2 * Copyright (c) 2016, The Linux Foundation. All rights reserved.
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 and
6 * only version 2 as published by the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
14 * Window Assisted Load Tracking (WALT) implementation credits:
15 * Srivatsa Vaddagiri, Steve Muckle, Syed Rameez Mustafa, Joonwoo Park,
16 * Pavan Kumar Kondeti, Olav Haugan
18 * 2016-03-06: Integration with EAS/refactoring by Vikram Mulukutla
22 #include <linux/syscore_ops.h>
23 #include <linux/cpufreq.h>
24 #include <trace/events/sched.h>
28 #define WINDOW_STATS_RECENT 0
29 #define WINDOW_STATS_MAX 1
30 #define WINDOW_STATS_MAX_RECENT_AVG 2
31 #define WINDOW_STATS_AVG 3
32 #define WINDOW_STATS_INVALID_POLICY 4
34 #define EXITING_TASK_MARKER 0xdeaddead
36 static __read_mostly unsigned int walt_ravg_hist_size = 5;
37 static __read_mostly unsigned int walt_window_stats_policy =
38 WINDOW_STATS_MAX_RECENT_AVG;
39 static __read_mostly unsigned int walt_account_wait_time = 1;
40 static __read_mostly unsigned int walt_freq_account_wait_time = 0;
41 static __read_mostly unsigned int walt_io_is_busy = 0;
43 unsigned int sysctl_sched_walt_init_task_load_pct = 15;
45 /* 1 -> use PELT based load stats, 0 -> use window-based load stats */
46 unsigned int __read_mostly walt_disabled = 0;
48 static unsigned int max_possible_efficiency = 1024;
49 static unsigned int min_possible_efficiency = 1024;
52 * Maximum possible frequency across all cpus. Task demand and cpu
53 * capacity (cpu_power) metrics are scaled in reference to it.
55 static unsigned int max_possible_freq = 1;
58 * Minimum possible max_freq across all cpus. This will be same as
59 * max_possible_freq on homogeneous systems and could be different from
60 * max_possible_freq on heterogenous systems. min_max_freq is used to derive
61 * capacity (cpu_power) of cpus.
63 static unsigned int min_max_freq = 1;
65 static unsigned int max_load_scale_factor = 1024;
66 static unsigned int max_possible_capacity = 1024;
68 /* Mask of all CPUs that have max_possible_capacity */
69 static cpumask_t mpc_mask = CPU_MASK_ALL;
71 /* Window size (in ns) */
72 __read_mostly unsigned int walt_ravg_window = 20000000;
74 /* Min window size (in ns) = 10ms */
75 #define MIN_SCHED_RAVG_WINDOW 10000000
77 /* Max window size (in ns) = 1s */
78 #define MAX_SCHED_RAVG_WINDOW 1000000000
80 static unsigned int sync_cpu;
81 static ktime_t ktime_last;
82 static bool walt_ktime_suspended;
84 static unsigned int task_load(struct task_struct *p)
86 return p->ravg.demand;
90 walt_inc_cumulative_runnable_avg(struct rq *rq,
91 struct task_struct *p)
93 rq->cumulative_runnable_avg += p->ravg.demand;
97 walt_dec_cumulative_runnable_avg(struct rq *rq,
98 struct task_struct *p)
100 rq->cumulative_runnable_avg -= p->ravg.demand;
101 BUG_ON((s64)rq->cumulative_runnable_avg < 0);
105 fixup_cumulative_runnable_avg(struct rq *rq,
106 struct task_struct *p, s64 task_load_delta)
108 rq->cumulative_runnable_avg += task_load_delta;
109 if ((s64)rq->cumulative_runnable_avg < 0)
110 panic("cra less than zero: tld: %lld, task_load(p) = %u\n",
111 task_load_delta, task_load(p));
114 u64 walt_ktime_clock(void)
116 if (unlikely(walt_ktime_suspended))
117 return ktime_to_ns(ktime_last);
118 return ktime_get_ns();
121 static void walt_resume(void)
123 walt_ktime_suspended = false;
126 static int walt_suspend(void)
128 ktime_last = ktime_get();
129 walt_ktime_suspended = true;
133 static struct syscore_ops walt_syscore_ops = {
134 .resume = walt_resume,
135 .suspend = walt_suspend
138 static int __init walt_init_ops(void)
140 register_syscore_ops(&walt_syscore_ops);
143 late_initcall(walt_init_ops);
145 void walt_inc_cfs_cumulative_runnable_avg(struct cfs_rq *cfs_rq,
146 struct task_struct *p)
148 cfs_rq->cumulative_runnable_avg += p->ravg.demand;
151 void walt_dec_cfs_cumulative_runnable_avg(struct cfs_rq *cfs_rq,
152 struct task_struct *p)
154 cfs_rq->cumulative_runnable_avg -= p->ravg.demand;
157 static int exiting_task(struct task_struct *p)
159 if (p->flags & PF_EXITING) {
160 if (p->ravg.sum_history[0] != EXITING_TASK_MARKER) {
161 p->ravg.sum_history[0] = EXITING_TASK_MARKER;
168 static int __init set_walt_ravg_window(char *str)
170 get_option(&str, &walt_ravg_window);
172 walt_disabled = (walt_ravg_window < MIN_SCHED_RAVG_WINDOW ||
173 walt_ravg_window > MAX_SCHED_RAVG_WINDOW);
177 early_param("walt_ravg_window", set_walt_ravg_window);
180 update_window_start(struct rq *rq, u64 wallclock)
185 delta = wallclock - rq->window_start;
186 /* If the MPM global timer is cleared, set delta as 0 to avoid kernel BUG happening */
189 WARN_ONCE(1, "WALT wallclock appears to have gone backwards or reset\n");
192 if (delta < walt_ravg_window)
195 nr_windows = div64_u64(delta, walt_ravg_window);
196 rq->window_start += (u64)nr_windows * (u64)walt_ravg_window;
199 static u64 scale_exec_time(u64 delta, struct rq *rq)
201 unsigned int cur_freq = rq->cur_freq;
204 if (unlikely(cur_freq > max_possible_freq))
205 cur_freq = rq->max_possible_freq;
208 delta = div64_u64(delta * cur_freq + max_possible_freq - 1,
211 sf = DIV_ROUND_UP(rq->efficiency * 1024, max_possible_efficiency);
219 static int cpu_is_waiting_on_io(struct rq *rq)
221 if (!walt_io_is_busy)
224 return atomic_read(&rq->nr_iowait);
227 void walt_account_irqtime(int cpu, struct task_struct *curr,
228 u64 delta, u64 wallclock)
230 struct rq *rq = cpu_rq(cpu);
231 unsigned long flags, nr_windows;
234 raw_spin_lock_irqsave(&rq->lock, flags);
237 * cputime (wallclock) uses sched_clock so use the same here for
240 delta += sched_clock() - wallclock;
241 cur_jiffies_ts = get_jiffies_64();
243 if (is_idle_task(curr))
244 walt_update_task_ravg(curr, rq, IRQ_UPDATE, walt_ktime_clock(),
247 nr_windows = cur_jiffies_ts - rq->irqload_ts;
250 if (nr_windows < 10) {
251 /* Decay CPU's irqload by 3/4 for each window. */
252 rq->avg_irqload *= (3 * nr_windows);
253 rq->avg_irqload = div64_u64(rq->avg_irqload,
258 rq->avg_irqload += rq->cur_irqload;
262 rq->cur_irqload += delta;
263 rq->irqload_ts = cur_jiffies_ts;
264 raw_spin_unlock_irqrestore(&rq->lock, flags);
268 #define WALT_HIGH_IRQ_TIMEOUT 3
270 u64 walt_irqload(int cpu) {
271 struct rq *rq = cpu_rq(cpu);
273 delta = get_jiffies_64() - rq->irqload_ts;
276 * Current context can be preempted by irq and rq->irqload_ts can be
277 * updated by irq context so that delta can be negative.
278 * But this is okay and we can safely return as this means there
279 * was recent irq occurrence.
282 if (delta < WALT_HIGH_IRQ_TIMEOUT)
283 return rq->avg_irqload;
288 int walt_cpu_high_irqload(int cpu) {
289 return walt_irqload(cpu) >= sysctl_sched_walt_cpu_high_irqload;
292 static int account_busy_for_cpu_time(struct rq *rq, struct task_struct *p,
293 u64 irqtime, int event)
295 if (is_idle_task(p)) {
296 /* TASK_WAKE && TASK_MIGRATE is not possible on idle task! */
297 if (event == PICK_NEXT_TASK)
300 /* PUT_PREV_TASK, TASK_UPDATE && IRQ_UPDATE are left */
301 return irqtime || cpu_is_waiting_on_io(rq);
304 if (event == TASK_WAKE)
307 if (event == PUT_PREV_TASK || event == IRQ_UPDATE ||
308 event == TASK_UPDATE)
311 /* Only TASK_MIGRATE && PICK_NEXT_TASK left */
312 return walt_freq_account_wait_time;
316 * Account cpu activity in its busy time counters (rq->curr/prev_runnable_sum)
318 static void update_cpu_busy_time(struct task_struct *p, struct rq *rq,
319 int event, u64 wallclock, u64 irqtime)
321 int new_window, nr_full_windows = 0;
322 int p_is_curr_task = (p == rq->curr);
323 u64 mark_start = p->ravg.mark_start;
324 u64 window_start = rq->window_start;
325 u32 window_size = walt_ravg_window;
328 new_window = mark_start < window_start;
330 nr_full_windows = div64_u64((window_start - mark_start),
332 if (p->ravg.active_windows < USHRT_MAX)
333 p->ravg.active_windows++;
336 /* Handle per-task window rollover. We don't care about the idle
337 * task or exiting tasks. */
338 if (new_window && !is_idle_task(p) && !exiting_task(p)) {
341 if (!nr_full_windows)
342 curr_window = p->ravg.curr_window;
344 p->ravg.prev_window = curr_window;
345 p->ravg.curr_window = 0;
348 if (!account_busy_for_cpu_time(rq, p, irqtime, event)) {
349 /* account_busy_for_cpu_time() = 0, so no update to the
350 * task's current window needs to be made. This could be
353 * - a wakeup event on a task within the current
354 * window (!new_window below, no action required),
355 * - switching to a new task from idle (PICK_NEXT_TASK)
356 * in a new window where irqtime is 0 and we aren't
362 /* A new window has started. The RQ demand must be rolled
363 * over if p is the current task. */
364 if (p_is_curr_task) {
367 /* p is either idle task or an exiting task */
368 if (!nr_full_windows) {
369 prev_sum = rq->curr_runnable_sum;
372 rq->prev_runnable_sum = prev_sum;
373 rq->curr_runnable_sum = 0;
380 /* account_busy_for_cpu_time() = 1 so busy time needs
381 * to be accounted to the current window. No rollover
382 * since we didn't start a new window. An example of this is
383 * when a task starts execution and then sleeps within the
386 if (!irqtime || !is_idle_task(p) || cpu_is_waiting_on_io(rq))
387 delta = wallclock - mark_start;
390 delta = scale_exec_time(delta, rq);
391 rq->curr_runnable_sum += delta;
392 if (!is_idle_task(p) && !exiting_task(p))
393 p->ravg.curr_window += delta;
398 if (!p_is_curr_task) {
399 /* account_busy_for_cpu_time() = 1 so busy time needs
400 * to be accounted to the current window. A new window
401 * has also started, but p is not the current task, so the
402 * window is not rolled over - just split up and account
403 * as necessary into curr and prev. The window is only
404 * rolled over when a new window is processed for the current
407 * Irqtime can't be accounted by a task that isn't the
408 * currently running task. */
410 if (!nr_full_windows) {
411 /* A full window hasn't elapsed, account partial
412 * contribution to previous completed window. */
413 delta = scale_exec_time(window_start - mark_start, rq);
414 if (!exiting_task(p))
415 p->ravg.prev_window += delta;
417 /* Since at least one full window has elapsed,
418 * the contribution to the previous window is the
419 * full window (window_size). */
420 delta = scale_exec_time(window_size, rq);
421 if (!exiting_task(p))
422 p->ravg.prev_window = delta;
424 rq->prev_runnable_sum += delta;
426 /* Account piece of busy time in the current window. */
427 delta = scale_exec_time(wallclock - window_start, rq);
428 rq->curr_runnable_sum += delta;
429 if (!exiting_task(p))
430 p->ravg.curr_window = delta;
435 if (!irqtime || !is_idle_task(p) || cpu_is_waiting_on_io(rq)) {
436 /* account_busy_for_cpu_time() = 1 so busy time needs
437 * to be accounted to the current window. A new window
438 * has started and p is the current task so rollover is
439 * needed. If any of these three above conditions are true
440 * then this busy time can't be accounted as irqtime.
442 * Busy time for the idle task or exiting tasks need not
445 * An example of this would be a task that starts execution
446 * and then sleeps once a new window has begun. */
448 if (!nr_full_windows) {
449 /* A full window hasn't elapsed, account partial
450 * contribution to previous completed window. */
451 delta = scale_exec_time(window_start - mark_start, rq);
452 if (!is_idle_task(p) && !exiting_task(p))
453 p->ravg.prev_window += delta;
455 delta += rq->curr_runnable_sum;
457 /* Since at least one full window has elapsed,
458 * the contribution to the previous window is the
459 * full window (window_size). */
460 delta = scale_exec_time(window_size, rq);
461 if (!is_idle_task(p) && !exiting_task(p))
462 p->ravg.prev_window = delta;
466 * Rollover for normal runnable sum is done here by overwriting
467 * the values in prev_runnable_sum and curr_runnable_sum.
468 * Rollover for new task runnable sum has completed by previous
471 rq->prev_runnable_sum = delta;
473 /* Account piece of busy time in the current window. */
474 delta = scale_exec_time(wallclock - window_start, rq);
475 rq->curr_runnable_sum = delta;
476 if (!is_idle_task(p) && !exiting_task(p))
477 p->ravg.curr_window = delta;
483 /* account_busy_for_cpu_time() = 1 so busy time needs
484 * to be accounted to the current window. A new window
485 * has started and p is the current task so rollover is
486 * needed. The current task must be the idle task because
487 * irqtime is not accounted for any other task.
489 * Irqtime will be accounted each time we process IRQ activity
490 * after a period of idleness, so we know the IRQ busy time
491 * started at wallclock - irqtime. */
493 BUG_ON(!is_idle_task(p));
494 mark_start = wallclock - irqtime;
496 /* Roll window over. If IRQ busy time was just in the current
497 * window then that is all that need be accounted. */
498 rq->prev_runnable_sum = rq->curr_runnable_sum;
499 if (mark_start > window_start) {
500 rq->curr_runnable_sum = scale_exec_time(irqtime, rq);
504 /* The IRQ busy time spanned multiple windows. Process the
505 * busy time preceding the current window start first. */
506 delta = window_start - mark_start;
507 if (delta > window_size)
509 delta = scale_exec_time(delta, rq);
510 rq->prev_runnable_sum += delta;
512 /* Process the remaining IRQ busy time in the current window. */
513 delta = wallclock - window_start;
514 rq->curr_runnable_sum = scale_exec_time(delta, rq);
522 static int account_busy_for_task_demand(struct task_struct *p, int event)
524 /* No need to bother updating task demand for exiting tasks
525 * or the idle task. */
526 if (exiting_task(p) || is_idle_task(p))
529 /* When a task is waking up it is completing a segment of non-busy
530 * time. Likewise, if wait time is not treated as busy time, then
531 * when a task begins to run or is migrated, it is not running and
532 * is completing a segment of non-busy time. */
533 if (event == TASK_WAKE || (!walt_account_wait_time &&
534 (event == PICK_NEXT_TASK || event == TASK_MIGRATE)))
541 * Called when new window is starting for a task, to record cpu usage over
542 * recently concluded window(s). Normally 'samples' should be 1. It can be > 1
543 * when, say, a real-time task runs without preemption for several windows at a
546 static void update_history(struct rq *rq, struct task_struct *p,
547 u32 runtime, int samples, int event)
549 u32 *hist = &p->ravg.sum_history[0];
551 u32 max = 0, avg, demand;
554 /* Ignore windows where task had no activity */
555 if (!runtime || is_idle_task(p) || exiting_task(p) || !samples)
558 /* Push new 'runtime' value onto stack */
559 widx = walt_ravg_hist_size - 1;
560 ridx = widx - samples;
561 for (; ridx >= 0; --widx, --ridx) {
562 hist[widx] = hist[ridx];
564 if (hist[widx] > max)
568 for (widx = 0; widx < samples && widx < walt_ravg_hist_size; widx++) {
569 hist[widx] = runtime;
571 if (hist[widx] > max)
577 if (walt_window_stats_policy == WINDOW_STATS_RECENT) {
579 } else if (walt_window_stats_policy == WINDOW_STATS_MAX) {
582 avg = div64_u64(sum, walt_ravg_hist_size);
583 if (walt_window_stats_policy == WINDOW_STATS_AVG)
586 demand = max(avg, runtime);
590 * A throttled deadline sched class task gets dequeued without
591 * changing p->on_rq. Since the dequeue decrements hmp stats
592 * avoid decrementing it here again.
594 if (task_on_rq_queued(p) && (!task_has_dl_policy(p) ||
595 !p->dl.dl_throttled))
596 fixup_cumulative_runnable_avg(rq, p, demand);
598 p->ravg.demand = demand;
601 trace_walt_update_history(rq, p, runtime, samples, event);
605 static void add_to_task_demand(struct rq *rq, struct task_struct *p,
608 delta = scale_exec_time(delta, rq);
609 p->ravg.sum += delta;
610 if (unlikely(p->ravg.sum > walt_ravg_window))
611 p->ravg.sum = walt_ravg_window;
615 * Account cpu demand of task and/or update task's cpu demand history
617 * ms = p->ravg.mark_start;
619 * ws = rq->window_start
621 * Three possibilities:
623 * a) Task event is contained within one window.
624 * window_start < mark_start < wallclock
631 * In this case, p->ravg.sum is updated *iff* event is appropriate
632 * (ex: event == PUT_PREV_TASK)
634 * b) Task event spans two windows.
635 * mark_start < window_start < wallclock
640 * -----|-------------------
642 * In this case, p->ravg.sum is updated with (ws - ms) *iff* event
643 * is appropriate, then a new window sample is recorded followed
644 * by p->ravg.sum being set to (wc - ws) *iff* event is appropriate.
646 * c) Task event spans more than two windows.
651 * ---|-------|-------|-------|-------|------
653 * |<------ nr_full_windows ------>|
655 * In this case, p->ravg.sum is updated with (ws_tmp - ms) first *iff*
656 * event is appropriate, window sample of p->ravg.sum is recorded,
657 * 'nr_full_window' samples of window_size is also recorded *iff*
658 * event is appropriate and finally p->ravg.sum is set to (wc - ws)
659 * *iff* event is appropriate.
661 * IMPORTANT : Leave p->ravg.mark_start unchanged, as update_cpu_busy_time()
664 static void update_task_demand(struct task_struct *p, struct rq *rq,
665 int event, u64 wallclock)
667 u64 mark_start = p->ravg.mark_start;
668 u64 delta, window_start = rq->window_start;
669 int new_window, nr_full_windows;
670 u32 window_size = walt_ravg_window;
672 new_window = mark_start < window_start;
673 if (!account_busy_for_task_demand(p, event)) {
675 /* If the time accounted isn't being accounted as
676 * busy time, and a new window started, only the
677 * previous window need be closed out with the
678 * pre-existing demand. Multiple windows may have
679 * elapsed, but since empty windows are dropped,
680 * it is not necessary to account those. */
681 update_history(rq, p, p->ravg.sum, 1, event);
686 /* The simple case - busy time contained within the existing
688 add_to_task_demand(rq, p, wallclock - mark_start);
692 /* Busy time spans at least two windows. Temporarily rewind
693 * window_start to first window boundary after mark_start. */
694 delta = window_start - mark_start;
695 nr_full_windows = div64_u64(delta, window_size);
696 window_start -= (u64)nr_full_windows * (u64)window_size;
698 /* Process (window_start - mark_start) first */
699 add_to_task_demand(rq, p, window_start - mark_start);
701 /* Push new sample(s) into task's demand history */
702 update_history(rq, p, p->ravg.sum, 1, event);
704 update_history(rq, p, scale_exec_time(window_size, rq),
705 nr_full_windows, event);
707 /* Roll window_start back to current to process any remainder
708 * in current window. */
709 window_start += (u64)nr_full_windows * (u64)window_size;
711 /* Process (wallclock - window_start) next */
712 mark_start = window_start;
713 add_to_task_demand(rq, p, wallclock - mark_start);
716 /* Reflect task activity on its demand and cpu's busy time statistics */
717 void walt_update_task_ravg(struct task_struct *p, struct rq *rq,
718 int event, u64 wallclock, u64 irqtime)
720 if (walt_disabled || !rq->window_start)
723 lockdep_assert_held(&rq->lock);
725 update_window_start(rq, wallclock);
727 if (!p->ravg.mark_start)
730 update_task_demand(p, rq, event, wallclock);
731 update_cpu_busy_time(p, rq, event, wallclock, irqtime);
734 trace_walt_update_task_ravg(p, rq, event, wallclock, irqtime);
736 p->ravg.mark_start = wallclock;
739 unsigned long __weak arch_get_cpu_efficiency(int cpu)
741 return SCHED_LOAD_SCALE;
744 void walt_init_cpu_efficiency(void)
747 unsigned int max = 0, min = UINT_MAX;
749 for_each_possible_cpu(i) {
750 efficiency = arch_get_cpu_efficiency(i);
751 cpu_rq(i)->efficiency = efficiency;
753 if (efficiency > max)
755 if (efficiency < min)
760 max_possible_efficiency = max;
763 min_possible_efficiency = min;
766 static void reset_task_stats(struct task_struct *p)
771 sum = EXITING_TASK_MARKER;
773 memset(&p->ravg, 0, sizeof(struct ravg));
774 /* Retain EXITING_TASK marker */
775 p->ravg.sum_history[0] = sum;
778 void walt_mark_task_starting(struct task_struct *p)
781 struct rq *rq = task_rq(p);
783 if (!rq->window_start) {
788 wallclock = walt_ktime_clock();
789 p->ravg.mark_start = wallclock;
792 void walt_set_window_start(struct rq *rq)
794 int cpu = cpu_of(rq);
795 struct rq *sync_rq = cpu_rq(sync_cpu);
797 if (rq->window_start)
800 if (cpu == sync_cpu) {
801 rq->window_start = walt_ktime_clock();
803 raw_spin_unlock(&rq->lock);
804 double_rq_lock(rq, sync_rq);
805 rq->window_start = cpu_rq(sync_cpu)->window_start;
806 rq->curr_runnable_sum = rq->prev_runnable_sum = 0;
807 raw_spin_unlock(&sync_rq->lock);
810 rq->curr->ravg.mark_start = rq->window_start;
813 void walt_migrate_sync_cpu(int cpu)
816 sync_cpu = smp_processor_id();
819 void walt_fixup_busy_time(struct task_struct *p, int new_cpu)
821 struct rq *src_rq = task_rq(p);
822 struct rq *dest_rq = cpu_rq(new_cpu);
825 if (!p->on_rq && p->state != TASK_WAKING)
828 if (exiting_task(p)) {
832 if (p->state == TASK_WAKING)
833 double_rq_lock(src_rq, dest_rq);
835 wallclock = walt_ktime_clock();
837 walt_update_task_ravg(task_rq(p)->curr, task_rq(p),
838 TASK_UPDATE, wallclock, 0);
839 walt_update_task_ravg(dest_rq->curr, dest_rq,
840 TASK_UPDATE, wallclock, 0);
842 walt_update_task_ravg(p, task_rq(p), TASK_MIGRATE, wallclock, 0);
844 if (p->ravg.curr_window) {
845 src_rq->curr_runnable_sum -= p->ravg.curr_window;
846 dest_rq->curr_runnable_sum += p->ravg.curr_window;
849 if (p->ravg.prev_window) {
850 src_rq->prev_runnable_sum -= p->ravg.prev_window;
851 dest_rq->prev_runnable_sum += p->ravg.prev_window;
854 if ((s64)src_rq->prev_runnable_sum < 0) {
855 src_rq->prev_runnable_sum = 0;
858 if ((s64)src_rq->curr_runnable_sum < 0) {
859 src_rq->curr_runnable_sum = 0;
863 trace_walt_migration_update_sum(src_rq, p);
864 trace_walt_migration_update_sum(dest_rq, p);
866 if (p->state == TASK_WAKING)
867 double_rq_unlock(src_rq, dest_rq);
871 * Return 'capacity' of a cpu in reference to "least" efficient cpu, such that
872 * least efficient cpu gets capacity of 1024
874 static unsigned long capacity_scale_cpu_efficiency(int cpu)
876 return (1024 * cpu_rq(cpu)->efficiency) / min_possible_efficiency;
880 * Return 'capacity' of a cpu in reference to cpu with lowest max_freq
881 * (min_max_freq), such that one with lowest max_freq gets capacity of 1024.
883 static unsigned long capacity_scale_cpu_freq(int cpu)
885 return (1024 * cpu_rq(cpu)->max_freq) / min_max_freq;
889 * Return load_scale_factor of a cpu in reference to "most" efficient cpu, so
890 * that "most" efficient cpu gets a load_scale_factor of 1
892 static unsigned long load_scale_cpu_efficiency(int cpu)
894 return DIV_ROUND_UP(1024 * max_possible_efficiency,
895 cpu_rq(cpu)->efficiency);
899 * Return load_scale_factor of a cpu in reference to cpu with best max_freq
900 * (max_possible_freq), so that one with best max_freq gets a load_scale_factor
903 static unsigned long load_scale_cpu_freq(int cpu)
905 return DIV_ROUND_UP(1024 * max_possible_freq, cpu_rq(cpu)->max_freq);
908 static int compute_capacity(int cpu)
912 capacity *= capacity_scale_cpu_efficiency(cpu);
915 capacity *= capacity_scale_cpu_freq(cpu);
921 static int compute_load_scale_factor(int cpu)
923 int load_scale = 1024;
926 * load_scale_factor accounts for the fact that task load
927 * is in reference to "best" performing cpu. Task's load will need to be
928 * scaled (up) by a factor to determine suitability to be placed on a
931 load_scale *= load_scale_cpu_efficiency(cpu);
934 load_scale *= load_scale_cpu_freq(cpu);
940 static int cpufreq_notifier_policy(struct notifier_block *nb,
941 unsigned long val, void *data)
943 struct cpufreq_policy *policy = (struct cpufreq_policy *)data;
944 int i, update_max = 0;
945 u64 highest_mpc = 0, highest_mplsf = 0;
946 const struct cpumask *cpus = policy->related_cpus;
947 unsigned int orig_min_max_freq = min_max_freq;
948 unsigned int orig_max_possible_freq = max_possible_freq;
949 /* Initialized to policy->max in case policy->related_cpus is empty! */
950 unsigned int orig_max_freq = policy->max;
952 if (val != CPUFREQ_NOTIFY)
955 for_each_cpu(i, policy->related_cpus) {
956 cpumask_copy(&cpu_rq(i)->freq_domain_cpumask,
957 policy->related_cpus);
958 orig_max_freq = cpu_rq(i)->max_freq;
959 cpu_rq(i)->min_freq = policy->min;
960 cpu_rq(i)->max_freq = policy->max;
961 cpu_rq(i)->cur_freq = policy->cur;
962 cpu_rq(i)->max_possible_freq = policy->cpuinfo.max_freq;
965 max_possible_freq = max(max_possible_freq, policy->cpuinfo.max_freq);
966 if (min_max_freq == 1)
967 min_max_freq = UINT_MAX;
968 min_max_freq = min(min_max_freq, policy->cpuinfo.max_freq);
969 BUG_ON(!min_max_freq);
970 BUG_ON(!policy->max);
972 /* Changes to policy other than max_freq don't require any updates */
973 if (orig_max_freq == policy->max)
977 * A changed min_max_freq or max_possible_freq (possible during bootup)
978 * needs to trigger re-computation of load_scale_factor and capacity for
979 * all possible cpus (even those offline). It also needs to trigger
980 * re-computation of nr_big_task count on all online cpus.
982 * A changed rq->max_freq otoh needs to trigger re-computation of
983 * load_scale_factor and capacity for just the cluster of cpus involved.
984 * Since small task definition depends on max_load_scale_factor, a
985 * changed load_scale_factor of one cluster could influence
986 * classification of tasks in another cluster. Hence a changed
987 * rq->max_freq will need to trigger re-computation of nr_big_task
988 * count on all online cpus.
990 * While it should be sufficient for nr_big_tasks to be
991 * re-computed for only online cpus, we have inadequate context
992 * information here (in policy notifier) with regard to hotplug-safety
993 * context in which notification is issued. As a result, we can't use
994 * get_online_cpus() here, as it can lead to deadlock. Until cpufreq is
995 * fixed up to issue notification always in hotplug-safe context,
996 * re-compute nr_big_task for all possible cpus.
999 if (orig_min_max_freq != min_max_freq ||
1000 orig_max_possible_freq != max_possible_freq) {
1001 cpus = cpu_possible_mask;
1006 * Changed load_scale_factor can trigger reclassification of tasks as
1007 * big or small. Make this change "atomic" so that tasks are accounted
1008 * properly due to changed load_scale_factor
1010 for_each_cpu(i, cpus) {
1011 struct rq *rq = cpu_rq(i);
1013 rq->capacity = compute_capacity(i);
1014 rq->load_scale_factor = compute_load_scale_factor(i);
1019 mpc = div_u64(((u64) rq->capacity) *
1020 rq->max_possible_freq, rq->max_freq);
1021 rq->max_possible_capacity = (int) mpc;
1023 mplsf = div_u64(((u64) rq->load_scale_factor) *
1024 rq->max_possible_freq, rq->max_freq);
1026 if (mpc > highest_mpc) {
1028 cpumask_clear(&mpc_mask);
1029 cpumask_set_cpu(i, &mpc_mask);
1030 } else if (mpc == highest_mpc) {
1031 cpumask_set_cpu(i, &mpc_mask);
1034 if (mplsf > highest_mplsf)
1035 highest_mplsf = mplsf;
1040 max_possible_capacity = highest_mpc;
1041 max_load_scale_factor = highest_mplsf;
1047 static int cpufreq_notifier_trans(struct notifier_block *nb,
1048 unsigned long val, void *data)
1050 struct cpufreq_freqs *freq = (struct cpufreq_freqs *)data;
1051 unsigned int cpu = freq->cpu, new_freq = freq->new;
1052 unsigned long flags;
1055 if (val != CPUFREQ_POSTCHANGE)
1060 if (cpu_rq(cpu)->cur_freq == new_freq)
1063 for_each_cpu(i, &cpu_rq(cpu)->freq_domain_cpumask) {
1064 struct rq *rq = cpu_rq(i);
1066 raw_spin_lock_irqsave(&rq->lock, flags);
1067 walt_update_task_ravg(rq->curr, rq, TASK_UPDATE,
1068 walt_ktime_clock(), 0);
1069 rq->cur_freq = new_freq;
1070 raw_spin_unlock_irqrestore(&rq->lock, flags);
1076 static struct notifier_block notifier_policy_block = {
1077 .notifier_call = cpufreq_notifier_policy
1080 static struct notifier_block notifier_trans_block = {
1081 .notifier_call = cpufreq_notifier_trans
1084 static int register_sched_callback(void)
1088 ret = cpufreq_register_notifier(¬ifier_policy_block,
1089 CPUFREQ_POLICY_NOTIFIER);
1092 ret = cpufreq_register_notifier(¬ifier_trans_block,
1093 CPUFREQ_TRANSITION_NOTIFIER);
1099 * cpufreq callbacks can be registered at core_initcall or later time.
1100 * Any registration done prior to that is "forgotten" by cpufreq. See
1101 * initialization of variable init_cpufreq_transition_notifier_list_called
1102 * for further information.
1104 core_initcall(register_sched_callback);
1106 void walt_init_new_task_load(struct task_struct *p)
1109 u32 init_load_windows =
1110 div64_u64((u64)sysctl_sched_walt_init_task_load_pct *
1111 (u64)walt_ravg_window, 100);
1112 u32 init_load_pct = current->init_load_pct;
1114 p->init_load_pct = 0;
1115 memset(&p->ravg, 0, sizeof(struct ravg));
1117 if (init_load_pct) {
1118 init_load_windows = div64_u64((u64)init_load_pct *
1119 (u64)walt_ravg_window, 100);
1122 p->ravg.demand = init_load_windows;
1123 for (i = 0; i < RAVG_HIST_SIZE_MAX; ++i)
1124 p->ravg.sum_history[i] = init_load_windows;