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/suspend.h>
  23 #include <linux/time.h>
  24
  25 #include "timekeeping_internal.h"
  26
  27 #define NUM_BINS 32
  28
  29 static unsigned int sleep_time_bin[NUM_BINS] = {0};
  30
  31 static 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
  46 static 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
  51 static 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
  58 static 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 }
  71 late_initcall(tk_debug_sleep_time_init);
  72
  73 void tk_debug_account_sleep_time(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