| /* |
| * Copyright (c) 2016, The Linux Foundation. All rights reserved. |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 and |
| * only version 2 as published by the Free Software Foundation. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * |
| * Window Assisted Load Tracking (WALT) implementation credits: |
| * Srivatsa Vaddagiri, Steve Muckle, Syed Rameez Mustafa, Joonwoo Park, |
| * Pavan Kumar Kondeti, Olav Haugan |
| * |
| * 2016-03-06: Integration with EAS/refactoring by Vikram Mulukutla |
| * and Todd Kjos |
| */ |
| |
| #include <linux/syscore_ops.h> |
| #include <linux/cpufreq.h> |
| #include <trace/events/sched.h> |
| #include <clocksource/arm_arch_timer.h> |
| #include "sched.h" |
| #include "walt.h" |
| |
| #define WINDOW_STATS_RECENT 0 |
| #define WINDOW_STATS_MAX 1 |
| #define WINDOW_STATS_MAX_RECENT_AVG 2 |
| #define WINDOW_STATS_AVG 3 |
| #define WINDOW_STATS_INVALID_POLICY 4 |
| |
| #define EXITING_TASK_MARKER 0xdeaddead |
| |
| static __read_mostly unsigned int walt_ravg_hist_size = 5; |
| static __read_mostly unsigned int walt_window_stats_policy = |
| WINDOW_STATS_MAX_RECENT_AVG; |
| static __read_mostly unsigned int walt_account_wait_time = 1; |
| static __read_mostly unsigned int walt_freq_account_wait_time = 0; |
| static __read_mostly unsigned int walt_io_is_busy = 0; |
| |
| unsigned int sysctl_sched_walt_init_task_load_pct = 15; |
| |
| /* 1 -> use PELT based load stats, 0 -> use window-based load stats */ |
| unsigned int __read_mostly walt_disabled = 0; |
| |
| static unsigned int max_possible_efficiency = 1024; |
| static unsigned int min_possible_efficiency = 1024; |
| |
| /* |
| * Maximum possible frequency across all cpus. Task demand and cpu |
| * capacity (cpu_power) metrics are scaled in reference to it. |
| */ |
| static unsigned int max_possible_freq = 1; |
| |
| /* |
| * Minimum possible max_freq across all cpus. This will be same as |
| * max_possible_freq on homogeneous systems and could be different from |
| * max_possible_freq on heterogenous systems. min_max_freq is used to derive |
| * capacity (cpu_power) of cpus. |
| */ |
| static unsigned int min_max_freq = 1; |
| |
| static unsigned int max_capacity = 1024; |
| static unsigned int min_capacity = 1024; |
| static unsigned int max_load_scale_factor = 1024; |
| static unsigned int max_possible_capacity = 1024; |
| |
| /* Mask of all CPUs that have max_possible_capacity */ |
| static cpumask_t mpc_mask = CPU_MASK_ALL; |
| |
| /* Window size (in ns) */ |
| __read_mostly unsigned int walt_ravg_window = 20000000; |
| |
| /* Min window size (in ns) = 10ms */ |
| #ifdef CONFIG_HZ_300 |
| /* |
| * Tick interval becomes to 3333333 due to |
| * rounding error when HZ=300. |
| */ |
| #define MIN_SCHED_RAVG_WINDOW (3333333 * 6) |
| #else |
| #define MIN_SCHED_RAVG_WINDOW 10000000 |
| #endif |
| |
| /* Max window size (in ns) = 1s */ |
| #define MAX_SCHED_RAVG_WINDOW 1000000000 |
| |
| static unsigned int sync_cpu; |
| static ktime_t ktime_last; |
| static bool walt_ktime_suspended; |
| |
| static unsigned int task_load(struct task_struct *p) |
| { |
| return p->ravg.demand; |
| } |
| |
| void |
| walt_inc_cumulative_runnable_avg(struct rq *rq, |
| struct task_struct *p) |
| { |
| rq->cumulative_runnable_avg += p->ravg.demand; |
| } |
| |
| void |
| walt_dec_cumulative_runnable_avg(struct rq *rq, |
| struct task_struct *p) |
| { |
| rq->cumulative_runnable_avg -= p->ravg.demand; |
| BUG_ON((s64)rq->cumulative_runnable_avg < 0); |
| } |
| |
| static void |
| fixup_cumulative_runnable_avg(struct rq *rq, |
| struct task_struct *p, s64 task_load_delta) |
| { |
| rq->cumulative_runnable_avg += task_load_delta; |
| if ((s64)rq->cumulative_runnable_avg < 0) |
| panic("cra less than zero: tld: %lld, task_load(p) = %u\n", |
| task_load_delta, task_load(p)); |
| } |
| |
| u64 walt_ktime_clock(void) |
| { |
| if (unlikely(walt_ktime_suspended)) |
| return ktime_to_ns(ktime_last); |
| return ktime_get_ns(); |
| } |
| |
| static void walt_resume(void) |
| { |
| walt_ktime_suspended = false; |
| } |
| |
| static int walt_suspend(void) |
| { |
| ktime_last = ktime_get(); |
| walt_ktime_suspended = true; |
| return 0; |
| } |
| |
| static struct syscore_ops walt_syscore_ops = { |
| .resume = walt_resume, |
| .suspend = walt_suspend |
| }; |
| |
| static int __init walt_init_ops(void) |
| { |
| register_syscore_ops(&walt_syscore_ops); |
| return 0; |
| } |
| late_initcall(walt_init_ops); |
| |
| void walt_inc_cfs_cumulative_runnable_avg(struct cfs_rq *cfs_rq, |
| struct task_struct *p) |
| { |
| cfs_rq->cumulative_runnable_avg += p->ravg.demand; |
| } |
| |
| void walt_dec_cfs_cumulative_runnable_avg(struct cfs_rq *cfs_rq, |
| struct task_struct *p) |
| { |
| cfs_rq->cumulative_runnable_avg -= p->ravg.demand; |
| } |
| |
| static int exiting_task(struct task_struct *p) |
| { |
| if (p->flags & PF_EXITING) { |
| if (p->ravg.sum_history[0] != EXITING_TASK_MARKER) { |
| p->ravg.sum_history[0] = EXITING_TASK_MARKER; |
| } |
| return 1; |
| } |
| return 0; |
| } |
| |
| static int __init set_walt_ravg_window(char *str) |
| { |
| get_option(&str, &walt_ravg_window); |
| |
| walt_disabled = (walt_ravg_window < MIN_SCHED_RAVG_WINDOW || |
| walt_ravg_window > MAX_SCHED_RAVG_WINDOW); |
| return 0; |
| } |
| |
| early_param("walt_ravg_window", set_walt_ravg_window); |
| |
| static void |
| update_window_start(struct rq *rq, u64 wallclock) |
| { |
| s64 delta; |
| int nr_windows; |
| |
| delta = wallclock - rq->window_start; |
| /* If the MPM global timer is cleared, set delta as 0 to avoid kernel BUG happening */ |
| if (delta < 0) { |
| if (arch_timer_read_counter() == 0) |
| delta = 0; |
| else |
| BUG_ON(1); |
| } |
| |
| if (delta < walt_ravg_window) |
| return; |
| |
| nr_windows = div64_u64(delta, walt_ravg_window); |
| rq->window_start += (u64)nr_windows * (u64)walt_ravg_window; |
| } |
| |
| static u64 scale_exec_time(u64 delta, struct rq *rq) |
| { |
| unsigned int cur_freq = rq->cur_freq; |
| int sf; |
| |
| if (unlikely(cur_freq > max_possible_freq)) |
| cur_freq = rq->max_possible_freq; |
| |
| /* round up div64 */ |
| delta = div64_u64(delta * cur_freq + max_possible_freq - 1, |
| max_possible_freq); |
| |
| sf = DIV_ROUND_UP(rq->efficiency * 1024, max_possible_efficiency); |
| |
| delta *= sf; |
| delta >>= 10; |
| |
| return delta; |
| } |
| |
| static int cpu_is_waiting_on_io(struct rq *rq) |
| { |
| if (!walt_io_is_busy) |
| return 0; |
| |
| return atomic_read(&rq->nr_iowait); |
| } |
| |
| void walt_account_irqtime(int cpu, struct task_struct *curr, |
| u64 delta, u64 wallclock) |
| { |
| struct rq *rq = cpu_rq(cpu); |
| unsigned long flags, nr_windows; |
| u64 cur_jiffies_ts; |
| |
| raw_spin_lock_irqsave(&rq->lock, flags); |
| |
| /* |
| * cputime (wallclock) uses sched_clock so use the same here for |
| * consistency. |
| */ |
| delta += sched_clock() - wallclock; |
| cur_jiffies_ts = get_jiffies_64(); |
| |
| if (is_idle_task(curr)) |
| walt_update_task_ravg(curr, rq, IRQ_UPDATE, walt_ktime_clock(), |
| delta); |
| |
| nr_windows = cur_jiffies_ts - rq->irqload_ts; |
| |
| if (nr_windows) { |
| if (nr_windows < 10) { |
| /* Decay CPU's irqload by 3/4 for each window. */ |
| rq->avg_irqload *= (3 * nr_windows); |
| rq->avg_irqload = div64_u64(rq->avg_irqload, |
| 4 * nr_windows); |
| } else { |
| rq->avg_irqload = 0; |
| } |
| rq->avg_irqload += rq->cur_irqload; |
| rq->cur_irqload = 0; |
| } |
| |
| rq->cur_irqload += delta; |
| rq->irqload_ts = cur_jiffies_ts; |
| raw_spin_unlock_irqrestore(&rq->lock, flags); |
| } |
| |
| |
| #define WALT_HIGH_IRQ_TIMEOUT 3 |
| |
| u64 walt_irqload(int cpu) { |
| struct rq *rq = cpu_rq(cpu); |
| s64 delta; |
| delta = get_jiffies_64() - rq->irqload_ts; |
| |
| /* |
| * Current context can be preempted by irq and rq->irqload_ts can be |
| * updated by irq context so that delta can be negative. |
| * But this is okay and we can safely return as this means there |
| * was recent irq occurrence. |
| */ |
| |
| if (delta < WALT_HIGH_IRQ_TIMEOUT) |
| return rq->avg_irqload; |
| else |
| return 0; |
| } |
| |
| int walt_cpu_high_irqload(int cpu) { |
| return walt_irqload(cpu) >= sysctl_sched_walt_cpu_high_irqload; |
| } |
| |
| static int account_busy_for_cpu_time(struct rq *rq, struct task_struct *p, |
| u64 irqtime, int event) |
| { |
| if (is_idle_task(p)) { |
| /* TASK_WAKE && TASK_MIGRATE is not possible on idle task! */ |
| if (event == PICK_NEXT_TASK) |
| return 0; |
| |
| /* PUT_PREV_TASK, TASK_UPDATE && IRQ_UPDATE are left */ |
| return irqtime || cpu_is_waiting_on_io(rq); |
| } |
| |
| if (event == TASK_WAKE) |
| return 0; |
| |
| if (event == PUT_PREV_TASK || event == IRQ_UPDATE || |
| event == TASK_UPDATE) |
| return 1; |
| |
| /* Only TASK_MIGRATE && PICK_NEXT_TASK left */ |
| return walt_freq_account_wait_time; |
| } |
| |
| /* |
| * Account cpu activity in its busy time counters (rq->curr/prev_runnable_sum) |
| */ |
| static void update_cpu_busy_time(struct task_struct *p, struct rq *rq, |
| int event, u64 wallclock, u64 irqtime) |
| { |
| int new_window, nr_full_windows = 0; |
| int p_is_curr_task = (p == rq->curr); |
| u64 mark_start = p->ravg.mark_start; |
| u64 window_start = rq->window_start; |
| u32 window_size = walt_ravg_window; |
| u64 delta; |
| |
| new_window = mark_start < window_start; |
| if (new_window) { |
| nr_full_windows = div64_u64((window_start - mark_start), |
| window_size); |
| if (p->ravg.active_windows < USHRT_MAX) |
| p->ravg.active_windows++; |
| } |
| |
| /* Handle per-task window rollover. We don't care about the idle |
| * task or exiting tasks. */ |
| if (new_window && !is_idle_task(p) && !exiting_task(p)) { |
| u32 curr_window = 0; |
| |
| if (!nr_full_windows) |
| curr_window = p->ravg.curr_window; |
| |
| p->ravg.prev_window = curr_window; |
| p->ravg.curr_window = 0; |
| } |
| |
| if (!account_busy_for_cpu_time(rq, p, irqtime, event)) { |
| /* account_busy_for_cpu_time() = 0, so no update to the |
| * task's current window needs to be made. This could be |
| * for example |
| * |
| * - a wakeup event on a task within the current |
| * window (!new_window below, no action required), |
| * - switching to a new task from idle (PICK_NEXT_TASK) |
| * in a new window where irqtime is 0 and we aren't |
| * waiting on IO */ |
| |
| if (!new_window) |
| return; |
| |
| /* A new window has started. The RQ demand must be rolled |
| * over if p is the current task. */ |
| if (p_is_curr_task) { |
| u64 prev_sum = 0; |
| |
| /* p is either idle task or an exiting task */ |
| if (!nr_full_windows) { |
| prev_sum = rq->curr_runnable_sum; |
| } |
| |
| rq->prev_runnable_sum = prev_sum; |
| rq->curr_runnable_sum = 0; |
| } |
| |
| return; |
| } |
| |
| if (!new_window) { |
| /* account_busy_for_cpu_time() = 1 so busy time needs |
| * to be accounted to the current window. No rollover |
| * since we didn't start a new window. An example of this is |
| * when a task starts execution and then sleeps within the |
| * same window. */ |
| |
| if (!irqtime || !is_idle_task(p) || cpu_is_waiting_on_io(rq)) |
| delta = wallclock - mark_start; |
| else |
| delta = irqtime; |
| delta = scale_exec_time(delta, rq); |
| rq->curr_runnable_sum += delta; |
| if (!is_idle_task(p) && !exiting_task(p)) |
| p->ravg.curr_window += delta; |
| |
| return; |
| } |
| |
| if (!p_is_curr_task) { |
| /* account_busy_for_cpu_time() = 1 so busy time needs |
| * to be accounted to the current window. A new window |
| * has also started, but p is not the current task, so the |
| * window is not rolled over - just split up and account |
| * as necessary into curr and prev. The window is only |
| * rolled over when a new window is processed for the current |
| * task. |
| * |
| * Irqtime can't be accounted by a task that isn't the |
| * currently running task. */ |
| |
| if (!nr_full_windows) { |
| /* A full window hasn't elapsed, account partial |
| * contribution to previous completed window. */ |
| delta = scale_exec_time(window_start - mark_start, rq); |
| if (!exiting_task(p)) |
| p->ravg.prev_window += delta; |
| } else { |
| /* Since at least one full window has elapsed, |
| * the contribution to the previous window is the |
| * full window (window_size). */ |
| delta = scale_exec_time(window_size, rq); |
| if (!exiting_task(p)) |
| p->ravg.prev_window = delta; |
| } |
| rq->prev_runnable_sum += delta; |
| |
| /* Account piece of busy time in the current window. */ |
| delta = scale_exec_time(wallclock - window_start, rq); |
| rq->curr_runnable_sum += delta; |
| if (!exiting_task(p)) |
| p->ravg.curr_window = delta; |
| |
| return; |
| } |
| |
| if (!irqtime || !is_idle_task(p) || cpu_is_waiting_on_io(rq)) { |
| /* account_busy_for_cpu_time() = 1 so busy time needs |
| * to be accounted to the current window. A new window |
| * has started and p is the current task so rollover is |
| * needed. If any of these three above conditions are true |
| * then this busy time can't be accounted as irqtime. |
| * |
| * Busy time for the idle task or exiting tasks need not |
| * be accounted. |
| * |
| * An example of this would be a task that starts execution |
| * and then sleeps once a new window has begun. */ |
| |
| if (!nr_full_windows) { |
| /* A full window hasn't elapsed, account partial |
| * contribution to previous completed window. */ |
| delta = scale_exec_time(window_start - mark_start, rq); |
| if (!is_idle_task(p) && !exiting_task(p)) |
| p->ravg.prev_window += delta; |
| |
| delta += rq->curr_runnable_sum; |
| } else { |
| /* Since at least one full window has elapsed, |
| * the contribution to the previous window is the |
| * full window (window_size). */ |
| delta = scale_exec_time(window_size, rq); |
| if (!is_idle_task(p) && !exiting_task(p)) |
| p->ravg.prev_window = delta; |
| |
| } |
| /* |
| * Rollover for normal runnable sum is done here by overwriting |
| * the values in prev_runnable_sum and curr_runnable_sum. |
| * Rollover for new task runnable sum has completed by previous |
| * if-else statement. |
| */ |
| rq->prev_runnable_sum = delta; |
| |
| /* Account piece of busy time in the current window. */ |
| delta = scale_exec_time(wallclock - window_start, rq); |
| rq->curr_runnable_sum = delta; |
| if (!is_idle_task(p) && !exiting_task(p)) |
| p->ravg.curr_window = delta; |
| |
| return; |
| } |
| |
| if (irqtime) { |
| /* account_busy_for_cpu_time() = 1 so busy time needs |
| * to be accounted to the current window. A new window |
| * has started and p is the current task so rollover is |
| * needed. The current task must be the idle task because |
| * irqtime is not accounted for any other task. |
| * |
| * Irqtime will be accounted each time we process IRQ activity |
| * after a period of idleness, so we know the IRQ busy time |
| * started at wallclock - irqtime. */ |
| |
| BUG_ON(!is_idle_task(p)); |
| mark_start = wallclock - irqtime; |
| |
| /* Roll window over. If IRQ busy time was just in the current |
| * window then that is all that need be accounted. */ |
| rq->prev_runnable_sum = rq->curr_runnable_sum; |
| if (mark_start > window_start) { |
| rq->curr_runnable_sum = scale_exec_time(irqtime, rq); |
| return; |
| } |
| |
| /* The IRQ busy time spanned multiple windows. Process the |
| * busy time preceding the current window start first. */ |
| delta = window_start - mark_start; |
| if (delta > window_size) |
| delta = window_size; |
| delta = scale_exec_time(delta, rq); |
| rq->prev_runnable_sum += delta; |
| |
| /* Process the remaining IRQ busy time in the current window. */ |
| delta = wallclock - window_start; |
| rq->curr_runnable_sum = scale_exec_time(delta, rq); |
| |
| return; |
| } |
| |
| BUG(); |
| } |
| |
| static int account_busy_for_task_demand(struct task_struct *p, int event) |
| { |
| /* No need to bother updating task demand for exiting tasks |
| * or the idle task. */ |
| if (exiting_task(p) || is_idle_task(p)) |
| return 0; |
| |
| /* When a task is waking up it is completing a segment of non-busy |
| * time. Likewise, if wait time is not treated as busy time, then |
| * when a task begins to run or is migrated, it is not running and |
| * is completing a segment of non-busy time. */ |
| if (event == TASK_WAKE || (!walt_account_wait_time && |
| (event == PICK_NEXT_TASK || event == TASK_MIGRATE))) |
| return 0; |
| |
| return 1; |
| } |
| |
| /* |
| * Called when new window is starting for a task, to record cpu usage over |
| * recently concluded window(s). Normally 'samples' should be 1. It can be > 1 |
| * when, say, a real-time task runs without preemption for several windows at a |
| * stretch. |
| */ |
| static void update_history(struct rq *rq, struct task_struct *p, |
| u32 runtime, int samples, int event) |
| { |
| u32 *hist = &p->ravg.sum_history[0]; |
| int ridx, widx; |
| u32 max = 0, avg, demand; |
| u64 sum = 0; |
| |
| /* Ignore windows where task had no activity */ |
| if (!runtime || is_idle_task(p) || exiting_task(p) || !samples) |
| goto done; |
| |
| /* Push new 'runtime' value onto stack */ |
| widx = walt_ravg_hist_size - 1; |
| ridx = widx - samples; |
| for (; ridx >= 0; --widx, --ridx) { |
| hist[widx] = hist[ridx]; |
| sum += hist[widx]; |
| if (hist[widx] > max) |
| max = hist[widx]; |
| } |
| |
| for (widx = 0; widx < samples && widx < walt_ravg_hist_size; widx++) { |
| hist[widx] = runtime; |
| sum += hist[widx]; |
| if (hist[widx] > max) |
| max = hist[widx]; |
| } |
| |
| p->ravg.sum = 0; |
| |
| if (walt_window_stats_policy == WINDOW_STATS_RECENT) { |
| demand = runtime; |
| } else if (walt_window_stats_policy == WINDOW_STATS_MAX) { |
| demand = max; |
| } else { |
| avg = div64_u64(sum, walt_ravg_hist_size); |
| if (walt_window_stats_policy == WINDOW_STATS_AVG) |
| demand = avg; |
| else |
| demand = max(avg, runtime); |
| } |
| |
| /* |
| * A throttled deadline sched class task gets dequeued without |
| * changing p->on_rq. Since the dequeue decrements hmp stats |
| * avoid decrementing it here again. |
| */ |
| if (task_on_rq_queued(p) && (!task_has_dl_policy(p) || |
| !p->dl.dl_throttled)) |
| fixup_cumulative_runnable_avg(rq, p, demand); |
| |
| p->ravg.demand = demand; |
| |
| done: |
| trace_walt_update_history(rq, p, runtime, samples, event); |
| return; |
| } |
| |
| static void add_to_task_demand(struct rq *rq, struct task_struct *p, |
| u64 delta) |
| { |
| delta = scale_exec_time(delta, rq); |
| p->ravg.sum += delta; |
| if (unlikely(p->ravg.sum > walt_ravg_window)) |
| p->ravg.sum = walt_ravg_window; |
| } |
| |
| /* |
| * Account cpu demand of task and/or update task's cpu demand history |
| * |
| * ms = p->ravg.mark_start; |
| * wc = wallclock |
| * ws = rq->window_start |
| * |
| * Three possibilities: |
| * |
| * a) Task event is contained within one window. |
| * window_start < mark_start < wallclock |
| * |
| * ws ms wc |
| * | | | |
| * V V V |
| * |---------------| |
| * |
| * In this case, p->ravg.sum is updated *iff* event is appropriate |
| * (ex: event == PUT_PREV_TASK) |
| * |
| * b) Task event spans two windows. |
| * mark_start < window_start < wallclock |
| * |
| * ms ws wc |
| * | | | |
| * V V V |
| * -----|------------------- |
| * |
| * In this case, p->ravg.sum is updated with (ws - ms) *iff* event |
| * is appropriate, then a new window sample is recorded followed |
| * by p->ravg.sum being set to (wc - ws) *iff* event is appropriate. |
| * |
| * c) Task event spans more than two windows. |
| * |
| * ms ws_tmp ws wc |
| * | | | | |
| * V V V V |
| * ---|-------|-------|-------|-------|------ |
| * | | |
| * |<------ nr_full_windows ------>| |
| * |
| * In this case, p->ravg.sum is updated with (ws_tmp - ms) first *iff* |
| * event is appropriate, window sample of p->ravg.sum is recorded, |
| * 'nr_full_window' samples of window_size is also recorded *iff* |
| * event is appropriate and finally p->ravg.sum is set to (wc - ws) |
| * *iff* event is appropriate. |
| * |
| * IMPORTANT : Leave p->ravg.mark_start unchanged, as update_cpu_busy_time() |
| * depends on it! |
| */ |
| static void update_task_demand(struct task_struct *p, struct rq *rq, |
| int event, u64 wallclock) |
| { |
| u64 mark_start = p->ravg.mark_start; |
| u64 delta, window_start = rq->window_start; |
| int new_window, nr_full_windows; |
| u32 window_size = walt_ravg_window; |
| |
| new_window = mark_start < window_start; |
| if (!account_busy_for_task_demand(p, event)) { |
| if (new_window) |
| /* If the time accounted isn't being accounted as |
| * busy time, and a new window started, only the |
| * previous window need be closed out with the |
| * pre-existing demand. Multiple windows may have |
| * elapsed, but since empty windows are dropped, |
| * it is not necessary to account those. */ |
| update_history(rq, p, p->ravg.sum, 1, event); |
| return; |
| } |
| |
| if (!new_window) { |
| /* The simple case - busy time contained within the existing |
| * window. */ |
| add_to_task_demand(rq, p, wallclock - mark_start); |
| return; |
| } |
| |
| /* Busy time spans at least two windows. Temporarily rewind |
| * window_start to first window boundary after mark_start. */ |
| delta = window_start - mark_start; |
| nr_full_windows = div64_u64(delta, window_size); |
| window_start -= (u64)nr_full_windows * (u64)window_size; |
| |
| /* Process (window_start - mark_start) first */ |
| add_to_task_demand(rq, p, window_start - mark_start); |
| |
| /* Push new sample(s) into task's demand history */ |
| update_history(rq, p, p->ravg.sum, 1, event); |
| if (nr_full_windows) |
| update_history(rq, p, scale_exec_time(window_size, rq), |
| nr_full_windows, event); |
| |
| /* Roll window_start back to current to process any remainder |
| * in current window. */ |
| window_start += (u64)nr_full_windows * (u64)window_size; |
| |
| /* Process (wallclock - window_start) next */ |
| mark_start = window_start; |
| add_to_task_demand(rq, p, wallclock - mark_start); |
| } |
| |
| /* Reflect task activity on its demand and cpu's busy time statistics */ |
| void walt_update_task_ravg(struct task_struct *p, struct rq *rq, |
| int event, u64 wallclock, u64 irqtime) |
| { |
| if (walt_disabled || !rq->window_start) |
| return; |
| |
| lockdep_assert_held(&rq->lock); |
| |
| update_window_start(rq, wallclock); |
| |
| if (!p->ravg.mark_start) |
| goto done; |
| |
| update_task_demand(p, rq, event, wallclock); |
| update_cpu_busy_time(p, rq, event, wallclock, irqtime); |
| |
| done: |
| trace_walt_update_task_ravg(p, rq, event, wallclock, irqtime); |
| |
| p->ravg.mark_start = wallclock; |
| } |
| |
| unsigned long __weak arch_get_cpu_efficiency(int cpu) |
| { |
| return SCHED_LOAD_SCALE; |
| } |
| |
| void walt_init_cpu_efficiency(void) |
| { |
| int i, efficiency; |
| unsigned int max = 0, min = UINT_MAX; |
| |
| for_each_possible_cpu(i) { |
| efficiency = arch_get_cpu_efficiency(i); |
| cpu_rq(i)->efficiency = efficiency; |
| |
| if (efficiency > max) |
| max = efficiency; |
| if (efficiency < min) |
| min = efficiency; |
| } |
| |
| if (max) |
| max_possible_efficiency = max; |
| |
| if (min) |
| min_possible_efficiency = min; |
| } |
| |
| static void reset_task_stats(struct task_struct *p) |
| { |
| u32 sum = 0; |
| |
| if (exiting_task(p)) |
| sum = EXITING_TASK_MARKER; |
| |
| memset(&p->ravg, 0, sizeof(struct ravg)); |
| /* Retain EXITING_TASK marker */ |
| p->ravg.sum_history[0] = sum; |
| } |
| |
| void walt_mark_task_starting(struct task_struct *p) |
| { |
| u64 wallclock; |
| struct rq *rq = task_rq(p); |
| |
| if (!rq->window_start) { |
| reset_task_stats(p); |
| return; |
| } |
| |
| wallclock = walt_ktime_clock(); |
| p->ravg.mark_start = wallclock; |
| } |
| |
| void walt_set_window_start(struct rq *rq) |
| { |
| int cpu = cpu_of(rq); |
| struct rq *sync_rq = cpu_rq(sync_cpu); |
| |
| if (rq->window_start) |
| return; |
| |
| if (cpu == sync_cpu) { |
| rq->window_start = walt_ktime_clock(); |
| } else { |
| raw_spin_unlock(&rq->lock); |
| double_rq_lock(rq, sync_rq); |
| rq->window_start = cpu_rq(sync_cpu)->window_start; |
| rq->curr_runnable_sum = rq->prev_runnable_sum = 0; |
| raw_spin_unlock(&sync_rq->lock); |
| } |
| |
| rq->curr->ravg.mark_start = rq->window_start; |
| } |
| |
| void walt_migrate_sync_cpu(int cpu) |
| { |
| if (cpu == sync_cpu) |
| sync_cpu = smp_processor_id(); |
| } |
| |
| void walt_fixup_busy_time(struct task_struct *p, int new_cpu) |
| { |
| struct rq *src_rq = task_rq(p); |
| struct rq *dest_rq = cpu_rq(new_cpu); |
| u64 wallclock; |
| |
| if (!p->on_rq && p->state != TASK_WAKING) |
| return; |
| |
| if (exiting_task(p)) { |
| return; |
| } |
| |
| if (p->state == TASK_WAKING) |
| double_rq_lock(src_rq, dest_rq); |
| |
| wallclock = walt_ktime_clock(); |
| |
| walt_update_task_ravg(task_rq(p)->curr, task_rq(p), |
| TASK_UPDATE, wallclock, 0); |
| walt_update_task_ravg(dest_rq->curr, dest_rq, |
| TASK_UPDATE, wallclock, 0); |
| |
| walt_update_task_ravg(p, task_rq(p), TASK_MIGRATE, wallclock, 0); |
| |
| if (p->ravg.curr_window) { |
| src_rq->curr_runnable_sum -= p->ravg.curr_window; |
| dest_rq->curr_runnable_sum += p->ravg.curr_window; |
| } |
| |
| if (p->ravg.prev_window) { |
| src_rq->prev_runnable_sum -= p->ravg.prev_window; |
| dest_rq->prev_runnable_sum += p->ravg.prev_window; |
| } |
| |
| if ((s64)src_rq->prev_runnable_sum < 0) { |
| src_rq->prev_runnable_sum = 0; |
| WARN_ON(1); |
| } |
| if ((s64)src_rq->curr_runnable_sum < 0) { |
| src_rq->curr_runnable_sum = 0; |
| WARN_ON(1); |
| } |
| |
| trace_walt_migration_update_sum(src_rq, p); |
| trace_walt_migration_update_sum(dest_rq, p); |
| |
| if (p->state == TASK_WAKING) |
| double_rq_unlock(src_rq, dest_rq); |
| } |
| |
| /* Keep track of max/min capacity possible across CPUs "currently" */ |
| static void __update_min_max_capacity(void) |
| { |
| int i; |
| int max = 0, min = INT_MAX; |
| |
| for_each_online_cpu(i) { |
| if (cpu_rq(i)->capacity > max) |
| max = cpu_rq(i)->capacity; |
| if (cpu_rq(i)->capacity < min) |
| min = cpu_rq(i)->capacity; |
| } |
| |
| max_capacity = max; |
| min_capacity = min; |
| } |
| |
| static void update_min_max_capacity(void) |
| { |
| unsigned long flags; |
| int i; |
| |
| local_irq_save(flags); |
| for_each_possible_cpu(i) |
| raw_spin_lock(&cpu_rq(i)->lock); |
| |
| __update_min_max_capacity(); |
| |
| for_each_possible_cpu(i) |
| raw_spin_unlock(&cpu_rq(i)->lock); |
| local_irq_restore(flags); |
| } |
| |
| /* |
| * Return 'capacity' of a cpu in reference to "least" efficient cpu, such that |
| * least efficient cpu gets capacity of 1024 |
| */ |
| static unsigned long capacity_scale_cpu_efficiency(int cpu) |
| { |
| return (1024 * cpu_rq(cpu)->efficiency) / min_possible_efficiency; |
| } |
| |
| /* |
| * Return 'capacity' of a cpu in reference to cpu with lowest max_freq |
| * (min_max_freq), such that one with lowest max_freq gets capacity of 1024. |
| */ |
| static unsigned long capacity_scale_cpu_freq(int cpu) |
| { |
| return (1024 * cpu_rq(cpu)->max_freq) / min_max_freq; |
| } |
| |
| /* |
| * Return load_scale_factor of a cpu in reference to "most" efficient cpu, so |
| * that "most" efficient cpu gets a load_scale_factor of 1 |
| */ |
| static unsigned long load_scale_cpu_efficiency(int cpu) |
| { |
| return DIV_ROUND_UP(1024 * max_possible_efficiency, |
| cpu_rq(cpu)->efficiency); |
| } |
| |
| /* |
| * Return load_scale_factor of a cpu in reference to cpu with best max_freq |
| * (max_possible_freq), so that one with best max_freq gets a load_scale_factor |
| * of 1. |
| */ |
| static unsigned long load_scale_cpu_freq(int cpu) |
| { |
| return DIV_ROUND_UP(1024 * max_possible_freq, cpu_rq(cpu)->max_freq); |
| } |
| |
| static int compute_capacity(int cpu) |
| { |
| int capacity = 1024; |
| |
| capacity *= capacity_scale_cpu_efficiency(cpu); |
| capacity >>= 10; |
| |
| capacity *= capacity_scale_cpu_freq(cpu); |
| capacity >>= 10; |
| |
| return capacity; |
| } |
| |
| static int compute_load_scale_factor(int cpu) |
| { |
| int load_scale = 1024; |
| |
| /* |
| * load_scale_factor accounts for the fact that task load |
| * is in reference to "best" performing cpu. Task's load will need to be |
| * scaled (up) by a factor to determine suitability to be placed on a |
| * (little) cpu. |
| */ |
| load_scale *= load_scale_cpu_efficiency(cpu); |
| load_scale >>= 10; |
| |
| load_scale *= load_scale_cpu_freq(cpu); |
| load_scale >>= 10; |
| |
| return load_scale; |
| } |
| |
| static int cpufreq_notifier_policy(struct notifier_block *nb, |
| unsigned long val, void *data) |
| { |
| struct cpufreq_policy *policy = (struct cpufreq_policy *)data; |
| int i, update_max = 0; |
| u64 highest_mpc = 0, highest_mplsf = 0; |
| const struct cpumask *cpus = policy->related_cpus; |
| unsigned int orig_min_max_freq = min_max_freq; |
| unsigned int orig_max_possible_freq = max_possible_freq; |
| /* Initialized to policy->max in case policy->related_cpus is empty! */ |
| unsigned int orig_max_freq = policy->max; |
| |
| if (val != CPUFREQ_NOTIFY && val != CPUFREQ_REMOVE_POLICY && |
| val != CPUFREQ_CREATE_POLICY) |
| return 0; |
| |
| if (val == CPUFREQ_REMOVE_POLICY || val == CPUFREQ_CREATE_POLICY) { |
| update_min_max_capacity(); |
| return 0; |
| } |
| |
| for_each_cpu(i, policy->related_cpus) { |
| cpumask_copy(&cpu_rq(i)->freq_domain_cpumask, |
| policy->related_cpus); |
| orig_max_freq = cpu_rq(i)->max_freq; |
| cpu_rq(i)->min_freq = policy->min; |
| cpu_rq(i)->max_freq = policy->max; |
| cpu_rq(i)->cur_freq = policy->cur; |
| cpu_rq(i)->max_possible_freq = policy->cpuinfo.max_freq; |
| } |
| |
| max_possible_freq = max(max_possible_freq, policy->cpuinfo.max_freq); |
| if (min_max_freq == 1) |
| min_max_freq = UINT_MAX; |
| min_max_freq = min(min_max_freq, policy->cpuinfo.max_freq); |
| BUG_ON(!min_max_freq); |
| BUG_ON(!policy->max); |
| |
| /* Changes to policy other than max_freq don't require any updates */ |
| if (orig_max_freq == policy->max) |
| return 0; |
| |
| /* |
| * A changed min_max_freq or max_possible_freq (possible during bootup) |
| * needs to trigger re-computation of load_scale_factor and capacity for |
| * all possible cpus (even those offline). It also needs to trigger |
| * re-computation of nr_big_task count on all online cpus. |
| * |
| * A changed rq->max_freq otoh needs to trigger re-computation of |
| * load_scale_factor and capacity for just the cluster of cpus involved. |
| * Since small task definition depends on max_load_scale_factor, a |
| * changed load_scale_factor of one cluster could influence |
| * classification of tasks in another cluster. Hence a changed |
| * rq->max_freq will need to trigger re-computation of nr_big_task |
| * count on all online cpus. |
| * |
| * While it should be sufficient for nr_big_tasks to be |
| * re-computed for only online cpus, we have inadequate context |
| * information here (in policy notifier) with regard to hotplug-safety |
| * context in which notification is issued. As a result, we can't use |
| * get_online_cpus() here, as it can lead to deadlock. Until cpufreq is |
| * fixed up to issue notification always in hotplug-safe context, |
| * re-compute nr_big_task for all possible cpus. |
| */ |
| |
| if (orig_min_max_freq != min_max_freq || |
| orig_max_possible_freq != max_possible_freq) { |
| cpus = cpu_possible_mask; |
| update_max = 1; |
| } |
| |
| /* |
| * Changed load_scale_factor can trigger reclassification of tasks as |
| * big or small. Make this change "atomic" so that tasks are accounted |
| * properly due to changed load_scale_factor |
| */ |
| for_each_cpu(i, cpus) { |
| struct rq *rq = cpu_rq(i); |
| |
| rq->capacity = compute_capacity(i); |
| rq->load_scale_factor = compute_load_scale_factor(i); |
| |
| if (update_max) { |
| u64 mpc, mplsf; |
| |
| mpc = div_u64(((u64) rq->capacity) * |
| rq->max_possible_freq, rq->max_freq); |
| rq->max_possible_capacity = (int) mpc; |
| |
| mplsf = div_u64(((u64) rq->load_scale_factor) * |
| rq->max_possible_freq, rq->max_freq); |
| |
| if (mpc > highest_mpc) { |
| highest_mpc = mpc; |
| cpumask_clear(&mpc_mask); |
| cpumask_set_cpu(i, &mpc_mask); |
| } else if (mpc == highest_mpc) { |
| cpumask_set_cpu(i, &mpc_mask); |
| } |
| |
| if (mplsf > highest_mplsf) |
| highest_mplsf = mplsf; |
| } |
| } |
| |
| if (update_max) { |
| max_possible_capacity = highest_mpc; |
| max_load_scale_factor = highest_mplsf; |
| } |
| |
| __update_min_max_capacity(); |
| |
| return 0; |
| } |
| |
| static int cpufreq_notifier_trans(struct notifier_block *nb, |
| unsigned long val, void *data) |
| { |
| struct cpufreq_freqs *freq = (struct cpufreq_freqs *)data; |
| unsigned int cpu = freq->cpu, new_freq = freq->new; |
| unsigned long flags; |
| int i; |
| |
| if (val != CPUFREQ_POSTCHANGE) |
| return 0; |
| |
| BUG_ON(!new_freq); |
| |
| if (cpu_rq(cpu)->cur_freq == new_freq) |
| return 0; |
| |
| for_each_cpu(i, &cpu_rq(cpu)->freq_domain_cpumask) { |
| struct rq *rq = cpu_rq(i); |
| |
| raw_spin_lock_irqsave(&rq->lock, flags); |
| walt_update_task_ravg(rq->curr, rq, TASK_UPDATE, |
| walt_ktime_clock(), 0); |
| rq->cur_freq = new_freq; |
| raw_spin_unlock_irqrestore(&rq->lock, flags); |
| } |
| |
| return 0; |
| } |
| |
| static struct notifier_block notifier_policy_block = { |
| .notifier_call = cpufreq_notifier_policy |
| }; |
| |
| static struct notifier_block notifier_trans_block = { |
| .notifier_call = cpufreq_notifier_trans |
| }; |
| |
| static int register_sched_callback(void) |
| { |
| int ret; |
| |
| ret = cpufreq_register_notifier(¬ifier_policy_block, |
| CPUFREQ_POLICY_NOTIFIER); |
| |
| if (!ret) |
| ret = cpufreq_register_notifier(¬ifier_trans_block, |
| CPUFREQ_TRANSITION_NOTIFIER); |
| |
| return 0; |
| } |
| |
| /* |
| * cpufreq callbacks can be registered at core_initcall or later time. |
| * Any registration done prior to that is "forgotten" by cpufreq. See |
| * initialization of variable init_cpufreq_transition_notifier_list_called |
| * for further information. |
| */ |
| core_initcall(register_sched_callback); |
| |
| void walt_init_new_task_load(struct task_struct *p) |
| { |
| int i; |
| u32 init_load_windows = |
| div64_u64((u64)sysctl_sched_walt_init_task_load_pct * |
| (u64)walt_ravg_window, 100); |
| u32 init_load_pct = current->init_load_pct; |
| |
| p->init_load_pct = 0; |
| memset(&p->ravg, 0, sizeof(struct ravg)); |
| |
| if (init_load_pct) { |
| init_load_windows = div64_u64((u64)init_load_pct * |
| (u64)walt_ravg_window, 100); |
| } |
| |
| p->ravg.demand = init_load_windows; |
| for (i = 0; i < RAVG_HIST_SIZE_MAX; ++i) |
| p->ravg.sum_history[i] = init_load_windows; |
| } |