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Commit df91ad27 authored by Olav Haugan's avatar Olav Haugan Committed by Steve Muckle
Browse files

sched: Make RAVG_HIST_SIZE tunable 



Make RAVG_HIST_SIZE available from /proc/sys/kernel/sched_ravg_hist_size
to allow tuning of the size of the history that is used in computation
of task demand.

CRs-fixed: 706138
Change-Id: Id54c1e4b6e974a62d787070a0af1b4e8ce3b4be6
Signed-off-by: default avatarOlav Haugan <ohaugan@codeaurora.org>
parent 7b76c244

include/linux/sched.h

+5 −4
Original line number Diff line number Diff line
@@ -1045,7 +1045,7 @@ struct sched_statistics { 
};

#endif



#define RAVG_HIST_SIZE  5

#define RAVG_HIST_SIZE_MAX  5



/* ravg represents frequency scaled cpu-demand of tasks */

struct ravg {
@@ -1061,8 +1061,9 @@ struct ravg { 
	 * RAVG_HIST_SIZE windows. Windows where task was entirely sleeping are

	 * ignored.

	 *

	 * 'demand' represents maximum sum seen over previous RAVG_HIST_SIZE

	 * windows. 'demand' could drive frequency demand for tasks.

	 * 'demand' represents maximum sum seen over previous

	 * sysctl_sched_ravg_hist_size windows. 'demand' could drive frequency

	 * demand for tasks.

	 *

	 * 'prev_window' is the history in the most recent window. This value

	 * may be zero if there was no task activity in that window - that is
@@ -1074,7 +1075,7 @@ struct ravg { 
	 */

	u64 mark_start;

	u32 sum, demand, prev_window, partial_demand, flags;

	u32 sum_history[RAVG_HIST_SIZE];

	u32 sum_history[RAVG_HIST_SIZE_MAX];

};



struct sched_entity {

include/linux/sched/sysctl.h

+4 −0
Original line number Diff line number Diff line
@@ -39,6 +39,7 @@ extern unsigned int sysctl_sched_wake_to_idle; 
extern unsigned int sysctl_sched_wakeup_load_threshold;

extern unsigned int sysctl_sched_window_stats_policy;

extern unsigned int sysctl_sched_account_wait_time;

extern unsigned int sysctl_sched_ravg_hist_size;



#if defined(CONFIG_SCHED_FREQ_INPUT) || defined(CONFIG_SCHED_HMP)

extern unsigned int sysctl_sched_init_task_load_pct;
@@ -109,6 +110,9 @@ extern int sched_acct_wait_time_update_handler(struct ctl_table *table, 
extern int sched_window_stats_policy_update_handler(struct ctl_table *table,

		 int write, void __user *buffer, size_t *lenp, loff_t *ppos);



extern int sched_ravg_hist_size_update_handler(struct ctl_table *table,

		 int write, void __user *buffer, size_t *lenp, loff_t *ppos);



#ifdef CONFIG_SCHED_DEBUG

static inline unsigned int get_sysctl_timer_migration(void)

{

include/trace/events/sched.h

+2 −2
Original line number Diff line number Diff line
@@ -287,7 +287,7 @@ TRACE_EVENT(sched_update_history, 
		__field(enum task_event,	evt		)

		__field(unsigned int,	partial_demand		)

		__field(unsigned int,	demand			)

		__array(         u32,	hist,   RAVG_HIST_SIZE	)

		__array(	 u32,	hist, RAVG_HIST_SIZE_MAX)

		__field(unsigned int,	nr_big_tasks		)

		__field(unsigned int,	nr_small_tasks		)

		__field(	 int,	cpu			)
@@ -304,7 +304,7 @@ TRACE_EVENT(sched_update_history, 
		__entry->partial_demand = p->ravg.partial_demand;

		__entry->demand         = p->ravg.demand;

		memcpy(__entry->hist, p->ravg.sum_history,

					RAVG_HIST_SIZE*sizeof(u32));

					RAVG_HIST_SIZE_MAX * sizeof(u32));

#ifdef CONFIG_SCHED_HMP

		__entry->nr_big_tasks   = rq->nr_big_tasks;

		__entry->nr_small_tasks = rq->nr_small_tasks;

kernel/sched/core.c

+32 −13
Original line number Diff line number Diff line
@@ -1103,6 +1103,17 @@ static inline void clear_hmp_request(int cpu) { } 


#if defined(CONFIG_SCHED_FREQ_INPUT) || defined(CONFIG_SCHED_HMP)



__read_mostly unsigned int sysctl_sched_ravg_hist_size = 5;



/*

 * copy of sysctl_sched_ravg_hist_size. Required for atomically

 * changing the ravg history size (see sched_ravg_hist_size_update_handler()

 * for details).

 *

 * Initialize both to same value!!

 */

static __read_mostly unsigned int sched_ravg_hist_size = 5;



/* Window size (in ns) */

__read_mostly unsigned int sched_ravg_window = 10000000;
@@ -1225,7 +1236,7 @@ update_history(struct rq *rq, struct task_struct *p, u32 runtime, int samples, 
		return;



	if (!new_window) {

		for (ridx = 0; ridx < RAVG_HIST_SIZE - 1; ++ridx) {

		for (ridx = 0; ridx < sched_ravg_hist_size - 1; ++ridx) {

			sum += hist[ridx];

			if (hist[ridx] > max)

				max = hist[ridx];
@@ -1237,21 +1248,25 @@ update_history(struct rq *rq, struct task_struct *p, u32 runtime, int samples, 
	}



	/* Push new 'runtime' value onto stack */

	widx = RAVG_HIST_SIZE - 1;

	widx = RAVG_HIST_SIZE_MAX - 1;

	ridx = widx - samples;

	for (; ridx >= 0; --widx, --ridx) {

		hist[widx] = hist[ridx];

		if (widx < sched_ravg_hist_size) {

			sum += hist[widx];

			if (hist[widx] > max)

				max = hist[widx];

		}

	}



	for (widx = 0; widx < samples && widx < RAVG_HIST_SIZE; widx++) {

	for (widx = 0; widx < samples && widx < RAVG_HIST_SIZE_MAX; widx++) {

		hist[widx] = runtime;

		if (widx < sched_ravg_hist_size) {

			sum += hist[widx];

			if (hist[widx] > max)

				max = hist[widx];

		}

	}



	p->ravg.sum = 0;

	if (p->on_rq) {
@@ -1262,7 +1277,7 @@ update_history(struct rq *rq, struct task_struct *p, u32 runtime, int samples, 
	}



compute_demand:

	avg = div64_u64(sum, RAVG_HIST_SIZE);

	avg = div64_u64(sum, sched_ravg_hist_size);



	if (sched_window_stats_policy == WINDOW_STATS_USE_RECENT)

		demand = runtime;
@@ -1630,7 +1645,8 @@ unsigned long sched_get_busy(int cpu) 


/* Called with IRQs disabled */

void reset_all_window_stats(u64 window_start, unsigned int window_size,

				 int policy, int acct_wait_time)

				 int policy, int acct_wait_time,

				 unsigned int ravg_hist_size)

{

	int cpu;

	u64 wallclock;
@@ -1657,7 +1673,7 @@ void reset_all_window_stats(u64 window_start, unsigned int window_size, 
		p->ravg.partial_demand = 0;

		p->ravg.prev_window = 0;

		p->ravg.flags = 0;

		for (i = 0; i < RAVG_HIST_SIZE; ++i)

		for (i = 0; i < RAVG_HIST_SIZE_MAX; ++i)

			p->ravg.sum_history[i] = 0;

		p->ravg.mark_start = wallclock;

	}  while_each_thread(g, p);
@@ -1679,6 +1695,9 @@ void reset_all_window_stats(u64 window_start, unsigned int window_size, 
	if (acct_wait_time >= 0)

		sched_account_wait_time = acct_wait_time;



	if (ravg_hist_size > 0)

		sched_ravg_hist_size = ravg_hist_size;



	for_each_online_cpu(cpu) {

		struct rq *rq = cpu_rq(cpu);

		raw_spin_unlock(&rq->lock);
@@ -1716,7 +1735,7 @@ int sched_set_window(u64 window_start, unsigned int window_size) 


	BUG_ON(sched_clock() < ws);



	reset_all_window_stats(ws, window_size, -1, -1);

	reset_all_window_stats(ws, window_size, -1, -1, 0);



	local_irq_restore(flags);

kernel/sched/fair.c

+41 −3
Original line number Diff line number Diff line
@@ -1910,7 +1910,45 @@ int sched_acct_wait_time_update_handler(struct ctl_table *table, int write, 


	local_irq_save(flags);



	reset_all_window_stats(0, 0, -1, sysctl_sched_account_wait_time);

	reset_all_window_stats(0, 0, -1, sysctl_sched_account_wait_time, 0);



	local_irq_restore(flags);



done:

	mutex_unlock(&policy_mutex);



	return ret;

}



int sched_ravg_hist_size_update_handler(struct ctl_table *table, int write,

		void __user *buffer, size_t *lenp,

		loff_t *ppos)

{

	int ret;

	unsigned int *data = (unsigned int *)table->data;

	unsigned int old_val;

	unsigned long flags;



	if (!sched_enable_hmp)

		return -EINVAL;



	mutex_lock(&policy_mutex);



	old_val = *data;



	ret = proc_dointvec(table, write, buffer, lenp, ppos);

	if (ret || !write || (write && (old_val == *data)))

		goto done;



	if (*data > RAVG_HIST_SIZE_MAX || *data < 1) {

		*data = old_val;

		ret = -EINVAL;

		goto done;

	}



	local_irq_save(flags);



	reset_all_window_stats(0, 0, -1, -1, sysctl_sched_ravg_hist_size);



	local_irq_restore(flags);
@@ -1942,7 +1980,7 @@ int sched_window_stats_policy_update_handler(struct ctl_table *table, int write, 


	local_irq_save(flags);



	reset_all_window_stats(0, 0, sysctl_sched_window_stats_policy, -1);

	reset_all_window_stats(0, 0, sysctl_sched_window_stats_policy, -1, 0);



	local_irq_restore(flags);
@@ -2240,7 +2278,7 @@ void init_new_task_load(struct task_struct *p) 
	p->ravg.sum		= 0;

	p->ravg.flags = 0;



	for (i = 0; i < RAVG_HIST_SIZE; ++i)

	for (i = 0; i < RAVG_HIST_SIZE_MAX; ++i)

		p->ravg.sum_history[i] = sched_init_task_load_windows;

	p->se.avg.runnable_avg_period =

		sysctl_sched_init_task_load_pct ? LOAD_AVG_MAX : 0;