linux/kernel/time/timekeeping_debug.c
Jeff Layton 2a15385742
timekeeping: Add percpu counter for tracking floor swap events
The mgtime_floor value is a global variable for tracking the latest
fine-grained timestamp handed out. Because it's a global, track the
number of times that a new floor value is assigned.

Add a new percpu counter to the timekeeping code to track the number of
floor swap events that have occurred. A later patch will add a debugfs
file to display this counter alongside other stats involving multigrain
timestamps.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Randy Dunlap <rdunlap@infradead.org> # documentation bits
Link: https://lore.kernel.org/all/20241002-mgtime-v10-2-d1c4717f5284@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-10-10 10:20:46 +02:00

69 lines
1.6 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* debugfs file to track time spent in suspend
*
* Copyright (c) 2011, Google, Inc.
*/
#include <linux/debugfs.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/seq_file.h>
#include <linux/suspend.h>
#include <linux/time.h>
#include "timekeeping_internal.h"
#define NUM_BINS 32
/* Incremented every time mg_floor is updated */
DEFINE_PER_CPU(unsigned long, timekeeping_mg_floor_swaps);
static unsigned int sleep_time_bin[NUM_BINS] = {0};
static int tk_debug_sleep_time_show(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;
}
DEFINE_SHOW_ATTRIBUTE(tk_debug_sleep_time);
static int __init tk_debug_sleep_time_init(void)
{
debugfs_create_file("sleep_time", 0444, NULL, NULL,
&tk_debug_sleep_time_fops);
return 0;
}
late_initcall(tk_debug_sleep_time_init);
void tk_debug_account_sleep_time(const struct timespec64 *t)
{
/* Cap bin index so we don't overflow the array */
int bin = min(fls(t->tv_sec), NUM_BINS-1);
sleep_time_bin[bin]++;
pm_deferred_pr_dbg("Timekeeping suspended for %lld.%03lu seconds\n",
(s64)t->tv_sec, t->tv_nsec / NSEC_PER_MSEC);
}
unsigned long timekeeping_get_mg_floor_swaps(void)
{
unsigned long sum = 0;
int cpu;
for_each_possible_cpu(cpu)
sum += data_race(per_cpu(timekeeping_mg_floor_swaps, cpu));
return sum;
}