Commit 7854c752 authored by Viresh Kumar's avatar Viresh Kumar Committed by Rafael J. Wysocki
Browse files

cpufreq: stats: Use local_clock() instead of jiffies 



local_clock() has better precision and accuracy as compared to jiffies,
lets use it for time management in cpufreq stats.

Signed-off-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 90ac908a

drivers/cpufreq/cpufreq_stats.c

+8 −8
Original line number Diff line number Diff line
@@ -9,9 +9,9 @@ 
#include <linux/cpu.h>

#include <linux/cpufreq.h>

#include <linux/module.h>

#include <linux/sched/clock.h>

#include <linux/slab.h>





struct cpufreq_stats {

	unsigned int total_trans;

	unsigned long long last_time;
@@ -30,7 +30,7 @@ struct cpufreq_stats { 
static void cpufreq_stats_update(struct cpufreq_stats *stats,

				 unsigned long long time)

{

	unsigned long long cur_time = get_jiffies_64();

	unsigned long long cur_time = local_clock();



	stats->time_in_state[stats->last_index] += cur_time - time;

	stats->last_time = cur_time;
@@ -42,7 +42,7 @@ static void cpufreq_stats_reset_table(struct cpufreq_stats *stats) 


	memset(stats->time_in_state, 0, count * sizeof(u64));

	memset(stats->trans_table, 0, count * count * sizeof(int));

	stats->last_time = get_jiffies_64();

	stats->last_time = local_clock();

	stats->total_trans = 0;



	/* Adjust for the time elapsed since reset was requested */
@@ -82,18 +82,18 @@ static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf) 
				 * before the reset_pending read above.

				 */

				smp_rmb();

				time = get_jiffies_64() - READ_ONCE(stats->reset_time);

				time = local_clock() - READ_ONCE(stats->reset_time);

			} else {

				time = 0;

			}

		} else {

			time = stats->time_in_state[i];

			if (i == stats->last_index)

				time += get_jiffies_64() - stats->last_time;

				time += local_clock() - stats->last_time;

		}



		len += sprintf(buf + len, "%u %llu\n", stats->freq_table[i],

			       jiffies_64_to_clock_t(time));

			       nsec_to_clock_t(time));

	}

	return len;

}
@@ -109,7 +109,7 @@ static ssize_t store_reset(struct cpufreq_policy *policy, const char *buf, 
	 * Defer resetting of stats to cpufreq_stats_record_transition() to

	 * avoid races.

	 */

	WRITE_ONCE(stats->reset_time, get_jiffies_64());

	WRITE_ONCE(stats->reset_time, local_clock());

	/*

	 * The memory barrier below is to prevent the readers of reset_time from

	 * seeing a stale or partially updated value.
@@ -249,7 +249,7 @@ void cpufreq_stats_create_table(struct cpufreq_policy *policy) 
			stats->freq_table[i++] = pos->frequency;



	stats->state_num = i;

	stats->last_time = get_jiffies_64();

	stats->last_time = local_clock();

	stats->last_index = freq_table_get_index(stats, policy->cur);



	policy->stats = stats;

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