On Thu, Mar 8, 2018 at 11:29 AM, Claudio Scordino <[email protected]> wrote: > When the SCHED_DEADLINE scheduling class increases the CPU utilization, > we should not wait for the rate limit, otherwise we 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 <[email protected]> > CC: Ingo Molnar <[email protected]> > CC: Patrick Bellasi <[email protected]> > CC: Dietmar Eggemann <[email protected]> > CC: Morten Rasmussen <[email protected]> > CC: Juri Lelli <[email protected]> > CC: Viresh Kumar <[email protected]> > CC: Vincent Guittot <[email protected]> > CC: Todd Kjos <[email protected]> > CC: Joel Fernandes <[email protected]> > CC: [email protected] > CC: [email protected] > --- > Changes from v2: > - Rate limit ignored also in case of "fast switch" > - Specific routine added > --- > Changes from v1: > - Logic moved from sugov_should_update_freq() to > sugov_update_single()/_shared() to not duplicate data structures > - Rate limit not ignored in case of "fast switch" > --- > kernel/sched/cpufreq_schedutil.c | 15 +++++++++++++++ > 1 file changed, 15 insertions(+) > > diff --git a/kernel/sched/cpufreq_schedutil.c > b/kernel/sched/cpufreq_schedutil.c > index 7936f54..13f9cce 100644 > --- a/kernel/sched/cpufreq_schedutil.c > +++ b/kernel/sched/cpufreq_schedutil.c > @@ -260,6 +260,17 @@ 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
I wouldn't break the line here > +void set_dl_rate_limit(struct sugov_cpu *sg_cpu, struct sugov_policy > *sg_policy) and the name might be better as Viresh said, but overall Reviewed-by: Rafael J. Wysocki <[email protected]> > +{ > + 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) > { > @@ -273,6 +284,8 @@ static void sugov_update_single(struct update_util_data > *hook, u64 time, > sugov_set_iowait_boost(sg_cpu, time); > sg_cpu->last_update = time; > > + set_dl_rate_limit(sg_cpu, sg_policy); > + > if (!sugov_should_update_freq(sg_policy, time)) > return; > > @@ -354,6 +367,8 @@ static void sugov_update_shared(struct update_util_data > *hook, u64 time, > > raw_spin_lock(&sg_policy->update_lock); > > + set_dl_rate_limit(sg_cpu, sg_policy); > + > sugov_get_util(sg_cpu); > sg_cpu->flags = flags; > > -- > 2.7.4 >
