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Commit 1302a3d8 authored by Connor O'Brien's avatar Connor O'Brien
Browse files

ANDROID: cpufreq: track per-task time in state 



Add time in state data to task structs, and create
/proc/<pid>/time_in_state files to show how long each individual task
has run at each frequency.
Create a CONFIG_CPU_FREQ_TIMES option to enable/disable this tracking.

Signed-off-by: default avatarConnor O'Brien <connoro@google.com>
Bug: 72339335
Test: Read /proc/<pid>/time_in_state
Change-Id: Ia6456754f4cb1e83b2bc35efa8fbe9f8696febc8
parent a2a9032a

drivers/cpufreq/Kconfig

+7 −0
Original line number Diff line number Diff line
@@ -37,6 +37,13 @@ config CPU_FREQ_STAT 


	  If in doubt, say N.



config CPU_FREQ_TIMES

       bool "CPU frequency time-in-state statistics"

       help

         Export CPU time-in-state information through procfs.



         If in doubt, say N.



choice

	prompt "Default CPUFreq governor"

	default CPU_FREQ_DEFAULT_GOV_USERSPACE if ARM_SA1100_CPUFREQ || ARM_SA1110_CPUFREQ

drivers/cpufreq/Makefile

+4 −1
Original line number Diff line number Diff line
@@ -5,6 +5,9 @@ obj-$(CONFIG_CPU_FREQ) += cpufreq.o freq_table.o 
# CPUfreq stats

obj-$(CONFIG_CPU_FREQ_STAT)             += cpufreq_stats.o



# CPUfreq times

obj-$(CONFIG_CPU_FREQ_TIMES)		+= cpufreq_times.o



# CPUfreq governors

obj-$(CONFIG_CPU_FREQ_GOV_PERFORMANCE)	+= cpufreq_performance.o

obj-$(CONFIG_CPU_FREQ_GOV_POWERSAVE)	+= cpufreq_powersave.o

drivers/cpufreq/cpufreq.c

+3 −0
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 


#include <linux/cpu.h>

#include <linux/cpufreq.h>

#include <linux/cpufreq_times.h>

#include <linux/delay.h>

#include <linux/device.h>

#include <linux/init.h>
@@ -339,6 +340,7 @@ static void __cpufreq_notify_transition(struct cpufreq_policy *policy, 
			 (unsigned long)freqs->new, (unsigned long)freqs->cpu);

		trace_cpu_frequency(freqs->new, freqs->cpu);

		cpufreq_stats_record_transition(policy, freqs->new);

		cpufreq_times_record_transition(freqs);

		srcu_notifier_call_chain(&cpufreq_transition_notifier_list,

				CPUFREQ_POSTCHANGE, freqs);

		if (likely(policy) && likely(policy->cpu == freqs->cpu))
@@ -1287,6 +1289,7 @@ static int cpufreq_online(unsigned int cpu) 
			goto out_exit_policy;



		cpufreq_stats_create_table(policy);

		cpufreq_times_create_policy(policy);



		write_lock_irqsave(&cpufreq_driver_lock, flags);

		list_add(&policy->policy_list, &cpufreq_policy_list);

drivers/cpufreq/cpufreq_times.c

0 → 100644
+204 −0
Original line number Diff line number Diff line 
/* drivers/cpufreq/cpufreq_times.c

 *

 * Copyright (C) 2018 Google, Inc.

 *

 * This software is licensed under the terms of the GNU General Public

 * License version 2, as published by the Free Software Foundation, and

 * may be copied, distributed, and modified under those terms.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 */



#include <linux/cpufreq.h>

#include <linux/cpufreq_times.h>

#include <linux/jiffies.h>

#include <linux/sched.h>

#include <linux/seq_file.h>

#include <linux/slab.h>

#include <linux/spinlock.h>

#include <linux/threads.h>



static DEFINE_SPINLOCK(task_time_in_state_lock); /* task->time_in_state */



/**

 * struct cpu_freqs - per-cpu frequency information

 * @offset: start of these freqs' stats in task time_in_state array

 * @max_state: number of entries in freq_table

 * @last_index: index in freq_table of last frequency switched to

 * @freq_table: list of available frequencies

 */

struct cpu_freqs {

	unsigned int offset;

	unsigned int max_state;

	unsigned int last_index;

	unsigned int freq_table[0];

};



static struct cpu_freqs *all_freqs[NR_CPUS];



static unsigned int next_offset;



void cpufreq_task_times_init(struct task_struct *p)

{

	void *temp;

	unsigned long flags;

	unsigned int max_state;



	spin_lock_irqsave(&task_time_in_state_lock, flags);

	p->time_in_state = NULL;

	spin_unlock_irqrestore(&task_time_in_state_lock, flags);

	p->max_state = 0;



	max_state = READ_ONCE(next_offset);



	/* We use one array to avoid multiple allocs per task */

	temp = kcalloc(max_state, sizeof(p->time_in_state[0]), GFP_ATOMIC);

	if (!temp)

		return;



	spin_lock_irqsave(&task_time_in_state_lock, flags);

	p->time_in_state = temp;

	spin_unlock_irqrestore(&task_time_in_state_lock, flags);

	p->max_state = max_state;

}



/* Caller must hold task_time_in_state_lock */

static int cpufreq_task_times_realloc_locked(struct task_struct *p)

{

	void *temp;

	unsigned int max_state = READ_ONCE(next_offset);



	temp = krealloc(p->time_in_state, max_state * sizeof(u64), GFP_ATOMIC);

	if (!temp)

		return -ENOMEM;

	p->time_in_state = temp;

	memset(p->time_in_state + p->max_state, 0,

	       (max_state - p->max_state) * sizeof(u64));

	p->max_state = max_state;

	return 0;

}



void cpufreq_task_times_exit(struct task_struct *p)

{

	unsigned long flags;

	void *temp;



	spin_lock_irqsave(&task_time_in_state_lock, flags);

	temp = p->time_in_state;

	p->time_in_state = NULL;

	spin_unlock_irqrestore(&task_time_in_state_lock, flags);

	kfree(temp);

}



int proc_time_in_state_show(struct seq_file *m, struct pid_namespace *ns,

	struct pid *pid, struct task_struct *p)

{

	unsigned int cpu, i;

	u64 cputime;

	unsigned long flags;

	struct cpu_freqs *freqs;

	struct cpu_freqs *last_freqs = NULL;



	spin_lock_irqsave(&task_time_in_state_lock, flags);

	for_each_possible_cpu(cpu) {

		freqs = all_freqs[cpu];

		if (!freqs || freqs == last_freqs)

			continue;

		last_freqs = freqs;



		seq_printf(m, "cpu%u\n", cpu);

		for (i = 0; i < freqs->max_state; i++) {

			if (freqs->freq_table[i] == CPUFREQ_ENTRY_INVALID)

				continue;

			cputime = 0;

			if (freqs->offset + i < p->max_state &&

			    p->time_in_state)

				cputime = p->time_in_state[freqs->offset + i];

			seq_printf(m, "%u %lu\n", freqs->freq_table[i],

				   (unsigned long)nsec_to_clock_t(cputime));

		}

	}

	spin_unlock_irqrestore(&task_time_in_state_lock, flags);

	return 0;

}



void cpufreq_acct_update_power(struct task_struct *p, u64 cputime)

{

	unsigned long flags;

	unsigned int state;

	struct cpu_freqs *freqs = all_freqs[task_cpu(p)];



	if (!freqs || p->flags & PF_EXITING)

		return;



	state = freqs->offset + READ_ONCE(freqs->last_index);



	spin_lock_irqsave(&task_time_in_state_lock, flags);

	if ((state < p->max_state || !cpufreq_task_times_realloc_locked(p)) &&

	    p->time_in_state)

		p->time_in_state[state] += cputime;

	spin_unlock_irqrestore(&task_time_in_state_lock, flags);

}



void cpufreq_times_create_policy(struct cpufreq_policy *policy)

{

	int cpu, index;

	unsigned int count = 0;

	struct cpufreq_frequency_table *pos, *table;

	struct cpu_freqs *freqs;

	void *tmp;



	if (all_freqs[policy->cpu])

		return;



	table = policy->freq_table;

	if (!table)

		return;



	cpufreq_for_each_entry(pos, table)

		count++;



	tmp =  kzalloc(sizeof(*freqs) + sizeof(freqs->freq_table[0]) * count,

		       GFP_KERNEL);

	if (!tmp)

		return;



	freqs = tmp;

	freqs->max_state = count;



	index = cpufreq_frequency_table_get_index(policy, policy->cur);

	if (index >= 0)

		WRITE_ONCE(freqs->last_index, index);



	cpufreq_for_each_entry(pos, table)

		freqs->freq_table[pos - table] = pos->frequency;



	freqs->offset = next_offset;

	WRITE_ONCE(next_offset, freqs->offset + count);

	for_each_cpu(cpu, policy->related_cpus)

		all_freqs[cpu] = freqs;

}



void cpufreq_times_record_transition(struct cpufreq_freqs *freq)

{

	int index;

	struct cpu_freqs *freqs = all_freqs[freq->cpu];

	struct cpufreq_policy *policy;



	if (!freqs)

		return;



	policy = cpufreq_cpu_get(freq->cpu);

	if (!policy)

		return;



	index = cpufreq_frequency_table_get_index(policy, freq->new);

	if (index >= 0)

		WRITE_ONCE(freqs->last_index, index);



	cpufreq_cpu_put(policy);

}

fs/proc/base.c

+7 −0
Original line number Diff line number Diff line
@@ -93,6 +93,7 @@ 
#include <linux/sched/stat.h>

#include <linux/flex_array.h>

#include <linux/posix-timers.h>

#include <linux/cpufreq_times.h>

#ifdef CONFIG_HARDWALL

#include <asm/hardwall.h>

#endif
@@ -2989,6 +2990,9 @@ static const struct pid_entry tgid_base_stuff[] = { 
#ifdef CONFIG_LIVEPATCH

	ONE("patch_state",  S_IRUSR, proc_pid_patch_state),

#endif

#ifdef CONFIG_CPU_FREQ_TIMES

	ONE("time_in_state", 0444, proc_time_in_state_show),

#endif

};



static int proc_tgid_base_readdir(struct file *file, struct dir_context *ctx)
@@ -3376,6 +3380,9 @@ static const struct pid_entry tid_base_stuff[] = { 
#ifdef CONFIG_LIVEPATCH

	ONE("patch_state",  S_IRUSR, proc_pid_patch_state),

#endif

#ifdef CONFIG_CPU_FREQ_TIMES

	ONE("time_in_state", 0444, proc_time_in_state_show),

#endif

};



static int proc_tid_base_readdir(struct file *file, struct dir_context *ctx)