags & SCHED_CPUFREQ_IOWAIT) { sg_cpu->iowait_boost = sg_cpu->iowait_boost_max; } else if (sg_cpu->iowait_boost) { @@ -386,10 +392,34 @@ static ssize_t rate_limit_us_store(struct gov_attr_set *attr_set, const char *bu return count; } +static ssize_t iowait_boost_enable_show(struct gov_attr_set *attr_set, + char *buf) +{ + struct sugov_tunables *tunables = to_sugov_tunables(attr_set); + + return sprintf(buf, "%u\n", tunables->iowait_boost_enable); +} + +static ssize_t iowait_boost_enable_store(struct gov_attr_set *attr_set, + const char *buf, size_t count) +{ + struct sugov_tunables *tunables = to_sugov_tunables(attr_set); + bool enable; + + if (kstrtobool(buf, &enable)) + return -EINVAL; + + tunables->iowait_boost_enable = enable; + + return count; +} + static struct governor_attr rate_limit_us = __ATTR_RW(rate_limit_us); +static struct governor_attr iowait_boost_enable = __ATTR_RW(iowait_boost_enable); static struct attribute *sugov_attributes[] = { &rate_limit_us.attr, + &iowait_boost_enable.attr, NULL }; @@ -543,6 +573,8 @@ static int sugov_init(struct cpufreq_policy *policy) tunables->rate_limit_us *= lat; } + tunables->iowait_boost_enable = policy->iowait_boost_enable; + policy->governor_data = sg_policy; sg_policy->tunables = tunables; -- 2.13.0.303.g4ebf302169-goog