xref: /linux/kernel/sched/pelt.h (revision bf76f23aa1c178e9115eba17f699fa726aed669b)
1 // SPDX-License-Identifier: GPL-2.0
2 #ifndef _KERNEL_SCHED_PELT_H
3 #define _KERNEL_SCHED_PELT_H
4 #include "sched.h"
5 
6 #include "sched-pelt.h"
7 
8 int __update_load_avg_blocked_se(u64 now, struct sched_entity *se);
9 int __update_load_avg_se(u64 now, struct cfs_rq *cfs_rq, struct sched_entity *se);
10 int __update_load_avg_cfs_rq(u64 now, struct cfs_rq *cfs_rq);
11 int update_rt_rq_load_avg(u64 now, struct rq *rq, int running);
12 int update_dl_rq_load_avg(u64 now, struct rq *rq, int running);
13 bool update_other_load_avgs(struct rq *rq);
14 
15 #ifdef CONFIG_SCHED_HW_PRESSURE
16 int update_hw_load_avg(u64 now, struct rq *rq, u64 capacity);
17 
hw_load_avg(struct rq * rq)18 static inline u64 hw_load_avg(struct rq *rq)
19 {
20 	return READ_ONCE(rq->avg_hw.load_avg);
21 }
22 #else /* !CONFIG_SCHED_HW_PRESSURE: */
23 static inline int
update_hw_load_avg(u64 now,struct rq * rq,u64 capacity)24 update_hw_load_avg(u64 now, struct rq *rq, u64 capacity)
25 {
26 	return 0;
27 }
28 
hw_load_avg(struct rq * rq)29 static inline u64 hw_load_avg(struct rq *rq)
30 {
31 	return 0;
32 }
33 #endif /* !CONFIG_SCHED_HW_PRESSURE */
34 
35 #ifdef CONFIG_HAVE_SCHED_AVG_IRQ
36 int update_irq_load_avg(struct rq *rq, u64 running);
37 #else
38 static inline int
update_irq_load_avg(struct rq * rq,u64 running)39 update_irq_load_avg(struct rq *rq, u64 running)
40 {
41 	return 0;
42 }
43 #endif
44 
45 #define PELT_MIN_DIVIDER	(LOAD_AVG_MAX - 1024)
46 
get_pelt_divider(struct sched_avg * avg)47 static inline u32 get_pelt_divider(struct sched_avg *avg)
48 {
49 	return PELT_MIN_DIVIDER + avg->period_contrib;
50 }
51 
cfs_se_util_change(struct sched_avg * avg)52 static inline void cfs_se_util_change(struct sched_avg *avg)
53 {
54 	unsigned int enqueued;
55 
56 	if (!sched_feat(UTIL_EST))
57 		return;
58 
59 	/* Avoid store if the flag has been already reset */
60 	enqueued = avg->util_est;
61 	if (!(enqueued & UTIL_AVG_UNCHANGED))
62 		return;
63 
64 	/* Reset flag to report util_avg has been updated */
65 	enqueued &= ~UTIL_AVG_UNCHANGED;
66 	WRITE_ONCE(avg->util_est, enqueued);
67 }
68 
rq_clock_pelt(struct rq * rq)69 static inline u64 rq_clock_pelt(struct rq *rq)
70 {
71 	lockdep_assert_rq_held(rq);
72 	assert_clock_updated(rq);
73 
74 	return rq->clock_pelt - rq->lost_idle_time;
75 }
76 
77 /* The rq is idle, we can sync to clock_task */
_update_idle_rq_clock_pelt(struct rq * rq)78 static inline void _update_idle_rq_clock_pelt(struct rq *rq)
79 {
80 	rq->clock_pelt  = rq_clock_task(rq);
81 
82 	u64_u32_store(rq->clock_idle, rq_clock(rq));
83 	/* Paired with smp_rmb in migrate_se_pelt_lag() */
84 	smp_wmb();
85 	u64_u32_store(rq->clock_pelt_idle, rq_clock_pelt(rq));
86 }
87 
88 /*
89  * The clock_pelt scales the time to reflect the effective amount of
90  * computation done during the running delta time but then sync back to
91  * clock_task when rq is idle.
92  *
93  *
94  * absolute time   | 1| 2| 3| 4| 5| 6| 7| 8| 9|10|11|12|13|14|15|16
95  * @ max capacity  ------******---------------******---------------
96  * @ half capacity ------************---------************---------
97  * clock pelt      | 1| 2|    3|    4| 7| 8| 9|   10|   11|14|15|16
98  *
99  */
update_rq_clock_pelt(struct rq * rq,s64 delta)100 static inline void update_rq_clock_pelt(struct rq *rq, s64 delta)
101 {
102 	if (unlikely(is_idle_task(rq->curr))) {
103 		_update_idle_rq_clock_pelt(rq);
104 		return;
105 	}
106 
107 	/*
108 	 * When a rq runs at a lower compute capacity, it will need
109 	 * more time to do the same amount of work than at max
110 	 * capacity. In order to be invariant, we scale the delta to
111 	 * reflect how much work has been really done.
112 	 * Running longer results in stealing idle time that will
113 	 * disturb the load signal compared to max capacity. This
114 	 * stolen idle time will be automatically reflected when the
115 	 * rq will be idle and the clock will be synced with
116 	 * rq_clock_task.
117 	 */
118 
119 	/*
120 	 * Scale the elapsed time to reflect the real amount of
121 	 * computation
122 	 */
123 	delta = cap_scale(delta, arch_scale_cpu_capacity(cpu_of(rq)));
124 	delta = cap_scale(delta, arch_scale_freq_capacity(cpu_of(rq)));
125 
126 	rq->clock_pelt += delta;
127 }
128 
129 /*
130  * When rq becomes idle, we have to check if it has lost idle time
131  * because it was fully busy. A rq is fully used when the /Sum util_sum
132  * is greater or equal to:
133  * (LOAD_AVG_MAX - 1024 + rq->cfs.avg.period_contrib) << SCHED_CAPACITY_SHIFT;
134  * For optimization and computing rounding purpose, we don't take into account
135  * the position in the current window (period_contrib) and we use the higher
136  * bound of util_sum to decide.
137  */
update_idle_rq_clock_pelt(struct rq * rq)138 static inline void update_idle_rq_clock_pelt(struct rq *rq)
139 {
140 	u32 divider = ((LOAD_AVG_MAX - 1024) << SCHED_CAPACITY_SHIFT) - LOAD_AVG_MAX;
141 	u32 util_sum = rq->cfs.avg.util_sum;
142 	util_sum += rq->avg_rt.util_sum;
143 	util_sum += rq->avg_dl.util_sum;
144 
145 	/*
146 	 * Reflecting stolen time makes sense only if the idle
147 	 * phase would be present at max capacity. As soon as the
148 	 * utilization of a rq has reached the maximum value, it is
149 	 * considered as an always running rq without idle time to
150 	 * steal. This potential idle time is considered as lost in
151 	 * this case. We keep track of this lost idle time compare to
152 	 * rq's clock_task.
153 	 */
154 	if (util_sum >= divider)
155 		rq->lost_idle_time += rq_clock_task(rq) - rq->clock_pelt;
156 
157 	_update_idle_rq_clock_pelt(rq);
158 }
159 
160 #ifdef CONFIG_CFS_BANDWIDTH
update_idle_cfs_rq_clock_pelt(struct cfs_rq * cfs_rq)161 static inline void update_idle_cfs_rq_clock_pelt(struct cfs_rq *cfs_rq)
162 {
163 	u64 throttled;
164 
165 	if (unlikely(cfs_rq->throttle_count))
166 		throttled = U64_MAX;
167 	else
168 		throttled = cfs_rq->throttled_clock_pelt_time;
169 
170 	u64_u32_store(cfs_rq->throttled_pelt_idle, throttled);
171 }
172 
173 /* rq->task_clock normalized against any time this cfs_rq has spent throttled */
cfs_rq_clock_pelt(struct cfs_rq * cfs_rq)174 static inline u64 cfs_rq_clock_pelt(struct cfs_rq *cfs_rq)
175 {
176 	if (unlikely(cfs_rq->throttle_count))
177 		return cfs_rq->throttled_clock_pelt - cfs_rq->throttled_clock_pelt_time;
178 
179 	return rq_clock_pelt(rq_of(cfs_rq)) - cfs_rq->throttled_clock_pelt_time;
180 }
181 #else /* !CONFIG_CFS_BANDWIDTH: */
update_idle_cfs_rq_clock_pelt(struct cfs_rq * cfs_rq)182 static inline void update_idle_cfs_rq_clock_pelt(struct cfs_rq *cfs_rq) { }
cfs_rq_clock_pelt(struct cfs_rq * cfs_rq)183 static inline u64 cfs_rq_clock_pelt(struct cfs_rq *cfs_rq)
184 {
185 	return rq_clock_pelt(rq_of(cfs_rq));
186 }
187 #endif /* !CONFIG_CFS_BANDWIDTH */
188 
189 #endif /* _KERNEL_SCHED_PELT_H */
190