| Message ID | 1523531671-27491-7-git-send-email-ulf.hansson@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | PM / Domains: Support hierarchical CPU arrangement (PSCI/ARM) | expand |
On Thu, Apr 12, 2018 at 1:14 PM, Ulf Hansson <ulf.hansson@linaro.org> wrote: > From: Lina Iyer <lina.iyer@linaro.org> > > Knowing the sleep duration of CPUs, is known to be needed while selecting > the most energy efficient idle state for a CPU or a group of CPUs. > > However, to be able to compute the sleep duration, we need to know at what > time the next expected wakeup is for the CPU. Therefore, let's export this > information via a new function, tick_nohz_get_next_wakeup(). Following > changes make use of it. > > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Daniel Lezcano <daniel.lezcano@linaro.org> > Cc: Lina Iyer <ilina@codeaurora.org> > Cc: Frederic Weisbecker <fweisbec@gmail.com> > Cc: Ingo Molnar <mingo@kernel.org> > Signed-off-by: Lina Iyer <lina.iyer@linaro.org> > Co-developed-by: Ulf Hansson <ulf.hansson@linaro.org> > Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> > --- > include/linux/tick.h | 10 ++++++++++ > kernel/time/tick-sched.c | 11 +++++++++++ > 2 files changed, 21 insertions(+) > > diff --git a/include/linux/tick.h b/include/linux/tick.h > index 389aa25..d341811 100644 > --- a/include/linux/tick.h > +++ b/include/linux/tick.h > @@ -125,6 +125,7 @@ extern bool tick_nohz_idle_got_tick(void); > extern ktime_t tick_nohz_get_sleep_length(ktime_t *delta_next); > extern unsigned long tick_nohz_get_idle_calls(void); > extern unsigned long tick_nohz_get_idle_calls_cpu(int cpu); > +extern ktime_t tick_nohz_get_next_wakeup(int cpu); > extern u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time); > extern u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time); > > @@ -151,6 +152,15 @@ static inline ktime_t tick_nohz_get_sleep_length(ktime_t *delta_next) > *delta_next = TICK_NSEC; > return *delta_next; > } > + > +static inline ktime_t tick_nohz_get_next_wakeup(int cpu) > +{ > + ktime_t t; > + > + /* Next wake up is the tick period, assume it starts now */ > + return ktime_add(tick_nohz_get_sleep_length(&t), ktime_get()); > +} Well, given that tick_nohz_get_sleep_length() is just the above in this case, wouldn't it be simpler to return ktime_add(ktime_get(), TICK_NSEC) from here? > + > static inline u64 get_cpu_idle_time_us(int cpu, u64 *unused) { return -1; } > static inline u64 get_cpu_iowait_time_us(int cpu, u64 *unused) { return -1; } > > diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c > index 646645e..08db7f3 100644 > --- a/kernel/time/tick-sched.c > +++ b/kernel/time/tick-sched.c > @@ -1098,6 +1098,17 @@ unsigned long tick_nohz_get_idle_calls(void) > return ts->idle_calls; > } > > +/** > + * tick_nohz_get_next_wakeup - return the next wake up of the CPU > + */ > +ktime_t tick_nohz_get_next_wakeup(int cpu) > +{ > + struct clock_event_device *dev = > + per_cpu(tick_cpu_device.evtdev, cpu); I would avoid breaking the line, honestly. If you really really want to avoid going above the 80 chars line length limit, why don't you do struct clock_event_device *dev; dev = per_cpu(tick_cpu_device.evtdev, cpu); > + > + return dev->next_event; > +} > + > static void tick_nohz_account_idle_ticks(struct tick_sched *ts) > { > #ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE > --
diff --git a/include/linux/tick.h b/include/linux/tick.h index 389aa25..d341811 100644 --- a/include/linux/tick.h +++ b/include/linux/tick.h @@ -125,6 +125,7 @@ extern bool tick_nohz_idle_got_tick(void); extern ktime_t tick_nohz_get_sleep_length(ktime_t *delta_next); extern unsigned long tick_nohz_get_idle_calls(void); extern unsigned long tick_nohz_get_idle_calls_cpu(int cpu); +extern ktime_t tick_nohz_get_next_wakeup(int cpu); extern u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time); extern u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time); @@ -151,6 +152,15 @@ static inline ktime_t tick_nohz_get_sleep_length(ktime_t *delta_next) *delta_next = TICK_NSEC; return *delta_next; } + +static inline ktime_t tick_nohz_get_next_wakeup(int cpu) +{ + ktime_t t; + + /* Next wake up is the tick period, assume it starts now */ + return ktime_add(tick_nohz_get_sleep_length(&t), ktime_get()); +} + static inline u64 get_cpu_idle_time_us(int cpu, u64 *unused) { return -1; } static inline u64 get_cpu_iowait_time_us(int cpu, u64 *unused) { return -1; } diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 646645e..08db7f3 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -1098,6 +1098,17 @@ unsigned long tick_nohz_get_idle_calls(void) return ts->idle_calls; } +/** + * tick_nohz_get_next_wakeup - return the next wake up of the CPU + */ +ktime_t tick_nohz_get_next_wakeup(int cpu) +{ + struct clock_event_device *dev = + per_cpu(tick_cpu_device.evtdev, cpu); + + return dev->next_event; +} + static void tick_nohz_account_idle_ticks(struct tick_sched *ts) { #ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE