From ff383d94478af0bb62f828bad550e42681a7176e Mon Sep 17 00:00:00 2001 From: Joel Fernandes Date: Thu, 18 May 2017 22:46:10 -0700 Subject: FROMLIST: sched: Make iowait_boost optional in schedutil 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% Bug: 38010527 Link: https://lkml.org/lkml/2017/5/19/42 Change-Id: If124076ad0c16ade369253840dedfbf870aff927 Signed-off-by: Joel Fernandes --- kernel/sched/cpufreq_schedutil.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) (limited to 'kernel/sched/cpufreq_schedutil.c') diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c index 6c84b4d28914..6effb44aeb30 100644 --- a/kernel/sched/cpufreq_schedutil.c +++ b/kernel/sched/cpufreq_schedutil.c @@ -33,6 +33,7 @@ struct sugov_tunables { struct gov_attr_set attr_set; unsigned int up_rate_limit_us; unsigned int down_rate_limit_us; + bool iowait_boost_enable; }; struct sugov_policy { @@ -228,6 +229,11 @@ static void sugov_get_util(unsigned long *util, unsigned long *max, u64 time) 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) { if (sg_cpu->iowait_boost_pending) return; @@ -510,12 +516,36 @@ static ssize_t down_rate_limit_us_store(struct gov_attr_set *attr_set, 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 up_rate_limit_us = __ATTR_RW(up_rate_limit_us); static struct governor_attr down_rate_limit_us = __ATTR_RW(down_rate_limit_us); +static struct governor_attr iowait_boost_enable = __ATTR_RW(iowait_boost_enable); static struct attribute *sugov_attributes[] = { &up_rate_limit_us.attr, &down_rate_limit_us.attr, + &iowait_boost_enable.attr, NULL }; @@ -675,6 +705,8 @@ static int sugov_init(struct cpufreq_policy *policy) } } + tunables->iowait_boost_enable = policy->iowait_boost_enable; + policy->governor_data = sg_policy; sg_policy->tunables = tunables; -- cgit v1.2.3