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Commit d9ff0d77 authored by Joonwoo Park's avatar Joonwoo Park Committed by Jeevan Shriram
Browse files

sched: simplify CPU frequency estimation and cycle counter API 



Most of CPUs increase cycle counter by one every cycle which makes
frequency = cycles / time_delta is correct.  Therefore it's reasonable
to get rid of current cpu_cycle_max_scale_factor and ask cycle counter
read callback function to return scaled counter value when it's needed
in such a case that cycle counter doesn't increase every cycle.

Thus multiply NSEC_PER_SEC / HZ_PER_KHZ to CPU cycle counter delta
as we calculate frequency in khz and remove cpu_cycle_max_scale_factor.
This allows us to simplify frequency estimation and cycle counter API.

Change-Id: Ie7a628d4bc77c9b6c769f6099ce8d75740262a14
Signed-off-by: default avatarJoonwoo Park <joonwoop@codeaurora.org>
parent 167eebb0

include/linux/sched.h

+0 −1
Original line number Original line Diff line number Diff line
@@ -3370,7 +3370,6 @@ static inline unsigned long rlimit_max(unsigned int limit) 




struct cpu_cycle_counter_cb {

struct cpu_cycle_counter_cb {

	u64 (*get_cpu_cycle_counter)(int cpu);

	u64 (*get_cpu_cycle_counter)(int cpu);

	u32 (*get_cpu_cycles_max_per_us)(int cpu);

};

};

int register_cpu_cycle_counter_cb(struct cpu_cycle_counter_cb *cb);

int register_cpu_cycle_counter_cb(struct cpu_cycle_counter_cb *cb);

kernel/sched/core.c

+3 −29
Original line number Original line Diff line number Diff line
@@ -1403,7 +1403,6 @@ static struct sched_cluster init_cluster = { 
	.max_mitigated_freq	=	UINT_MAX,

	.max_mitigated_freq	=	UINT_MAX,

	.min_freq		=	1,

	.min_freq		=	1,

	.max_possible_freq	=	1,

	.max_possible_freq	=	1,

	.cpu_cycle_max_scale_factor	= 1,

	.dstate			=	0,

	.dstate			=	0,

	.dstate_wakeup_energy	=	0,

	.dstate_wakeup_energy	=	0,

	.dstate_wakeup_latency	=	0,

	.dstate_wakeup_latency	=	0,
@@ -1553,7 +1552,6 @@ static struct sched_cluster *alloc_new_cluster(const struct cpumask *cpus) 
	cluster->max_mitigated_freq	=	UINT_MAX;

	cluster->max_mitigated_freq	=	UINT_MAX;

	cluster->min_freq		=	1;

	cluster->min_freq		=	1;

	cluster->max_possible_freq	=	1;

	cluster->max_possible_freq	=	1;

	cluster->cpu_cycle_max_scale_factor =	1;

	cluster->dstate			=	0;

	cluster->dstate			=	0;

	cluster->dstate_wakeup_energy	=	0;

	cluster->dstate_wakeup_energy	=	0;

	cluster->dstate_wakeup_latency	=	0;

	cluster->dstate_wakeup_latency	=	0;
@@ -1620,38 +1618,15 @@ static void init_clusters(void) 
	INIT_LIST_HEAD(&cluster_head);

	INIT_LIST_HEAD(&cluster_head);

}

}





static inline void

__update_cpu_cycle_max_possible_freq(struct sched_cluster *cluster)

{

	int cpu = cluster_first_cpu(cluster);



	cluster->cpu_cycle_max_scale_factor =

	    div64_u64(cluster->max_possible_freq * NSEC_PER_USEC,

		      cpu_cycle_counter_cb.get_cpu_cycles_max_per_us(cpu));

}



static inline void

update_cpu_cycle_max_possible_freq(struct sched_cluster *cluster)

{

	if (!use_cycle_counter)

		return;



	__update_cpu_cycle_max_possible_freq(cluster);

}



int register_cpu_cycle_counter_cb(struct cpu_cycle_counter_cb *cb)

int register_cpu_cycle_counter_cb(struct cpu_cycle_counter_cb *cb)

{

{

	struct sched_cluster *cluster = NULL;



	mutex_lock(&cluster_lock);

	mutex_lock(&cluster_lock);

	if (!cb->get_cpu_cycle_counter || !cb->get_cpu_cycles_max_per_us) {

	if (!cb->get_cpu_cycle_counter) {

		mutex_unlock(&cluster_lock);

		mutex_unlock(&cluster_lock);

		return -EINVAL;

		return -EINVAL;

	}

	}





	cpu_cycle_counter_cb = *cb;

	cpu_cycle_counter_cb = *cb;

	for_each_sched_cluster(cluster)

		__update_cpu_cycle_max_possible_freq(cluster);

	use_cycle_counter = true;

	use_cycle_counter = true;

	mutex_unlock(&cluster_lock);

	mutex_unlock(&cluster_lock);
@@ -1931,8 +1906,7 @@ static inline u64 scale_exec_time(u64 delta, struct rq *rq, 
	int cpu = cpu_of(rq);

	int cpu = cpu_of(rq);

	int sf;

	int sf;





	delta = DIV64_U64_ROUNDUP(delta * cc->cycles *

	delta = DIV64_U64_ROUNDUP(delta * cc->cycles,

				  cpu_cycle_max_scale_factor(cpu),

				  max_possible_freq * cc->time);

				  max_possible_freq * cc->time);

	sf = DIV_ROUND_UP(cpu_efficiency(cpu) * 1024, max_possible_efficiency);

	sf = DIV_ROUND_UP(cpu_efficiency(cpu) * 1024, max_possible_efficiency);
@@ -2613,6 +2587,7 @@ get_task_cpu_cycles(struct task_struct *p, struct rq *rq, int event, 
		cc.cycles = cur_cycles + (U64_MAX - p->cpu_cycles);

		cc.cycles = cur_cycles + (U64_MAX - p->cpu_cycles);

	else

	else

		cc.cycles = cur_cycles - p->cpu_cycles;

		cc.cycles = cur_cycles - p->cpu_cycles;

	cc.cycles = cc.cycles * NSEC_PER_MSEC;

	cc.time = wallclock - p->ravg.mark_start;

	cc.time = wallclock - p->ravg.mark_start;

	BUG_ON((s64)cc.time < 0);

	BUG_ON((s64)cc.time < 0);
@@ -3688,7 +3663,6 @@ static int cpufreq_notifier_policy(struct notifier_block *nb, 




			sort_clusters();

			sort_clusters();

			update_all_clusters_stats();

			update_all_clusters_stats();

			update_cpu_cycle_max_possible_freq(cluster);

			mutex_unlock(&cluster_lock);

			mutex_unlock(&cluster_lock);

			continue;

			continue;

		}

		}

kernel/sched/sched.h

+1 −11
Original line number Original line Diff line number Diff line
@@ -389,11 +389,6 @@ struct sched_cluster { 
	 */

	 */

	unsigned int cur_freq, max_freq, max_mitigated_freq, min_freq;

	unsigned int cur_freq, max_freq, max_mitigated_freq, min_freq;

	unsigned int max_possible_freq;

	unsigned int max_possible_freq;

	/*

	 * cpu_cycle_max_scale_factor represents number of cycles per NSEC at

	 * CPU's fmax.

	 */

	u32 cpu_cycle_max_scale_factor;

	bool freq_init_done;

	bool freq_init_done;

	int dstate, dstate_wakeup_latency, dstate_wakeup_energy;

	int dstate, dstate_wakeup_latency, dstate_wakeup_energy;

	unsigned int static_cluster_pwr_cost;

	unsigned int static_cluster_pwr_cost;
@@ -1137,14 +1132,9 @@ static inline int cpu_max_power_cost(int cpu) 
	return cpu_rq(cpu)->cluster->max_power_cost;

	return cpu_rq(cpu)->cluster->max_power_cost;

}

}





static inline int cpu_cycle_max_scale_factor(int cpu)

{

	return cpu_rq(cpu)->cluster->cpu_cycle_max_scale_factor;

}



static inline u32 cpu_cycles_to_freq(int cpu, u64 cycles, u32 period)

static inline u32 cpu_cycles_to_freq(int cpu, u64 cycles, u32 period)

{

{

	return div64_u64(cycles * cpu_cycle_max_scale_factor(cpu), period);

	return div64_u64(cycles, period);

}

}





static inline bool hmp_capable(void)

static inline bool hmp_capable(void)