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Commit b02fc008 authored by Joonwoo Park's avatar Joonwoo Park
Browse files

sched: introduce sched_{up,down}migrate knobs 



Introduce knobs sched_upmigrate and sched_downmigrate to
control thresholds to up and down migrate tasks between clusters at a
runtime for ease of power and performance tuning.

Change-Id: I17a464388b404b61d9a9dbe1beee4883c4db8e3f
Signed-off-by: default avatarJoonwoo Park <joonwoop@codeaurora.org>
parent 6f18847e

include/linux/sched/sysctl.h

+6 −0
Original line number Diff line number Diff line
@@ -22,6 +22,8 @@ extern unsigned int sysctl_sched_is_big_little; 
extern unsigned int sysctl_sched_sync_hint_enable;

extern unsigned int sysctl_sched_initial_task_util;

extern unsigned int sysctl_sched_cstate_aware;

extern unsigned int sysctl_sched_capacity_margin;

extern unsigned int sysctl_sched_capacity_margin_down;

#ifdef CONFIG_SCHED_WALT

extern unsigned int sysctl_sched_use_walt_cpu_util;

extern unsigned int sysctl_sched_use_walt_task_util;
@@ -156,6 +158,10 @@ extern int sched_rt_handler(struct ctl_table *table, int write, 
		void __user *buffer, size_t *lenp,

		loff_t *ppos);



extern int sched_updown_migrate_handler(struct ctl_table *table,

					int write, void __user *buffer,

					size_t *lenp, loff_t *ppos);



extern int sysctl_numa_balancing(struct ctl_table *table, int write,

				 void __user *buffer, size_t *lenp,

				 loff_t *ppos);

include/linux/sysctl.h

+3 −0
Original line number Diff line number Diff line
@@ -59,6 +59,9 @@ extern int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int, 
				      void __user *, size_t *, loff_t *);

extern int proc_do_large_bitmap(struct ctl_table *, int,

				void __user *, size_t *, loff_t *);

extern int proc_douintvec_capacity(struct ctl_table *table, int write,

				   void __user *buffer, size_t *lenp,

				   loff_t *ppos);



/*

 * Register a set of sysctl names by calling register_sysctl_table

kernel/sched/core.c

+26 −0
Original line number Diff line number Diff line
@@ -9137,6 +9137,32 @@ int sched_rr_handler(struct ctl_table *table, int write, 
	return ret;

}



#ifdef CONFIG_PROC_SYSCTL

int sched_updown_migrate_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;

	static DEFINE_MUTEX(mutex);



	mutex_lock(&mutex);

	old_val = *data;



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



	if (!ret && write &&

	    sysctl_sched_capacity_margin > sysctl_sched_capacity_margin_down) {

		ret = -EINVAL;

		*data = old_val;

	}

	mutex_unlock(&mutex);



	return ret;

}

#endif



#ifdef CONFIG_CGROUP_SCHED



inline struct task_group *css_tg(struct cgroup_subsys_state *css)

kernel/sched/fair.c

+10 −6
Original line number Diff line number Diff line
@@ -221,8 +221,8 @@ unsigned int sysctl_sched_cfs_bandwidth_slice = 5000UL; 
 * The margin used when comparing utilization with CPU capacity:

 * util * 1024 < capacity * margin

 */

unsigned int capacity_margin = 1078; /* ~5% margin */

unsigned int capacity_margin_down = 1205; /* ~15% margin */

unsigned int sysctl_sched_capacity_margin = 1078; /* ~5% margin */

unsigned int sysctl_sched_capacity_margin_down = 1205; /* ~15% margin */



static inline void update_load_add(struct load_weight *lw, unsigned long inc)

{
@@ -5931,9 +5931,9 @@ static inline bool __task_fits(struct task_struct *p, int cpu, int util) 
	util += boosted_task_util(p);



	if (capacity_orig_of(task_cpu(p)) > capacity_orig_of(cpu))

		margin = capacity_margin_down;

		margin = sysctl_sched_capacity_margin_down;

	else

		margin = capacity_margin;

		margin = sysctl_sched_capacity_margin;



	return (capacity_orig_of(cpu) * 1024) > (util * margin);

}
@@ -5961,7 +5961,7 @@ static inline bool task_fits_spare(struct task_struct *p, int cpu) 
static bool __cpu_overutilized(int cpu, int delta)

{

	return (capacity_orig_of(cpu) * 1024) <

	       ((cpu_util(cpu) + delta) * capacity_margin);

	       ((cpu_util(cpu) + delta) * sysctl_sched_capacity_margin);

}



bool cpu_overutilized(int cpu)
@@ -6098,10 +6098,14 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p, 
	struct sched_group *fit_group = NULL, *spare_group = NULL;

	unsigned long min_load = ULONG_MAX, this_load = 0;

	unsigned long fit_capacity = ULONG_MAX;

	unsigned long max_spare_capacity = capacity_margin - SCHED_CAPACITY_SCALE;

	unsigned long max_spare_capacity;



	int load_idx = sd->forkexec_idx;

	int imbalance = 100 + (sd->imbalance_pct-100)/2;



	max_spare_capacity = sysctl_sched_capacity_margin -

			     SCHED_CAPACITY_SCALE;



	if (sd_flag & SD_BALANCE_WAKE)

		load_idx = sd->wake_idx;

kernel/sysctl.c

+52 −0
Original line number Diff line number Diff line
@@ -586,6 +586,20 @@ static struct ctl_table kern_table[] = { 
		.extra1		= &min_wakeup_granularity_ns,

		.extra2		= &max_wakeup_granularity_ns,

	},

	{

		.procname	= "sched_upmigrate",

		.data		= &sysctl_sched_capacity_margin,

		.maxlen		= sizeof(unsigned int),

		.mode		= 0644,

		.proc_handler	= sched_updown_migrate_handler,

	},

	{

		.procname	= "sched_downmigrate",

		.data		= &sysctl_sched_capacity_margin_down,

		.maxlen		= sizeof(unsigned int),

		.mode		= 0644,

		.proc_handler	= sched_updown_migrate_handler,

	},

#ifdef CONFIG_SMP

	{

		.procname	= "sched_tunable_scaling",
@@ -3181,6 +3195,39 @@ int proc_do_large_bitmap(struct ctl_table *table, int write, 
	}

}



static int do_proc_douintvec_capacity_conv(bool *negp, unsigned long *lvalp,

					   int *valp, int write, void *data)

{

	if (write) {

		if (*negp)

			return -EINVAL;

		*valp = SCHED_FIXEDPOINT_SCALE * 100 / *lvalp;

	} else {

		*negp = false;

		*lvalp = SCHED_FIXEDPOINT_SCALE * 100 / *valp;

	}



	return 0;

}



/**

 * proc_douintvec_capacity - read a vector of integers in percentage and convert

 *			    into sched capacity

 * @table: the sysctl table

 * @write: %TRUE if this is a write to the sysctl file

 * @buffer: the user buffer

 * @lenp: the size of the user buffer

 * @ppos: file position

 *

 * Returns 0 on success.

 */

int proc_douintvec_capacity(struct ctl_table *table, int write,

			    void __user *buffer, size_t *lenp, loff_t *ppos)

{

	return do_proc_dointvec(table, write, buffer, lenp, ppos,

				do_proc_douintvec_capacity_conv, NULL);

}



#else /* CONFIG_PROC_SYSCTL */



int proc_dostring(struct ctl_table *table, int write,
@@ -3238,6 +3285,11 @@ int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int write, 
    return -ENOSYS;

}



int proc_douintvec_capacity(struct ctl_table *table, int write,

			    void __user *buffer, size_t *lenp, loff_t *ppos)

{

	return -ENOSYS;

}



#endif /* CONFIG_PROC_SYSCTL */