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/time.h>
  23
  24static unsigned int sleep_time_bin[32] = {0};
  25
  26static int tk_debug_show_sleep_time(struct seq_file *s, void *data)
  27{
  28        unsigned int bin;
  29        seq_puts(s, "      time (secs)        count\n");
  30        seq_puts(s, "------------------------------\n");
  31        for (bin = 0; bin < 32; bin++) {
  32                if (sleep_time_bin[bin] == 0)
  33                        continue;
  34                seq_printf(s, "%10u - %-10u %4u\n",
  35                        bin ? 1 << (bin - 1) : 0, 1 << bin,
  36                                sleep_time_bin[bin]);
  37        }
  38        return 0;
  39}
  40
  41static int tk_debug_sleep_time_open(struct inode *inode, struct file *file)
  42{
  43        return single_open(file, tk_debug_show_sleep_time, NULL);
  44}
  45
  46static const struct file_operations tk_debug_sleep_time_fops = {
  47        .open           = tk_debug_sleep_time_open,
  48        .read           = seq_read,
  49        .llseek         = seq_lseek,
  50        .release        = single_release,
  51};
  52
  53static int __init tk_debug_sleep_time_init(void)
  54{
  55        struct dentry *d;
  56
  57        d = debugfs_create_file("sleep_time", 0444, NULL, NULL,
  58                &tk_debug_sleep_time_fops);
  59        if (!d) {
  60                pr_err("Failed to create sleep_time debug file\n");
  61                return -ENOMEM;
  62        }
  63
  64        return 0;
  65}
  66late_initcall(tk_debug_sleep_time_init);
  67
  68void tk_debug_account_sleep_time(struct timespec *t)
  69{
  70        sleep_time_bin[fls(t->tv_sec)]++;
  71}
  72
  73