LXR linux/kernel/time/timekeeping

   1/*
   2 * debugfs file to track time spent in suspend
   3 *
   4 * Copyright (c) 2011, Google, Inc.
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License as published by
   8 * the Free Software Foundation; either version 2 of the License, or
   9 * (at your option) any later version.
  10 *
  11 * This program is distributed in the hope that it will be useful, but WITHOUT
  12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  14 * more details.
  15 */
  16
  17#include <linux/debugfs.h>
  18#include <linux/err.h>
  19#include <linux/init.h>
  20#include <linux/kernel.h>
  21#include <linux/seq_file.h>
  22#include <linux/suspend.h>
  23#include <linux/time.h>
  24
  25#include "timekeeping_internal.h"
  26
  27#define NUM_BINS 32
  28
  29static unsigned int sleep_time_bin[NUM_BINS] = {0};
  30
  31static int tk_debug_show_sleep_time(struct seq_file *s, void *data)
  32{
  33        unsigned int bin;
  34        seq_puts(s, "      time (secs)        count\n");
  35        seq_puts(s, "------------------------------\n");
  36        for (bin = 0; bin < 32; bin++) {
  37                if (sleep_time_bin[bin] == 0)
  38                        continue;
  39                seq_printf(s, "%10u - %-10u %4u\n",
  40                        bin ? 1 << (bin - 1) : 0, 1 << bin,
  41                                sleep_time_bin[bin]);
  42        }
  43        return 0;
  44}
  45
  46static int tk_debug_sleep_time_open(struct inode *inode, struct file *file)
  47{
  48        return single_open(file, tk_debug_show_sleep_time, NULL);
  49}
  50
  51static const struct file_operations tk_debug_sleep_time_fops = {
  52        .open           = tk_debug_sleep_time_open,
  53        .read           = seq_read,
  54        .llseek         = seq_lseek,
  55        .release        = single_release,
  56};
  57
  58static int __init tk_debug_sleep_time_init(void)
  59{
  60        struct dentry *d;
  61
  62        d = debugfs_create_file("sleep_time", 0444, NULL, NULL,
  63                &tk_debug_sleep_time_fops);
  64        if (!d) {
  65                pr_err("Failed to create sleep_time debug file\n");
  66                return -ENOMEM;
  67        }
  68
  69        return 0;
  70}
  71late_initcall(tk_debug_sleep_time_init);
  72
  73void tk_debug_account_sleep_time(const struct timespec64 *t)
  74{
  75        /* Cap bin index so we don't overflow the array */
  76        int bin = min(fls(t->tv_sec), NUM_BINS-1);
  77
  78        sleep_time_bin[bin]++;
  79        pm_deferred_pr_dbg("Timekeeping suspended for %lld.%03lu seconds\n",
  80                           (s64)t->tv_sec, t->tv_nsec / NSEC_PER_MSEC);
  81}
  82
  83