sched/cpufreq: Use the DEADLINE utilization signal

SCHED_DEADLINE tracks active utilization signal with a per dl_rq
variable named running_bw.

Make use of that to drive CPU frequency selection: add up FAIR and
DEADLINE contribution to get the required CPU capacity to handle both
requirements (while RT still selects max frequency).

Co-authored-by: Claudio Scordino <claudio@evidence.eu.com>
Signed-off-by: Juri Lelli <juri.lelli@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luca Abeni <luca.abeni@santannapisa.it>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J . Wysocki <rafael.j.wysocki@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: alessio.balsini@arm.com
Cc: bristot@redhat.com
Cc: dietmar.eggemann@arm.com
Cc: joelaf@google.com
Cc: juri.lelli@redhat.com
Cc: mathieu.poirier@linaro.org
Cc: morten.rasmussen@arm.com
Cc: patrick.bellasi@arm.com
Cc: rjw@rjwysocki.net
Cc: rostedt@goodmis.org
Cc: tkjos@android.com
Cc: tommaso.cucinotta@santannapisa.it
Cc: vincent.guittot@linaro.org
Link: http://lkml.kernel.org/r/20171204102325.5110-2-juri.lelli@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/include/linux/sched/cpufreq.h b/include/linux/sched/cpufreq.h
index d1ad3d825561118c814320b444267a92a87fcd70..0b55834efd46495d7e1b3bf0983592426984138c 100644 (file)
--- a/include/linux/sched/cpufreq.h
+++ b/include/linux/sched/cpufreq.h
@@ -12,8 +12,6 @@
 #define SCHED_CPUFREQ_DL       (1U << 1)
 #define SCHED_CPUFREQ_IOWAIT   (1U << 2)
 
-#define SCHED_CPUFREQ_RT_DL    (SCHED_CPUFREQ_RT | SCHED_CPUFREQ_DL)
-
 #ifdef CONFIG_CPU_FREQ
 struct update_util_data {
        void (*func)(struct update_util_data *data, u64 time, unsigned int flags);

diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
index 6dd1ec9e2995df9d0b70e93efd82eba71a048552..8d266bc5c67de3dd8e1e1cbcaf1e8bd4ae038beb 100644 (file)
--- a/kernel/sched/cpufreq_schedutil.c
+++ b/kernel/sched/cpufreq_schedutil.c
@@ -179,12 +179,17 @@ static unsigned int get_next_freq(struct sugov_policy *sg_policy,
 static void sugov_get_util(unsigned long *util, unsigned long *max, int cpu)
 {
        struct rq *rq = cpu_rq(cpu);
-       unsigned long cfs_max;
+       unsigned long util_cfs = cpu_util_cfs(rq);
+       unsigned long util_dl  = cpu_util_dl(rq);
 
-       cfs_max = arch_scale_cpu_capacity(NULL, cpu);
+       *max = arch_scale_cpu_capacity(NULL, cpu);
 
-       *util = min(rq->cfs.avg.util_avg, cfs_max);
-       *max = cfs_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.
+        */
+       *util = min(util_cfs + util_dl, *max);
 }
 
 static void sugov_set_iowait_boost(struct sugov_cpu *sg_cpu, u64 time)
@@ -271,7 +276,7 @@ static void sugov_update_single(struct update_util_data *hook, u64 time,
 
        busy = sugov_cpu_is_busy(sg_cpu);
 
-       if (flags & SCHED_CPUFREQ_RT_DL) {
+       if (flags & SCHED_CPUFREQ_RT) {
                next_f = policy->cpuinfo.max_freq;
        } else {
                sugov_get_util(&util, &max, sg_cpu->cpu);
@@ -316,7 +321,7 @@ static unsigned int sugov_next_freq_shared(struct sugov_cpu *sg_cpu, u64 time)
                        j_sg_cpu->iowait_boost_pending = false;
                        continue;
                }
-               if (j_sg_cpu->flags & SCHED_CPUFREQ_RT_DL)
+               if (j_sg_cpu->flags & SCHED_CPUFREQ_RT)
                        return policy->cpuinfo.max_freq;
 
                j_util = j_sg_cpu->util;
@@ -352,7 +357,7 @@ static void sugov_update_shared(struct update_util_data *hook, u64 time,
        sg_cpu->last_update = time;
 
        if (sugov_should_update_freq(sg_policy, time)) {
-               if (flags & SCHED_CPUFREQ_RT_DL)
+               if (flags & SCHED_CPUFREQ_RT)
                        next_f = sg_policy->policy->cpuinfo.max_freq;
                else
                        next_f = sugov_next_freq_shared(sg_cpu, time);
@@ -382,9 +387,9 @@ static void sugov_irq_work(struct irq_work *irq_work)
        sg_policy = container_of(irq_work, struct sugov_policy, irq_work);
 
        /*
-        * For RT and deadline tasks, the schedutil governor shoots the
-        * frequency to maximum. Special care must be taken to ensure that this
-        * kthread doesn't result in the same behavior.
+        * For RT tasks, the schedutil governor shoots the frequency to maximum.
+        * Special care must be taken to ensure that this kthread doesn't result
+        * in the same behavior.
         *
         * This is (mostly) guaranteed by the work_in_progress flag. The flag is
         * updated only at the end of the sugov_work() function and before that

diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 43f5d6e936bba9cf0ca1e77dd353325a6241bc1e..136ab500daeb339fd44a3b18b7357b8c5c47662e 100644 (file)
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -2084,3 +2084,13 @@ static inline void cpufreq_update_util(struct rq *rq, unsigned int flags) {}
 #else /* arch_scale_freq_capacity */
 #define arch_scale_freq_invariant()    (false)
 #endif
+
+static inline unsigned long cpu_util_dl(struct rq *rq)
+{
+       return (rq->dl.running_bw * SCHED_CAPACITY_SCALE) >> BW_SHIFT;
+}
+
+static inline unsigned long cpu_util_cfs(struct rq *rq)
+{
+       return rq->cfs.avg.util_avg;
+}