Messages in this thread Patches in this message | | | Date | Fri, 29 Apr 2022 01:22:19 +0800 | From | Tao Zhou <> | Subject | Re: [PATCH v7 2/7] sched/fair: Decay task PELT values during wakeup migration |
| |
Hi Vincent,
On Thu, Apr 28, 2022 at 03:38:39PM +0200, Vincent Guittot wrote:
> On Wed, 27 Apr 2022 at 19:37, Tao Zhou <tao.zhou@linux.dev> wrote: > > > > On Wed, Apr 27, 2022 at 03:32:59PM +0100, Vincent Donnefort wrote: > > > Before being migrated to a new CPU, a task sees its PELT values > > > synchronized with rq last_update_time. Once done, that same task will also > > > have its sched_avg last_update_time reset. This means the time between > > > the migration and the last clock update (B) will not be accounted for in > > > util_avg and a discontinuity will appear. This issue is amplified by the > > > PELT clock scaling. If the clock hasn't been updated while the CPU is > > > idle, clock_pelt will not be aligned with clock_task and that time (A) > > > will be also lost. > > > > > > ---------|----- A -----|-----------|------- B -----|> > > > clock_pelt clock_task clock now > > > > > > This is especially problematic for asymmetric CPU capacity systems which > > > need stable util_avg signals for task placement and energy estimation. > > > > > > Ideally, this problem would be solved by updating the runqueue clocks > > > before the migration. But that would require taking the runqueue lock > > > which is quite expensive [1]. Instead estimate the missing time and update > > > the task util_avg with that value: > > > > > > A + B = clock_task - clock_pelt + sched_clock_cpu() - clock > > > > > > sched_clock_cpu() is a costly function. Limit the usage to the case where > > > the source CPU is idle as we know this is when the clock is having the > > > biggest risk of being outdated. > > > > > > Neither clock_task, clock_pelt nor clock can be accessed without the > > > runqueue lock. We then need to store those values in a timestamp variable > > > which can be accessed during the migration. rq's enter_idle will give the > > > wall-clock time when the rq went idle. We have then: > > > > > > B = sched_clock_cpu() - rq->enter_idle. > > > > > > Then, to catch-up the PELT clock scaling (A), two cases: > > > > > > * !CFS_BANDWIDTH: We can simply use clock_task(). This value is stored > > > in rq's clock_pelt_idle, before the rq enters idle. The estimated time > > > is then: > > > > > > rq->clock_pelt_idle + sched_clock_cpu() - rq->enter_idle. > > > > > > * CFS_BANDWIDTH: We can't catch-up with clock_task because of the > > > throttled_clock_task_time offset. cfs_rq's clock_pelt_idle is then > > > giving the PELT clock when the cfs_rq becomes idle. This gives: > > > > > > A = rq->clock_pelt_idle - cfs_rq->clock_pelt_idle > > > > > > And gives the following estimated time: > > > > > > cfs_rq->last_update_time + > > > rq->clock_pelt_idle - cfs_rq->clock_pelt_idle + (A) > > > sched_clock_cpu() - rq->enter_idle (B) > > > > > > The (B) part of the missing time is however an estimation that doesn't > > > take into account IRQ and Paravirt time. > > > > > > [1] https://lore.kernel.org/all/20190709115759.10451-1-chris.redpath@arm.com/ > > > > > > Signed-off-by: Vincent Donnefort <vincent.donnefort@arm.com> > > > > > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > > > index abd1feeec0c2..9cd506dc682c 100644 > > > --- a/kernel/sched/fair.c > > > +++ b/kernel/sched/fair.c > > > @@ -3694,6 +3694,57 @@ static inline void add_tg_cfs_propagate(struct cfs_rq *cfs_rq, long runnable_sum > > > > > > #endif /* CONFIG_FAIR_GROUP_SCHED */ > > > > > > +#ifdef CONFIG_NO_HZ_COMMON > > > +static inline void migrate_se_pelt_lag(struct sched_entity *se) > > > +{ > > > + struct cfs_rq *cfs_rq; > > > + struct rq *rq; > > > + bool is_idle; > > > + u64 now; > > > + > > would it make sense to check if pelt value of the task are not fully > decayed before starting the below : ie after syncing with > last_update_time of the cfs
The below diff include this check in.
> > > + cfs_rq = cfs_rq_of(se); > > > + rq = rq_of(cfs_rq); > > > + > > > + rcu_read_lock(); > > > + is_idle = is_idle_task(rcu_dereference(rq->curr)); > > > + rcu_read_unlock(); > > > + > > > + /* > > > + * The lag estimation comes with a cost we don't want to pay all the > > > + * time. Hence, limiting to the case where the source CPU is idle and > > > + * we know we are at the greatest risk to have an outdated clock. > > > + */ > > > + if (!is_idle) > > > + return; > > > + > > > + /* > > > + * estimated "now" is: > > > + * last_update_time + > > > + * PELT scaling (rq->clock_pelt_idle - cfs_rq->clock_pelt_idle) + > > PELT scaling is in fact the time between cfs becoming idle and rq > becoming idle. Naming it PELT scaling is misleading because even at > max frequency (ie without pelt scaling) we can have this delta. > > > > + * rq clock lag (sched_clock_cpu() - rq->enter_idle) > > and this is the time between rq becoming idle and current time > > > > + * > > > + * The PELT scaling contribution is always 0 when !CFS_BANDWIDTH. > > > + * (see clock_pelt = clock_task in _update_idle_rq_clock_pelt()) > > The contribution becomes 0 because we use the same clock reference > > last_update_time (cfs_clock_pelt when cfs became idle) + > rq->clock_pelt_idle (rq_clock_pelt when rq became idle) - > cfs_rq->clock_pelt_idle (rq_clock_pelt when cfs became idle) > > when !CFS_BANDWIDTH, cfs_clock_pelt == rq_clock_pelt because there is > no throttling offset (which can dynamically change) > so we have: > > last_update_time (rq_clock_pelt when cfs became idle) + > rq->clock_pelt_idle (rq_clock_pelt when rq became idle) - > cfs_rq->clock_pelt_idle (rq_clock_pelt when cfs became idle) > > which is equals to rq->clock_pelt_idle (rq_clock_pelt when rq became idle) > > This also means that we only need a snapshot of the > cfs_rq->throttled_clock_pelt_time when cfs became idle and the > equation becomes like below for CFS_BANDWIDTH > > rq->clock_pelt_idle - snapshot of cfs_rq->throttled_clock_pelt_time > when entering idle > > which remove one u64_u32_load
Include these as comments in the below diff.
> > > + */ > > > +#ifdef CONFIG_CFS_BANDWIDTH > > > + now = u64_u32_load(cfs_rq->clock_pelt_idle); > > > + /* The clock has been stopped for throttling */ > > > + if (now == U64_MAX) > > > + return; > > > + > > > + now = u64_u32_load(rq->clock_pelt_idle) - now; > > > + now += cfs_rq_last_update_time(cfs_rq); > > > +#else > > > + now = u64_u32_load(rq->clock_pelt_idle); > > > +#endif > > > + now += sched_clock_cpu(cpu_of(rq)) - u64_u32_load(rq->enter_idle); > > > + > > > + __update_load_avg_blocked_se(now, se); > > > +} > > > +#else > > > +static void migrate_se_pelt_lag(struct sched_entity *se) {} > > > +#endif > > > + > > > /** > > > * update_cfs_rq_load_avg - update the cfs_rq's load/util averages > > > * @now: current time, as per cfs_rq_clock_pelt() > > > @@ -4429,6 +4480,9 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) > > > */ > > > if ((flags & (DEQUEUE_SAVE | DEQUEUE_MOVE)) != DEQUEUE_SAVE) > > > update_min_vruntime(cfs_rq); > > > + > > > + if (cfs_rq->nr_running == 0) > > > + update_idle_cfs_rq_clock_pelt(cfs_rq); > > > } > > > > > > /* > > > @@ -6946,6 +7000,8 @@ static void detach_entity_cfs_rq(struct sched_entity *se); > > > */ > > > static void migrate_task_rq_fair(struct task_struct *p, int new_cpu) > > > { > > > + struct sched_entity *se = &p->se; > > > + > > > /* > > > * As blocked tasks retain absolute vruntime the migration needs to > > > * deal with this by subtracting the old and adding the new > > > @@ -6953,7 +7009,6 @@ static void migrate_task_rq_fair(struct task_struct *p, int new_cpu) > > > * the task on the new runqueue. > > > */ > > > if (READ_ONCE(p->__state) == TASK_WAKING) { > > > - struct sched_entity *se = &p->se; > > > struct cfs_rq *cfs_rq = cfs_rq_of(se); > > > > > > se->vruntime -= u64_u32_load(cfs_rq->min_vruntime); > > > @@ -6965,25 +7020,29 @@ static void migrate_task_rq_fair(struct task_struct *p, int new_cpu) > > > * rq->lock and can modify state directly. > > > */ > > > lockdep_assert_rq_held(task_rq(p)); > > > - detach_entity_cfs_rq(&p->se); > > > + detach_entity_cfs_rq(se); > > > > > > } else { > > > + remove_entity_load_avg(se); > > > + > > > /* > > > - * We are supposed to update the task to "current" time, then > > > - * its up to date and ready to go to new CPU/cfs_rq. But we > > > - * have difficulty in getting what current time is, so simply > > > - * throw away the out-of-date time. This will result in the > > > - * wakee task is less decayed, but giving the wakee more load > > > - * sounds not bad. > > > + * Here, the task's PELT values have been updated according to > > > + * the current rq's clock. But if that clock hasn't been > > > + * updated in a while, a substantial idle time will be missed, > > > + * leading to an inflation after wake-up on the new rq. > > > + * > > > + * Estimate the missing time from the cfs_rq last_update_time > > > + * and update sched_avg to improve the PELT continuity after > > > + * migration. > > > */ > > > - remove_entity_load_avg(&p->se); > > > + migrate_se_pelt_lag(se); > > > } > > > > > > /* Tell new CPU we are migrated */ > > > - p->se.avg.last_update_time = 0; > > > + se->avg.last_update_time = 0; > > > > > > /* We have migrated, no longer consider this task hot */ > > > - p->se.exec_start = 0; > > > + se->exec_start = 0; > > > > > > update_scan_period(p, new_cpu); > > > } > > > @@ -8149,6 +8208,10 @@ static bool __update_blocked_fair(struct rq *rq, bool *done) > > > if (update_cfs_rq_load_avg(cfs_rq_clock_pelt(cfs_rq), cfs_rq)) { > > > update_tg_load_avg(cfs_rq); > > > > > > + /* sync clock_pelt_idle with last update */ > > > + if (cfs_rq->nr_running == 0) > > > + update_idle_cfs_rq_clock_pelt(cfs_rq); > > > > I think that if cfs_rq->nr_running == 0 then use cfs rq pelt_idle to update > > idle cfs rq. > > update_blocked_averages() updates all cfs rq to be aligned with now so > we don't need to calculate an estimated now. update_rq_clock(rq) is > called 1st to update the rq->clock and childs > > With only need to save when happened the last update which is done in > update_rq_clock_pelt(rq) for rq->clock_pelt and with > update_idle_cfs_rq_clock_pelt(cfs) for the cfs_rq_clock_pelt
I missed this.
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index a68482d66535..98c81bdb120a 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -3357,6 +3357,29 @@ static inline bool cfs_rq_is_decayed(struct cfs_rq *cfs_rq) return true; } +static inline bool task_se_is_decayed(struct sched_entity *se) +{ + if (se->avg.load_sum) + return false; + + if (se->avg.util_sum) + return false; + + if (se->avg.runnable_sum) + return false; + + /* + * _avg must be null when _sum are null because _avg = _sum / divider + * Make sure that rounding and/or propagation of PELT values never + * break this. + */ + SCHED_WARN_ON(se->avg.load_avg || + se->avg.util_avg || + se->avg.runnable_avg); + + return true; +} + /** * update_tg_load_avg - update the tg's load avg * @cfs_rq: the cfs_rq whose avg changed @@ -3710,6 +3733,77 @@ static inline void add_tg_cfs_propagate(struct cfs_rq *cfs_rq, long runnable_sum #endif /* CONFIG_FAIR_GROUP_SCHED */ +#ifdef CONFIG_NO_HZ_COMMON +static inline void migrate_se_pelt_lag(struct sched_entity *se) +{ + struct cfs_rq *cfs_rq; + struct rq *rq; + bool is_idle; + u64 now; + + /* check if pelt value of the task are fully decayed */ + if (task_se_is_decayed(se)) + return; + + cfs_rq = cfs_rq_of(se); + rq = rq_of(cfs_rq); + + rcu_read_lock(); + is_idle = is_idle_task(rcu_dereference(rq->curr)); + rcu_read_unlock(); + + /* + * The lag estimation comes with a cost we don't want to pay all the + * time. Hence, limiting to the case where the source CPU is idle and + * we know we are at the greatest risk to have an outdated clock. + */ + if (!is_idle) + return; + + /* + * estimated "now" is: + * last_update_time (cfs_clock_pelt when cfs became idle) + + * rq->clock_pelt_idle (rq_clock_pelt when rq became idle) - + * cfs_rq->clock_pelt_idle (rq_clock_pelt when cfs became idle) + * + * PELT idle lag is in fact the time between cfs becoming idle and + * rq becoming idle. + * rq clock lag is the time between rq becoming idle and current time. + * + * when !CFS_BANDWIDTH, cfs_clock_pelt == rq_clock_pelt because there is + * no throttling offset (which can dynamically change) + * so we have: + * last_update_time (rq_clock_pelt when cfs became idle) + + * rq->clock_pelt_idle (rq_clock_pelt when rq became idle) - + * cfs_rq->clock_pelt_idle (rq_clock_pelt when cfs became idle) + * + * which is equals to rq->clock_pelt_idle (rq_clock_pelt when rq became idle) + * This also means that we only need a snapshot of the + * cfs_rq->throttled_clock_pelt_time when cfs became idle and the + * equation becomes like below for CFS_BANDWIDTH + * rq->clock_pelt_idle - snapshot of cfs_rq->throttled_clock_pelt_time + * when entering idle + * + */ +#ifdef CONFIG_CFS_BANDWIDTH + now = u64_u32_load(cfs_rq->throttled_clock_pelt_time); + /* The clock has been stopped for throttling */ + if (now == U64_MAX) + return; + + now = u64_u32_load(rq->clock_pelt_idle) - now; +#else + now = u64_u32_load(rq->clock_pelt_idle); +#endif + now += sched_clock_cpu(cpu_of(rq)) - u64_u32_load(rq->enter_idle); + + __update_load_avg_blocked_se(now, se); +} +#else +static void migrate_se_pelt_lag(struct sched_entity *se) {} +#endif + + /** * update_cfs_rq_load_avg - update the cfs_rq's load/util averages * @now: current time, as per cfs_rq_clock_pelt() @@ -4191,6 +4285,11 @@ static inline bool cfs_rq_is_decayed(struct cfs_rq *cfs_rq) return true; } +static inline bool task_se_is_decayed(struct sched_entity *se) +{ + return true; +} + #define UPDATE_TG 0x0 #define SKIP_AGE_LOAD 0x0 #define DO_ATTACH 0x0 @@ -4465,6 +4564,9 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) */ if ((flags & (DEQUEUE_SAVE | DEQUEUE_MOVE)) != DEQUEUE_SAVE) update_min_vruntime(cfs_rq); + + if (cfs_rq->nr_running == 0) + update_idle_cfs_rq_clock_pelt(cfs_rq); } /* @@ -6982,6 +7084,8 @@ static void detach_entity_cfs_rq(struct sched_entity *se); */ static void migrate_task_rq_fair(struct task_struct *p, int new_cpu) { + struct sched_entity *se = &p->se; + /* * As blocked tasks retain absolute vruntime the migration needs to * deal with this by subtracting the old and adding the new @@ -6989,7 +7093,6 @@ static void migrate_task_rq_fair(struct task_struct *p, int new_cpu) * the task on the new runqueue. */ if (READ_ONCE(p->__state) == TASK_WAKING) { - struct sched_entity *se = &p->se; struct cfs_rq *cfs_rq = cfs_rq_of(se); u64 min_vruntime; @@ -7014,25 +7117,28 @@ static void migrate_task_rq_fair(struct task_struct *p, int new_cpu) * rq->lock and can modify state directly. */ lockdep_assert_rq_held(task_rq(p)); - detach_entity_cfs_rq(&p->se); + detach_entity_cfs_rq(se); } else { + remove_entity_load_avg(&p->se); /* - * We are supposed to update the task to "current" time, then - * its up to date and ready to go to new CPU/cfs_rq. But we - * have difficulty in getting what current time is, so simply - * throw away the out-of-date time. This will result in the - * wakee task is less decayed, but giving the wakee more load - * sounds not bad. + * Here, the task's PELT values have been updated according to + * the current rq's clock. But if that clock hasn't been + * updated in a while, a substantial idle time will be missed, + * leading to an inflation after wake-up on the new rq. + * + * Estimate the missing time from the cfs_rq last_update_time + * and update sched_avg to improve the PELT continuity after + * migration. */ - remove_entity_load_avg(&p->se); + migrate_se_pelt_lag(se); } /* Tell new CPU we are migrated */ - p->se.avg.last_update_time = 0; + se.avg.last_update_time = 0; /* We have migrated, no longer consider this task hot */ - p->se.exec_start = 0; + se.exec_start = 0; update_scan_period(p, new_cpu); } @@ -8198,6 +8304,10 @@ static bool __update_blocked_fair(struct rq *rq, bool *done) if (update_cfs_rq_load_avg(cfs_rq_clock_pelt(cfs_rq), cfs_rq)) { update_tg_load_avg(cfs_rq); + /* sync clock_pelt_idle with last update */ + if (cfs_rq->nr_running == 0) + update_idle_cfs_rq_clock_pelt(cfs_rq); + if (cfs_rq == &rq->cfs) decayed = true; } diff --git a/kernel/sched/pelt.h b/kernel/sched/pelt.h index c336f5f481bc..0a01fe1b6ff4 100644 --- a/kernel/sched/pelt.h +++ b/kernel/sched/pelt.h @@ -61,6 +61,23 @@ static inline void cfs_se_util_change(struct sched_avg *avg) WRITE_ONCE(avg->util_est.enqueued, enqueued); } +static inline u64 rq_clock_pelt(struct rq *rq) +{ + lockdep_assert_rq_held(rq); + assert_clock_updated(rq); + + return rq->clock_pelt - rq->lost_idle_time; +} + +/* The rq is idle, we can sync to clock_task */ +static inline void _update_idle_rq_clock_pelt(struct rq *rq) +{ + rq->clock_pelt = rq_clock_task(rq); + + u64_u32_store(rq->enter_idle, rq_clock(rq)); + u64_u32_store(rq->clock_pelt_idle, rq_clock_pelt(rq)); +} + /* * The clock_pelt scales the time to reflect the effective amount of * computation done during the running delta time but then sync back to @@ -76,8 +93,7 @@ static inline void cfs_se_util_change(struct sched_avg *avg) static inline void update_rq_clock_pelt(struct rq *rq, s64 delta) { if (unlikely(is_idle_task(rq->curr))) { - /* The rq is idle, we can sync to clock_task */ - rq->clock_pelt = rq_clock_task(rq); + _update_idle_rq_clock_pelt(rq); return; } @@ -130,17 +146,24 @@ static inline void update_idle_rq_clock_pelt(struct rq *rq) */ if (util_sum >= divider) rq->lost_idle_time += rq_clock_task(rq) - rq->clock_pelt; -} -static inline u64 rq_clock_pelt(struct rq *rq) -{ - lockdep_assert_rq_held(rq); - assert_clock_updated(rq); - - return rq->clock_pelt - rq->lost_idle_time; + _update_idle_rq_clock_pelt(rq); } #ifdef CONFIG_CFS_BANDWIDTH +static inline void update_idle_cfs_rq_clock_pelt(struct cfs_rq *cfs_rq) +{ + if (unlikely(cfs_rq->throttle_count)) { + u64_u32_store(cfs_rq->clock_pelt_idle, U64_MAX); + u64_u32_store(cfs_rq->throttled_clock_pelt_time, U64_MAX); + } else { + u64_u32_store(cfs_rq->clock_pelt_idle, + rq_clock_pelt(rq_of(cfs_rq))); + u64_u32_store(cfs_rq->throttled_clock_pelt_time, + cfs_rq->throttled_clock_task_time); + } +} + /* rq->task_clock normalized against any time this cfs_rq has spent throttled */ static inline u64 cfs_rq_clock_pelt(struct cfs_rq *cfs_rq) { @@ -150,6 +173,7 @@ static inline u64 cfs_rq_clock_pelt(struct cfs_rq *cfs_rq) return rq_clock_pelt(rq_of(cfs_rq)) - cfs_rq->throttled_clock_task_time; } #else +static inline void update_idle_cfs_rq_clock_pelt(struct cfs_rq *cfs_rq) { } static inline u64 cfs_rq_clock_pelt(struct cfs_rq *cfs_rq) { return rq_clock_pelt(rq_of(cfs_rq)); @@ -204,6 +228,7 @@ update_rq_clock_pelt(struct rq *rq, s64 delta) { } static inline void update_idle_rq_clock_pelt(struct rq *rq) { } +static inline void update_idle_cfs_rq_clock_pelt(struct cfs_rq *cfs_rq) { } #endif diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 8dccb34eb190..3bd77a011676 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -602,6 +602,12 @@ struct cfs_rq { int runtime_enabled; s64 runtime_remaining; + u64 clock_pelt_idle; + u64 throttled_clock_pelt_time; +#ifndef CONFIG_64BIT + u64 clock_pelt_idle_copy; + u64 throttled_clock_pelt_time_copy; +#endif u64 throttled_clock; u64 throttled_clock_task; u64 throttled_clock_task_time; @@ -974,6 +980,12 @@ struct rq { u64 clock_task ____cacheline_aligned; u64 clock_pelt; unsigned long lost_idle_time; + u64 clock_pelt_idle; + u64 enter_idle; +#ifndef CONFIG_64BIT + u64 clock_pelt_idle_copy; + u64 enter_idle_copy; +#endif atomic_t nr_iowait; + u64 clock_pelt_idle; + u64 throttled_clock_pelt_time; +#ifndef CONFIG_64BIT + u64 clock_pelt_idle_copy; + u64 throttled_clock_pelt_time_copy; +#endif u64 throttled_clock; u64 throttled_clock_task; u64 throttled_clock_task_time; @@ -974,6 +980,12 @@ struct rq { u64 clock_task ____cacheline_aligned; u64 clock_pelt; unsigned long lost_idle_time; + u64 clock_pelt_idle; + u64 enter_idle; +#ifndef CONFIG_64BIT + u64 clock_pelt_idle_copy; + u64 enter_idle_copy; +#endif atomic_t nr_iowait;
Thanks, Tao > > > > if (!cfs_rq->nr_running) { > > /* A part. calculation of idle cfs rq */ > > calculate now like in migrate_se_pelt_lag(). > > decay = update_cfs_rq_load_avg(now, cfs_rq); > > } else { > > decay = update_cfs_rq_load_avg(cfs_rq_clock_pelt(cfs_rq), cfs_rq)) > > } > > > > if (decay) { > > update_tg_load_avg(cfs_rq); > > if (cfs_rq == &rq->cfs) > > decayed == ture; > > } > > > > Thanks, > > Tao > > > if (cfs_rq == &rq->cfs) > > > decayed = true; > > > } > > > diff --git a/kernel/sched/pelt.h b/kernel/sched/pelt.h > > > index 4ff2ed4f8fa1..6b39e07b2919 100644 > > > --- a/kernel/sched/pelt.h > > > +++ b/kernel/sched/pelt.h > > > @@ -61,6 +61,23 @@ static inline void cfs_se_util_change(struct sched_avg *avg) > > > WRITE_ONCE(avg->util_est.enqueued, enqueued); > > > } > > > > > > +static inline u64 rq_clock_pelt(struct rq *rq) > > > +{ > > > + lockdep_assert_rq_held(rq); > > > + assert_clock_updated(rq); > > > + > > > + return rq->clock_pelt - rq->lost_idle_time; > > > +} > > > + > > > +/* The rq is idle, we can sync to clock_task */ > > > +static inline void _update_idle_rq_clock_pelt(struct rq *rq) > > > +{ > > > + rq->clock_pelt = rq_clock_task(rq); > > > + > > > + u64_u32_store(rq->enter_idle, rq_clock(rq)); > > > + u64_u32_store(rq->clock_pelt_idle, rq_clock_pelt(rq)); > > > +} > > > + > > > /* > > > * The clock_pelt scales the time to reflect the effective amount of > > > * computation done during the running delta time but then sync back to > > > @@ -76,8 +93,7 @@ static inline void cfs_se_util_change(struct sched_avg *avg) > > > static inline void update_rq_clock_pelt(struct rq *rq, s64 delta) > > > { > > > if (unlikely(is_idle_task(rq->curr))) { > > > - /* The rq is idle, we can sync to clock_task */ > > > - rq->clock_pelt = rq_clock_task(rq); > > > + _update_idle_rq_clock_pelt(rq); > > > return; > > > } > > > > > > @@ -130,17 +146,20 @@ static inline void update_idle_rq_clock_pelt(struct rq *rq) > > > */ > > > if (util_sum >= divider) > > > rq->lost_idle_time += rq_clock_task(rq) - rq->clock_pelt; > > > + > > > + _update_idle_rq_clock_pelt(rq); > > > } > > > > > > -static inline u64 rq_clock_pelt(struct rq *rq) > > > +#ifdef CONFIG_CFS_BANDWIDTH > > > +static inline void update_idle_cfs_rq_clock_pelt(struct cfs_rq *cfs_rq) > > > { > > > - lockdep_assert_rq_held(rq); > > > - assert_clock_updated(rq); > > > - > > > - return rq->clock_pelt - rq->lost_idle_time; > > > + if (unlikely(cfs_rq->throttle_count)) > > > + u64_u32_store(cfs_rq->clock_pelt_idle, U64_MAX); > > > + else > > > + u64_u32_store(cfs_rq->clock_pelt_idle, > > > + rq_clock_pelt(rq_of(cfs_rq))); > > > } > > > > > > -#ifdef CONFIG_CFS_BANDWIDTH > > > /* rq->task_clock normalized against any time this cfs_rq has spent throttled */ > > > static inline u64 cfs_rq_clock_pelt(struct cfs_rq *cfs_rq) > > > { > > > @@ -150,6 +169,7 @@ static inline u64 cfs_rq_clock_pelt(struct cfs_rq *cfs_rq) > > > return rq_clock_pelt(rq_of(cfs_rq)) - cfs_rq->throttled_clock_pelt_time; > > > } > > > #else > > > +static inline void update_idle_cfs_rq_clock_pelt(struct cfs_rq *cfs_rq) { } > > > static inline u64 cfs_rq_clock_pelt(struct cfs_rq *cfs_rq) > > > { > > > return rq_clock_pelt(rq_of(cfs_rq)); > > > @@ -204,6 +224,7 @@ update_rq_clock_pelt(struct rq *rq, s64 delta) { } > > > static inline void > > > update_idle_rq_clock_pelt(struct rq *rq) { } > > > > > > +static inline void update_idle_cfs_rq_clock_pelt(struct cfs_rq *cfs_rq) { } > > > #endif > > > > > > > > > diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h > > > index e2cf6e48b165..07014e8cbae2 100644 > > > --- a/kernel/sched/sched.h > > > +++ b/kernel/sched/sched.h > > > @@ -641,6 +641,10 @@ struct cfs_rq { > > > int runtime_enabled; > > > s64 runtime_remaining; > > > > > > + u64 clock_pelt_idle; > > > +#ifndef CONFIG_64BIT > > > + u64 clock_pelt_idle_copy; > > > +#endif > > > u64 throttled_clock; > > > u64 throttled_clock_pelt; > > > u64 throttled_clock_pelt_time; > > > @@ -1013,6 +1017,12 @@ struct rq { > > > u64 clock_task ____cacheline_aligned; > > > u64 clock_pelt; > > > unsigned long lost_idle_time; > > > + u64 clock_pelt_idle; > > > + u64 enter_idle; > > > +#ifndef CONFIG_64BIT > > > + u64 clock_pelt_idle_copy; > > > + u64 enter_idle_copy; > > > +#endif > > > > > > atomic_t nr_iowait; > > > > > > -- > > > 2.25.1 > > >
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