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Date: Wed, 20 Dec 2017 16:30:29 +0100
From: Peter Zijlstra <peterz@...radead.org>
To: Patrick Bellasi <patrick.bellasi@....com>
Cc: linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
Ingo Molnar <mingo@...hat.com>,
"Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
Viresh Kumar <viresh.kumar@...aro.org>,
Vincent Guittot <vincent.guittot@...aro.org>,
Dietmar Eggemann <dietmar.eggemann@....com>,
Morten Rasmussen <morten.rasmussen@....com>,
Juri Lelli <juri.lelli@...hat.com>,
Todd Kjos <tkjos@...roid.com>,
Joel Fernandes <joelaf@...gle.com>
Subject: Re: [PATCH v3 0/6] cpufreq: schedutil: fixes for flags updates
So I ended up with the below (on top of Juri's cpufreq-dl patches).
It compiles, but that's about all the testing it had.
--- a/include/linux/sched/cpufreq.h
+++ b/include/linux/sched/cpufreq.h
@@ -8,9 +8,7 @@
* Interface between cpufreq drivers and the scheduler:
*/
-#define SCHED_CPUFREQ_RT (1U << 0)
-#define SCHED_CPUFREQ_DL (1U << 1)
-#define SCHED_CPUFREQ_IOWAIT (1U << 2)
+#define SCHED_CPUFREQ_IOWAIT (1U << 0)
#ifdef CONFIG_CPU_FREQ
struct update_util_data {
--- a/kernel/sched/cpufreq_schedutil.c
+++ b/kernel/sched/cpufreq_schedutil.c
@@ -63,7 +63,6 @@ struct sugov_cpu {
unsigned long util_cfs;
unsigned long util_dl;
unsigned long max;
- unsigned int flags;
/* The field below is for single-CPU policies only. */
#ifdef CONFIG_NO_HZ_COMMON
@@ -188,17 +187,23 @@ static void sugov_get_util(struct sugov_
static unsigned long sugov_aggregate_util(struct sugov_cpu *sg_cpu)
{
+ unsigned long util = sg_cpu->util_cfs + sg_cpu->util_dl;
+ struct rq *rq = cpu_rq(sg_cpu->cpu);
+
+ if (rq->rt.rt_nr_running)
+ util = sg_cpu->max;
+
/*
* Ideally we would like to set util_dl as min/guaranteed freq and
* util_cfs + util_dl as requested freq. However, cpufreq is not yet
* ready for such an interface. So, we only do the latter for now.
*/
- return min(sg_cpu->util_cfs + sg_cpu->util_dl, sg_cpu->max);
+ return min(util, sg_cpu->max);
}
-static void sugov_set_iowait_boost(struct sugov_cpu *sg_cpu, u64 time)
+static void sugov_set_iowait_boost(struct sugov_cpu *sg_cpu, u64 time, unsigned int flags)
{
- if (sg_cpu->flags & SCHED_CPUFREQ_IOWAIT) {
+ if (flags & SCHED_CPUFREQ_IOWAIT) {
if (sg_cpu->iowait_boost_pending)
return;
@@ -267,12 +272,11 @@ static void sugov_update_single(struct u
{
struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util);
struct sugov_policy *sg_policy = sg_cpu->sg_policy;
- struct cpufreq_policy *policy = sg_policy->policy;
unsigned long util, max;
unsigned int next_f;
bool busy;
- sugov_set_iowait_boost(sg_cpu, time);
+ sugov_set_iowait_boost(sg_cpu, time, flags);
sg_cpu->last_update = time;
if (!sugov_should_update_freq(sg_policy, time))
@@ -280,25 +284,22 @@ static void sugov_update_single(struct u
busy = sugov_cpu_is_busy(sg_cpu);
- if (flags & SCHED_CPUFREQ_RT) {
- next_f = policy->cpuinfo.max_freq;
- } else {
- sugov_get_util(sg_cpu);
- max = sg_cpu->max;
- util = sugov_aggregate_util(sg_cpu);
- sugov_iowait_boost(sg_cpu, &util, &max);
- next_f = get_next_freq(sg_policy, util, max);
- /*
- * Do not reduce the frequency if the CPU has not been idle
- * recently, as the reduction is likely to be premature then.
- */
- if (busy && next_f < sg_policy->next_freq) {
- next_f = sg_policy->next_freq;
+ sugov_get_util(sg_cpu);
+ max = sg_cpu->max;
+ util = sugov_aggregate_util(sg_cpu);
+ sugov_iowait_boost(sg_cpu, &util, &max);
+ next_f = get_next_freq(sg_policy, util, max);
+ /*
+ * Do not reduce the frequency if the CPU has not been idle
+ * recently, as the reduction is likely to be premature then.
+ */
+ if (busy && next_f < sg_policy->next_freq) {
+ next_f = sg_policy->next_freq;
- /* Reset cached freq as next_freq has changed */
- sg_policy->cached_raw_freq = 0;
- }
+ /* Reset cached freq as next_freq has changed */
+ sg_policy->cached_raw_freq = 0;
}
+
sugov_update_commit(sg_policy, time, next_f);
}
@@ -314,6 +315,9 @@ static unsigned int sugov_next_freq_shar
unsigned long j_util, j_max;
s64 delta_ns;
+ if (j_sg_cpu != sg_cpu)
+ sugov_get_util(j_sg_cpu);
+
/*
* If the CFS CPU utilization was last updated before the
* previous frequency update and the time elapsed between the
@@ -327,12 +331,7 @@ static unsigned int sugov_next_freq_shar
if (delta_ns > TICK_NSEC) {
j_sg_cpu->iowait_boost = 0;
j_sg_cpu->iowait_boost_pending = false;
- j_sg_cpu->util_cfs = 0;
- if (j_sg_cpu->util_dl == 0)
- continue;
}
- if (j_sg_cpu->flags & SCHED_CPUFREQ_RT)
- return policy->cpuinfo.max_freq;
j_max = j_sg_cpu->max;
j_util = sugov_aggregate_util(j_sg_cpu);
@@ -357,17 +356,11 @@ static void sugov_update_shared(struct u
raw_spin_lock(&sg_policy->update_lock);
sugov_get_util(sg_cpu);
- sg_cpu->flags = flags;
-
- sugov_set_iowait_boost(sg_cpu, time);
+ sugov_set_iowait_boost(sg_cpu, time, flags);
sg_cpu->last_update = time;
if (sugov_should_update_freq(sg_policy, time)) {
- if (flags & SCHED_CPUFREQ_RT)
- next_f = sg_policy->policy->cpuinfo.max_freq;
- else
- next_f = sugov_next_freq_shared(sg_cpu, time);
-
+ next_f = sugov_next_freq_shared(sg_cpu, time);
sugov_update_commit(sg_policy, time, next_f);
}
@@ -678,7 +671,6 @@ static int sugov_start(struct cpufreq_po
memset(sg_cpu, 0, sizeof(*sg_cpu));
sg_cpu->cpu = cpu;
sg_cpu->sg_policy = sg_policy;
- sg_cpu->flags = 0;
sg_cpu->iowait_boost_max = policy->cpuinfo.max_freq;
}
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -87,7 +87,7 @@ void __add_running_bw(u64 dl_bw, struct
SCHED_WARN_ON(dl_rq->running_bw < old); /* overflow */
SCHED_WARN_ON(dl_rq->running_bw > dl_rq->this_bw);
/* kick cpufreq (see the comment in kernel/sched/sched.h). */
- cpufreq_update_util(rq_of_dl_rq(dl_rq), SCHED_CPUFREQ_DL);
+ cpufreq_update_util(rq_of_dl_rq(dl_rq), 0);
}
static inline
@@ -101,7 +101,7 @@ void __sub_running_bw(u64 dl_bw, struct
if (dl_rq->running_bw > old)
dl_rq->running_bw = 0;
/* kick cpufreq (see the comment in kernel/sched/sched.h). */
- cpufreq_update_util(rq_of_dl_rq(dl_rq), SCHED_CPUFREQ_DL);
+ cpufreq_update_util(rq_of_dl_rq(dl_rq), 0);
}
static inline
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -959,9 +959,6 @@ static void update_curr_rt(struct rq *rq
if (unlikely((s64)delta_exec <= 0))
return;
- /* Kick cpufreq (see the comment in kernel/sched/sched.h). */
- cpufreq_update_util(rq, SCHED_CPUFREQ_RT);
-
schedstat_set(curr->se.statistics.exec_max,
max(curr->se.statistics.exec_max, delta_exec));
@@ -1003,6 +1000,9 @@ dequeue_top_rt_rq(struct rt_rq *rt_rq)
sub_nr_running(rq, rt_rq->rt_nr_running);
rt_rq->rt_queued = 0;
+
+ /* Kick cpufreq (see the comment in kernel/sched/sched.h). */
+ cpufreq_update_util(rq, 0);
}
static void
@@ -1019,6 +1019,9 @@ enqueue_top_rt_rq(struct rt_rq *rt_rq)
add_nr_running(rq, rt_rq->rt_nr_running);
rt_rq->rt_queued = 1;
+
+ /* Kick cpufreq (see the comment in kernel/sched/sched.h). */
+ cpufreq_update_util(rq, 0);
}
#if defined CONFIG_SMP
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