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Commit a3c1ecd8 authored by Srivatsa Vaddagiri's avatar Srivatsa Vaddagiri Committed by Steve Muckle
Browse files

sched: window-stats: Account idle time as busy time 



Provide a knob to consider idle time as busy time, when cpu becomes
idle as a result of io_schedule() call. This will let governor
parameter 'io_is_busy' to be appropriately honored.

Change-Id: Id9fb4fe448e8e4909696aa8a3be5a165ad7529d3
Signed-off-by: default avatarSrivatsa Vaddagiri <vatsa@codeaurora.org>
parent c55cc8b6

include/linux/sched.h

+1 −1
Original line number Diff line number Diff line
@@ -1719,8 +1719,8 @@ extern void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut, 
extern int task_free_register(struct notifier_block *n);

extern int task_free_unregister(struct notifier_block *n);

extern int sched_set_window(u64 window_start, unsigned int window_size);

static inline void sched_set_io_is_busy(int val) {};

extern unsigned long sched_get_busy(int cpu);

extern void sched_set_io_is_busy(int val);



/*

 * Per process flags

kernel/sched/core.c

+39 −8
Original line number Diff line number Diff line
@@ -1136,6 +1136,7 @@ unsigned int min_possible_efficiency = 1024; 
__read_mostly int sysctl_sched_freq_inc_notify_slack_pct;

__read_mostly int sysctl_sched_freq_dec_notify_slack_pct = 25;

static __read_mostly unsigned int sched_account_wait_time = 1;

static __read_mostly unsigned int sched_io_is_busy;



/*

 * Maximum possible frequency across all cpus. Task demand and cpu
@@ -1301,6 +1302,14 @@ static int __init set_sched_ravg_window(char *str) 


early_param("sched_ravg_window", set_sched_ravg_window);



static inline int cpu_is_waiting_on_io(struct rq *rq)

{

	if (!sched_io_is_busy)

		return 0;



	return atomic_read(&rq->nr_iowait);

}



static inline void

move_window_start(struct rq *rq, u64 wallclock, int update_sum,

						 struct task_struct *p)
@@ -1316,7 +1325,7 @@ move_window_start(struct rq *rq, u64 wallclock, int update_sum, 
	nr_windows = div64_u64(delta, sched_ravg_window);

	rq->window_start += (u64)nr_windows * (u64)sched_ravg_window;



	if (is_idle_task(rq->curr)) {

	if (is_idle_task(rq->curr) && !cpu_is_waiting_on_io(rq)) {

		if (nr_windows == 1)

			rq->prev_runnable_sum = rq->curr_runnable_sum;

		else
@@ -1372,6 +1381,7 @@ static void update_task_ravg(struct task_struct *p, struct rq *rq, 
	int update_sum, new_window;

	u64 mark_start = p->ravg.mark_start;

	u64 window_start;

	s64 delta = 0;



	if (sched_use_pelt || !rq->window_start)

		return;
@@ -1385,15 +1395,30 @@ static void update_task_ravg(struct task_struct *p, struct rq *rq, 
	move_window_start(rq, wallclock, update_sum, p);

	window_start = rq->window_start;



	/*

	 * Don't bother accounting for idle task, also we would not want

	 * to attribute its time to the aggregate RQ busy time

	 */

	if (is_idle_task(p))

		return;

	if (is_idle_task(p)) {

		if (!(event == PUT_PREV_TASK && cpu_is_waiting_on_io(rq)))

			goto done;



		if (window_start > mark_start) {

			delta = window_start - mark_start;

			if (delta > window_size) {

				rq->curr_runnable_sum = 0;

				delta = window_size;

			}

			delta = scale_exec_time(delta, rq);

			rq->curr_runnable_sum += delta;

			rq->prev_runnable_sum = rq->curr_runnable_sum;

			rq->curr_runnable_sum = 0;

			mark_start = window_start;

		}

		delta = wallclock - mark_start;

		delta = scale_exec_time(delta, rq);

		rq->curr_runnable_sum += delta;



		goto done;

	}



	do {

		s64 delta = 0;

		int nr_full_windows = 0;

		u64 now = wallclock;

		u32 sum = 0;
@@ -1473,6 +1498,7 @@ static void update_task_ravg(struct task_struct *p, struct rq *rq, 
		}

	}



done:

	trace_sched_update_task_ravg(p, rq, event, wallclock);



	p->ravg.mark_start = wallclock;
@@ -1630,6 +1656,11 @@ void reset_all_window_stats(u64 window_start, unsigned int window_size, 
	}

}



void sched_set_io_is_busy(int val)

{

	sched_io_is_busy = val;

}



int sched_set_window(u64 window_start, unsigned int window_size)

{

	u64 ws, now;