cpufreq/schedutil: Take time spent in interrupts into account (9033ea11) · Commits · 戴 / test

The time spent executing IRQ handlers can be significant but it is not reflected in the utilization of CPU when deciding to choose an OPP. Now that we have access to this metric, schedutil can take it into account when selecting the OPP for a CPU. RQS utilization don't see the time spend under interrupt context and report their value in the normal context time window. We need to compensate this when adding interrupt utilization The CPU utilization is: IRQ util_avg + (1 - IRQ util_avg / max capacity ) * /Sum rq util_avg A test with iperf on hikey (octo arm64) gives the following speedup: iperf -c server_address -r -t 5 w/o patch w/ patch Tx 276 Mbits/sec 304 Mbits/sec +10% Rx 299 Mbits/sec 328 Mbits/sec +9% 8 iterations stdev is lower than 1% Only WFI idle state is enabled (shallowest idle state). Signed-off-by:

Vincent Guittot <vincent.guittot@linaro.org> 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: Morten.Rasmussen@arm.com Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: claudio@evidence.eu.com Cc: daniel.lezcano@linaro.org Cc: dietmar.eggemann@arm.com Cc: joel@joelfernandes.org Cc: juri.lelli@redhat.com Cc: luca.abeni@santannapisa.it Cc: patrick.bellasi@arm.com Cc: quentin.perret@arm.com Cc: rjw@rjwysocki.net Cc: valentin.schneider@arm.com Link: http://lkml.kernel.org/r/1530200714-4504-8-git-send-email-vincent.guittot@linaro.org Signed-off-by:

Ingo Molnar <mingo@kernel.org>

kernel/sched/cpufreq_schedutil.c

+21 −4

Original line number	Diff line number	Diff line
		@@ -58,6 +58,7 @@ struct sugov_cpu {
		unsigned long util_dl;
		unsigned long bw_dl;
		unsigned long util_rt;
		unsigned long util_irq;
		unsigned long max;

		/* The field below is for single-CPU policies only: */
		@@ -190,21 +191,30 @@ static void sugov_get_util(struct sugov_cpu *sg_cpu)
		sg_cpu->util_dl = cpu_util_dl(rq);
		sg_cpu->bw_dl = cpu_bw_dl(rq);
		sg_cpu->util_rt = cpu_util_rt(rq);
		sg_cpu->util_irq = cpu_util_irq(rq);
		}

		static unsigned long sugov_aggregate_util(struct sugov_cpu *sg_cpu)
		{
		struct rq *rq = cpu_rq(sg_cpu->cpu);
		unsigned long util;
		unsigned long util, max = sg_cpu->max;

		if (rt_rq_is_runnable(&rq->rt))
		return sg_cpu->max;

		if (unlikely(sg_cpu->util_irq >= max))
		return max;

		/* Sum rq utilization */
		util = sg_cpu->util_cfs;
		util += sg_cpu->util_rt;

		if ((util + sg_cpu->util_dl) >= sg_cpu->max)
		return sg_cpu->max;
		/*
		* Interrupt time is not seen by RQS utilization so we can compare
		* them with the CPU capacity
		*/
		if ((util + sg_cpu->util_dl) >= max)
		return max;

		/*
		* As there is still idle time on the CPU, we need to compute the
		@@ -220,10 +230,17 @@ static unsigned long sugov_aggregate_util(struct sugov_cpu *sg_cpu)
		* ready for such an interface. So, we only do the latter for now.
		*/

		/* Weight RQS utilization to normal context window */
		util *= (max - sg_cpu->util_irq);
		util /= max;

		/* Add interrupt utilization */
		util += sg_cpu->util_irq;

		/* Add DL bandwidth requirement */
		util += sg_cpu->bw_dl;

		return min(sg_cpu->max, util);
		return min(max, util);
		}

		/**

kernel/sched/sched.h

+13 −0

Original line number	Diff line number	Diff line
		@@ -2228,4 +2228,17 @@ static inline unsigned long cpu_util_rt(struct rq *rq)
		{
		return rq->avg_rt.util_avg;
		}

		#if defined(CONFIG_IRQ_TIME_ACCOUNTING) \|\| defined(CONFIG_PARAVIRT_TIME_ACCOUNTING)
		static inline unsigned long cpu_util_irq(struct rq *rq)
		{
		return rq->avg_irq.util_avg;
		}
		#else
		static inline unsigned long cpu_util_irq(struct rq *rq)
		{
		return 0;
		}

		#endif
		#endif

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