sched/cpufreq: Rate limits for SCHED_DEADLINE (e97a90f7) · Commits · 戴 / test

When the SCHED_DEADLINE scheduling class increases the CPU utilization, it should not wait for the rate limit, otherwise it may miss some deadline. Tests using rt-app on Exynos5422 with up to 10 SCHED_DEADLINE tasks have shown reductions of even 10% of deadline misses with a negligible increase of energy consumption (measured through Baylibre Cape). Signed-off-by:

Claudio Scordino <claudio@evidence.eu.com> Signed-off-by:

Thomas Gleixner <tglx@linutronix.de> Reviewed-by:

Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by:

Viresh Kumar <viresh.kumar@linaro.org> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Joel Fernandes <joelaf@google.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: linux-pm@vger.kernel.org Cc: Peter Zijlstra <peterz@infradead.org> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: Patrick Bellasi <patrick.bellasi@arm.com> Cc: Todd Kjos <tkjos@android.com> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Link: https://lkml.kernel.org/r/1520937340-2755-1-git-send-email-claudio@evidence.eu.com

kernel/sched/cpufreq_schedutil.c

+14 −0

Original line number	Diff line number	Diff line
		@@ -267,6 +267,16 @@ static bool sugov_cpu_is_busy(struct sugov_cpu *sg_cpu)
		static inline bool sugov_cpu_is_busy(struct sugov_cpu *sg_cpu) { return false; }
		#endif /* CONFIG_NO_HZ_COMMON */

		/*
		* Make sugov_should_update_freq() ignore the rate limit when DL
		* has increased the utilization.
		*/
		static inline void ignore_dl_rate_limit(struct sugov_cpu sg_cpu, struct sugov_policy sg_policy)
		{
		if (cpu_util_dl(cpu_rq(sg_cpu->cpu)) > sg_cpu->util_dl)
		sg_policy->need_freq_update = true;
		}

		static void sugov_update_single(struct update_util_data *hook, u64 time,
		unsigned int flags)
		{
		@@ -279,6 +289,8 @@ static void sugov_update_single(struct update_util_data *hook, u64 time,
		sugov_set_iowait_boost(sg_cpu, time, flags);
		sg_cpu->last_update = time;

		ignore_dl_rate_limit(sg_cpu, sg_policy);

		if (!sugov_should_update_freq(sg_policy, time))
		return;

		@@ -356,6 +368,8 @@ sugov_update_shared(struct update_util_data *hook, u64 time, unsigned int flags)
		sugov_set_iowait_boost(sg_cpu, time, flags);
		sg_cpu->last_update = time;

		ignore_dl_rate_limit(sg_cpu, sg_policy);

		if (sugov_should_update_freq(sg_policy, time)) {
		next_f = sugov_next_freq_shared(sg_cpu, time);
		sugov_update_commit(sg_policy, time, next_f);

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