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Commit 345ef1c3 authored by Junjie Wu's avatar Junjie Wu
Browse files

cpufreq: interactive: Add max_freq_hysteresis feature 



Previously known as sampling down factor, max_freq_hysteresis
extends the period that interactive governor will stay at policy->max.
This feature is to accomodate short idle periods in an otherwise very
intensive workload.

When the feature is enabled, it ensures that once a CPU goes to max
frequency, it doesn't reduce the frequency for max_freq_hysteresis
microseconds from the time it first goes to idle.

Change-Id: Ia54985cb554f63f8c22d0b554a0a0f2ed2be038f
Signed-off-by: default avatarJunjie Wu <junjiew@codeaurora.org>
parent 3511ae2a

drivers/cpufreq/cpufreq_interactive.c

+60 −1
Original line number Diff line number Diff line
@@ -53,6 +53,7 @@ struct cpufreq_interactive_cpuinfo { 
	unsigned int max_freq;

	u64 floor_validate_time;

	u64 hispeed_validate_time;

	u64 max_freq_idle_start_time;

	struct rw_semaphore enable_sem;

	int governor_enabled;

	struct cpufreq_interactive_tunables *cached_tunables;
@@ -125,6 +126,12 @@ struct cpufreq_interactive_tunables { 
	/* scheduler input related flags */

	bool use_sched_load;

	bool use_migration_notif;



	/*

	 * Stay at max freq for at least max_freq_hysteresis before dropping

	 * frequency.

	 */

	unsigned int max_freq_hysteresis;

};



/* For cases where we have single governor instance for system */
@@ -476,6 +483,16 @@ static void cpufreq_interactive_timer(unsigned long data) 


	new_freq = pcpu->freq_table[index].frequency;



	if (pcpu->target_freq >= pcpu->policy->max

	    && new_freq < pcpu->target_freq

	    && now - pcpu->max_freq_idle_start_time <

	    tunables->max_freq_hysteresis) {

		trace_cpufreq_interactive_notyet(data, cpu_load,

			pcpu->target_freq, pcpu->policy->cur, new_freq);

		spin_unlock_irqrestore(&pcpu->target_freq_lock, flags);

		goto rearm;

	}



	/*

	 * Do not scale below floor_freq unless we have been at or above the

	 * floor frequency for the minimum sample time since last validated.
@@ -544,6 +561,9 @@ static void cpufreq_interactive_idle_start(void) 
	struct cpufreq_interactive_cpuinfo *pcpu =

		&per_cpu(cpuinfo, smp_processor_id());

	int pending;

	struct cpufreq_interactive_tunables *tunables;

	unsigned long flags;

	u64 now;



	if (!down_read_trylock(&pcpu->enable_sem))

		return;
@@ -566,9 +586,23 @@ static void cpufreq_interactive_idle_start(void) 
		if (!pending) {

			pcpu->last_evaluated_jiffy = get_jiffies_64();

			cpufreq_interactive_timer_resched(smp_processor_id());



			/*

			 * If timer is cancelled because CPU is running at

			 * policy->max, record the time CPU first goes to

			 * idle.

			 */

			now = ktime_to_us(ktime_get());

			tunables = pcpu->policy->governor_data;

			if (tunables->max_freq_hysteresis) {

				spin_lock_irqsave(&pcpu->target_freq_lock,

						  flags);

				pcpu->max_freq_idle_start_time = now;

				spin_unlock_irqrestore(&pcpu->target_freq_lock,

						       flags);

			}

		}

	}



	up_read(&pcpu->enable_sem);

}
@@ -912,6 +946,27 @@ static ssize_t store_hispeed_freq(struct cpufreq_interactive_tunables *tunables, 
	return count;

}



#define show_store_one(file_name)					\

static ssize_t show_##file_name(					\

	struct cpufreq_interactive_tunables *tunables, char *buf)	\

{									\

	return snprintf(buf, PAGE_SIZE, "%u\n", tunables->file_name);	\

}									\

static ssize_t store_##file_name(					\

		struct cpufreq_interactive_tunables *tunables,		\

		const char *buf, size_t count)				\

{									\

	int ret;							\

	long unsigned int val;						\

									\

	ret = kstrtoul(buf, 0, &val);				\

	if (ret < 0)							\

		return ret;						\

	tunables->file_name = val;					\

	return count;							\

}

show_store_one(max_freq_hysteresis);



static ssize_t show_go_hispeed_load(struct cpufreq_interactive_tunables

		*tunables, char *buf)

{
@@ -1290,6 +1345,7 @@ show_store_gov_pol_sys(boostpulse_duration); 
show_store_gov_pol_sys(io_is_busy);

show_store_gov_pol_sys(use_sched_load);

show_store_gov_pol_sys(use_migration_notif);

show_store_gov_pol_sys(max_freq_hysteresis);



#define gov_sys_attr_rw(_name)						\

static struct global_attr _name##_gov_sys =				\
@@ -1315,6 +1371,7 @@ gov_sys_pol_attr_rw(boostpulse_duration); 
gov_sys_pol_attr_rw(io_is_busy);

gov_sys_pol_attr_rw(use_sched_load);

gov_sys_pol_attr_rw(use_migration_notif);

gov_sys_pol_attr_rw(max_freq_hysteresis);



static struct global_attr boostpulse_gov_sys =

	__ATTR(boostpulse, 0200, NULL, store_boostpulse_gov_sys);
@@ -1337,6 +1394,7 @@ static struct attribute *interactive_attributes_gov_sys[] = { 
	&io_is_busy_gov_sys.attr,

	&use_sched_load_gov_sys.attr,

	&use_migration_notif_gov_sys.attr,

	&max_freq_hysteresis_gov_sys.attr,

	NULL,

};
@@ -1360,6 +1418,7 @@ static struct attribute *interactive_attributes_gov_pol[] = { 
	&io_is_busy_gov_pol.attr,

	&use_sched_load_gov_pol.attr,

	&use_migration_notif_gov_pol.attr,

	&max_freq_hysteresis_gov_pol.attr,

	NULL,

};