kernel/sched/pelt.h

   1 #ifdef CONFIG_SMP
   2 #include "sched-pelt.h"
   3
   4 int __update_load_avg_blocked_se(u64 now, struct sched_entity *se);
   5 int __update_load_avg_se(u64 now, struct cfs_rq *cfs_rq, struct sched_entity *se);
   6 int __update_load_avg_cfs_rq(u64 now, struct cfs_rq *cfs_rq);
   7 int update_rt_rq_load_avg(u64 now, struct rq *rq, int running);
   8 int update_dl_rq_load_avg(u64 now, struct rq *rq, int running);
   9
  10 #ifdef CONFIG_HAVE_SCHED_AVG_IRQ
  11 int update_irq_load_avg(struct rq *rq, u64 running);
  12 #else
  13 static inline int
  14 update_irq_load_avg(struct rq *rq, u64 running)
  15 {
  16         return 0;
  17 }
  18 #endif
  19
  20 /*
  21  * When a task is dequeued, its estimated utilization should not be update if
  22  * its util_avg has not been updated at least once.
  23  * This flag is used to synchronize util_avg updates with util_est updates.
  24  * We map this information into the LSB bit of the utilization saved at
  25  * dequeue time (i.e. util_est.dequeued).
  26  */
  27 #define UTIL_AVG_UNCHANGED 0x1
  28
  29 static inline void cfs_se_util_change(struct sched_avg *avg)
  30 {
  31         unsigned int enqueued;
  32
  33         if (!sched_feat(UTIL_EST))
  34                 return;
  35
  36         /* Avoid store if the flag has been already set */
  37         enqueued = avg->util_est.enqueued;
  38         if (!(enqueued & UTIL_AVG_UNCHANGED))
  39                 return;
  40
  41         /* Reset flag to report util_avg has been updated */
  42         enqueued &= ~UTIL_AVG_UNCHANGED;
  43         WRITE_ONCE(avg->util_est.enqueued, enqueued);
  44 }
  45
  46 /*
  47  * The clock_pelt scales the time to reflect the effective amount of
  48  * computation done during the running delta time but then sync back to
  49  * clock_task when rq is idle.
  50  *
  51  *
  52  * absolute time   | 1| 2| 3| 4| 5| 6| 7| 8| 9|10|11|12|13|14|15|16
  53  * @ max capacity  ------******---------------******---------------
  54  * @ half capacity ------************---------************---------
  55  * clock pelt      | 1| 2|    3|    4| 7| 8| 9|   10|   11|14|15|16
  56  *
  57  */
  58 static inline void update_rq_clock_pelt(struct rq *rq, s64 delta)
  59 {
  60         if (unlikely(is_idle_task(rq->curr))) {
  61                 /* The rq is idle, we can sync to clock_task */
  62                 rq->clock_pelt  = rq_clock_task(rq);
  63                 return;
  64         }
  65
  66         /*
  67          * When a rq runs at a lower compute capacity, it will need
  68          * more time to do the same amount of work than at max
  69          * capacity. In order to be invariant, we scale the delta to
  70          * reflect how much work has been really done.
  71          * Running longer results in stealing idle time that will
  72          * disturb the load signal compared to max capacity. This
  73          * stolen idle time will be automatically reflected when the
  74          * rq will be idle and the clock will be synced with
  75          * rq_clock_task.
  76          */
  77
  78         /*
  79          * Scale the elapsed time to reflect the real amount of
  80          * computation
  81          */
  82         delta = cap_scale(delta, arch_scale_cpu_capacity(cpu_of(rq)));
  83         delta = cap_scale(delta, arch_scale_freq_capacity(cpu_of(rq)));
  84
  85         rq->clock_pelt += delta;
  86 }
  87
  88 /*
  89  * When rq becomes idle, we have to check if it has lost idle time
  90  * because it was fully busy. A rq is fully used when the /Sum util_sum
  91  * is greater or equal to:
  92  * (LOAD_AVG_MAX - 1024 + rq->cfs.avg.period_contrib) << SCHED_CAPACITY_SHIFT;
  93  * For optimization and computing rounding purpose, we don't take into account
  94  * the position in the current window (period_contrib) and we use the higher
  95  * bound of util_sum to decide.
  96  */
  97 static inline void update_idle_rq_clock_pelt(struct rq *rq)
  98 {
  99         u32 divider = ((LOAD_AVG_MAX - 1024) << SCHED_CAPACITY_SHIFT) - LOAD_AVG_MAX;
 100         u32 util_sum = rq->cfs.avg.util_sum;
 101         util_sum += rq->avg_rt.util_sum;
 102         util_sum += rq->avg_dl.util_sum;
 103
 104         /*
 105          * Reflecting stolen time makes sense only if the idle
 106          * phase would be present at max capacity. As soon as the
 107          * utilization of a rq has reached the maximum value, it is
 108          * considered as an always runnig rq without idle time to
 109          * steal. This potential idle time is considered as lost in
 110          * this case. We keep track of this lost idle time compare to
 111          * rq's clock_task.
 112          */
 113         if (util_sum >= divider)
 114                 rq->lost_idle_time += rq_clock_task(rq) - rq->clock_pelt;
 115 }
 116
 117 static inline u64 rq_clock_pelt(struct rq *rq)
 118 {
 119         lockdep_assert_held(&rq->lock);
 120         assert_clock_updated(rq);
 121
 122         return rq->clock_pelt - rq->lost_idle_time;
 123 }
 124
 125 #ifdef CONFIG_CFS_BANDWIDTH
 126 /* rq->task_clock normalized against any time this cfs_rq has spent throttled */
 127 static inline u64 cfs_rq_clock_pelt(struct cfs_rq *cfs_rq)
 128 {
 129         if (unlikely(cfs_rq->throttle_count))
 130                 return cfs_rq->throttled_clock_task - cfs_rq->throttled_clock_task_time;
 131
 132         return rq_clock_pelt(rq_of(cfs_rq)) - cfs_rq->throttled_clock_task_time;
 133 }
 134 #else
 135 static inline u64 cfs_rq_clock_pelt(struct cfs_rq *cfs_rq)
 136 {
 137         return rq_clock_pelt(rq_of(cfs_rq));
 138 }
 139 #endif
 140
 141 #else
 142
 143 static inline int
 144 update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq)
 145 {
 146         return 0;
 147 }
 148
 149 static inline int
 150 update_rt_rq_load_avg(u64 now, struct rq *rq, int running)
 151 {
 152         return 0;
 153 }
 154
 155 static inline int
 156 update_dl_rq_load_avg(u64 now, struct rq *rq, int running)
 157 {
 158         return 0;
 159 }
 160
 161 static inline int
 162 update_irq_load_avg(struct rq *rq, u64 running)
 163 {
 164         return 0;
 165 }
 166
 167 static inline u64 rq_clock_pelt(struct rq *rq)
 168 {
 169         return rq_clock_task(rq);
 170 }
 171
 172 static inline void
 173 update_rq_clock_pelt(struct rq *rq, s64 delta) { }
 174
 175 static inline void
 176 update_idle_rq_clock_pelt(struct rq *rq) { }
 177
 178 #endif
 179
 180