sched/uclamp: Add uclamp_util_with() (9d20ad7d) · Commits · 戴 / test

So far uclamp_util() allows to clamp a specified utilization considering the clamp values requested by RUNNABLE tasks in a CPU. For the Energy Aware Scheduler (EAS) it is interesting to test how clamp values will change when a task is becoming RUNNABLE on a given CPU. For example, EAS is interested in comparing the energy impact of different scheduling decisions and the clamp values can play a role on that. Add uclamp_util_with() which allows to clamp a given utilization by considering the possible impact on CPU clamp values of a specified task. Signed-off-by:

Patrick Bellasi <patrick.bellasi@arm.com> Signed-off-by:

Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alessio Balsini <balsini@android.com> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Joel Fernandes <joelaf@google.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: Paul Turner <pjt@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Quentin Perret <quentin.perret@arm.com> Cc: Rafael J . Wysocki <rafael.j.wysocki@intel.com> Cc: Steve Muckle <smuckle@google.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Todd Kjos <tkjos@google.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Viresh Kumar <viresh.kumar@linaro.org> Link: https://lkml.kernel.org/r/20190621084217.8167-11-patrick.bellasi@arm.com Signed-off-by:

Ingo Molnar <mingo@kernel.org>

kernel/sched/core.c

+13 −0

Original line number	Diff line number	Diff line
		@@ -880,6 +880,19 @@ uclamp_eff_get(struct task_struct *p, unsigned int clamp_id)
		return uc_req;
		}

		unsigned int uclamp_eff_value(struct task_struct *p, unsigned int clamp_id)
		{
		struct uclamp_se uc_eff;

		/* Task currently refcounted: use back-annotated (effective) value */
		if (p->uclamp[clamp_id].active)
		return p->uclamp[clamp_id].value;

		uc_eff = uclamp_eff_get(p, clamp_id);

		return uc_eff.value;
		}

		/*
		* When a task is enqueued on a rq, the clamp bucket currently defined by the
		* task's uclamp::bucket_id is refcounted on that rq. This also immediately

kernel/sched/sched.h

+20 −1

Original line number	Diff line number	Diff line
		@@ -2266,11 +2266,20 @@ static inline void cpufreq_update_util(struct rq *rq, unsigned int flags) {}
		#endif /* CONFIG_CPU_FREQ */

		#ifdef CONFIG_UCLAMP_TASK
		static inline unsigned int uclamp_util(struct rq *rq, unsigned int util)
		unsigned int uclamp_eff_value(struct task_struct *p, unsigned int clamp_id);

		static __always_inline
		unsigned int uclamp_util_with(struct rq *rq, unsigned int util,
		struct task_struct *p)
		{
		unsigned int min_util = READ_ONCE(rq->uclamp[UCLAMP_MIN].value);
		unsigned int max_util = READ_ONCE(rq->uclamp[UCLAMP_MAX].value);

		if (p) {
		min_util = max(min_util, uclamp_eff_value(p, UCLAMP_MIN));
		max_util = max(max_util, uclamp_eff_value(p, UCLAMP_MAX));
		}

		/*
		* Since CPU's {min,max}_util clamps are MAX aggregated considering
		* RUNNABLE tasks with _different_ clamps, we can end up with an
		@@ -2281,7 +2290,17 @@ static inline unsigned int uclamp_util(struct rq *rq, unsigned int util)

		return clamp(util, min_util, max_util);
		}

		static inline unsigned int uclamp_util(struct rq *rq, unsigned int util)
		{
		return uclamp_util_with(rq, util, NULL);
		}
		#else /* CONFIG_UCLAMP_TASK */
		static inline unsigned int uclamp_util_with(struct rq *rq, unsigned int util,
		struct task_struct *p)
		{
		return util;
		}
		static inline unsigned int uclamp_util(struct rq *rq, unsigned int util)
		{
		return util;

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