kernel/time/timekeeping_debug.c

   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
  24 static unsigned int sleep_time_bin[32] = {0};
  25
  26 static 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
  41 static 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
  46 static 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
  53 static 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 }
  66 late_initcall(tk_debug_sleep_time_init);
  67
  68 void tk_debug_account_sleep_time(struct timespec *t)
  69 {
  70         sleep_time_bin[fls(t->tv_sec)]++;
  71 }
  72