Messages in this thread | | | Date | Fri, 6 Jul 2018 11:30:33 +0530 | From | Viresh Kumar <> | Subject | Re: [PATCH 07/11] cpufreq/schedutil: take into account interrupt |
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On 28-06-18, 17:45, Vincent Guittot wrote: > The time spent under interrupt 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: > 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 +09% > > 8 iterations > stdev is lower than 1% > Only WFI idle state is enable (shallowest diel state) > > Cc: Ingo Molnar <mingo@redhat.com> > Cc: Peter Zijlstra <peterz@infradead.org> > Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> > --- > kernel/sched/cpufreq_schedutil.c | 25 +++++++++++++++++++++---- > kernel/sched/sched.h | 13 +++++++++++++ > 2 files changed, 34 insertions(+), 4 deletions(-) > > diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c > index edfbfc1..b77bfef 100644 > --- a/kernel/sched/cpufreq_schedutil.c > +++ b/kernel/sched/cpufreq_schedutil.c > @@ -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 (rq->rt.rt_nr_running) > 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 nso we can compare
nso ?
> + * 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); > } > > /** > diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h > index 377be2b..9438e68 100644 > --- a/kernel/sched/sched.h > +++ b/kernel/sched/sched.h > @@ -2221,4 +2221,17 @@ 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
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
-- viresh
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