Commit 5c83545f authored by Colin Cross's avatar Colin Cross Committed by John Stultz
Browse files

power: Add option to log time spent in suspend 



Below is a patch from android kernel that maintains a histogram of
suspend times. Please review and provide feedback.

Statistices on the time spent in suspend are kept in
/sys/kernel/debug/sleep_time.

Cc: Android Kernel Team <kernel-team@android.com>
Cc: Colin Cross <ccross@android.com>
Cc: Todd Poynor <toddpoynor@google.com>
Cc: San Mehat <san@google.com>
Cc: Benoit Goby <benoit@android.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarColin Cross <ccross@android.com>
Signed-off-by: default avatarTodd Poynor <toddpoynor@google.com>
[zoran.markovic@linaro.org: Re-formatted suspend time table to better
fit expected values. Moved accounting of suspend time into timekeeping
core. Removed CONFIG_SUSPEND_TIME flag and made the feature conditional
on CONFIG_DEBUG_FS. Changed the file name to sleep_time to better fit
terminology in timekeeping core. Changed seq_printf to seq_puts. Tweaked
commit message]
Signed-off-by: default avatarZoran Markovic <zoran.markovic@linaro.org>
Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
parent 11ffa9d6

kernel/time/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -7,3 +7,4 @@ obj-$(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST) += tick-broadcast.o 
obj-$(CONFIG_TICK_ONESHOT)			+= tick-oneshot.o

obj-$(CONFIG_TICK_ONESHOT)			+= tick-sched.o

obj-$(CONFIG_TIMER_STATS)			+= timer_stats.o

obj-$(CONFIG_DEBUG_FS)				+= timekeeping_debug.o

kernel/time/timekeeping.c

+2 −0
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ 


#include "tick-internal.h"

#include "ntp_internal.h"

#include "timekeeping_internal.h"



static struct timekeeper timekeeper;

static DEFINE_RAW_SPINLOCK(timekeeper_lock);
@@ -851,6 +852,7 @@ static void __timekeeping_inject_sleeptime(struct timekeeper *tk, 
	tk_xtime_add(tk, delta);

	tk_set_wall_to_mono(tk, timespec_sub(tk->wall_to_monotonic, *delta));

	tk_set_sleep_time(tk, timespec_add(tk->total_sleep_time, *delta));

	tk_debug_account_sleep_time(delta);

}



/**

kernel/time/timekeeping_debug.c

0 → 100644
+72 −0
Original line number Diff line number Diff line 
/*

 * debugfs file to track time spent in suspend

 *

 * Copyright (c) 2011, Google, Inc.

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * 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/debugfs.h>

#include <linux/err.h>

#include <linux/init.h>

#include <linux/kernel.h>

#include <linux/seq_file.h>

#include <linux/time.h>



static unsigned int sleep_time_bin[32] = {0};



static int tk_debug_show_sleep_time(struct seq_file *s, void *data)

{

	unsigned int bin;

	seq_puts(s, "      time (secs)        count\n");

	seq_puts(s, "------------------------------\n");

	for (bin = 0; bin < 32; bin++) {

		if (sleep_time_bin[bin] == 0)

			continue;

		seq_printf(s, "%10u - %-10u %4u\n",

			bin ? 1 << (bin - 1) : 0, 1 << bin,

				sleep_time_bin[bin]);

	}

	return 0;

}



static int tk_debug_sleep_time_open(struct inode *inode, struct file *file)

{

	return single_open(file, tk_debug_show_sleep_time, NULL);

}



static const struct file_operations tk_debug_sleep_time_fops = {

	.open		= tk_debug_sleep_time_open,

	.read		= seq_read,

	.llseek		= seq_lseek,

	.release	= single_release,

};



static int __init tk_debug_sleep_time_init(void)

{

	struct dentry *d;



	d = debugfs_create_file("sleep_time", 0444, NULL, NULL,

		&tk_debug_sleep_time_fops);

	if (!d) {

		pr_err("Failed to create sleep_time debug file\n");

		return -ENOMEM;

	}



	return 0;

}

late_initcall(tk_debug_sleep_time_init);



void tk_debug_account_sleep_time(struct timespec *t)

{

	sleep_time_bin[fls(t->tv_sec)]++;

}

kernel/time/timekeeping_internal.h

0 → 100644
+14 −0
Original line number Diff line number Diff line 
#ifndef _TIMEKEEPING_INTERNAL_H

#define _TIMEKEEPING_INTERNAL_H

/*

 * timekeeping debug functions

 */

#include <linux/time.h>



#ifdef CONFIG_DEBUG_FS

extern void tk_debug_account_sleep_time(struct timespec *t);

#else

#define tk_debug_account_sleep_time(x)

#endif



#endif /* _TIMEKEEPING_INTERNAL_H */

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