kernel/time/timekeeping_debug.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * debugfs file to track time spent in suspend
   4  *
   5  * Copyright (c) 2011, Google, Inc.
   6  */
   7
   8 #include <linux/debugfs.h>
   9 #include <linux/err.h>
  10 #include <linux/init.h>
  11 #include <linux/kernel.h>
  12 #include <linux/seq_file.h>
  13 #include <linux/suspend.h>
  14 #include <linux/time.h>
  15
  16 #include "timekeeping_internal.h"
  17
  18 #define NUM_BINS 32
  19
  20 /* Incremented every time mg_floor is updated */
  21 DEFINE_PER_CPU(unsigned long, timekeeping_mg_floor_swaps);
  22
  23 static unsigned int sleep_time_bin[NUM_BINS] = {0};
  24
  25 static int tk_debug_sleep_time_show(struct seq_file *s, void *data)
  26 {
  27         unsigned int bin;
  28         seq_puts(s, "      time (secs)        count\n");
  29         seq_puts(s, "------------------------------\n");
  30         for (bin = 0; bin < 32; bin++) {
  31                 if (sleep_time_bin[bin] == 0)
  32                         continue;
  33                 seq_printf(s, "%10u - %-10u %4u\n",
  34                         bin ? 1 << (bin - 1) : 0, 1 << bin,
  35                                 sleep_time_bin[bin]);
  36         }
  37         return 0;
  38 }
  39 DEFINE_SHOW_ATTRIBUTE(tk_debug_sleep_time);
  40
  41 static int __init tk_debug_sleep_time_init(void)
  42 {
  43         debugfs_create_file("sleep_time", 0444, NULL, NULL,
  44                             &tk_debug_sleep_time_fops);
  45         return 0;
  46 }
  47 late_initcall(tk_debug_sleep_time_init);
  48
  49 void tk_debug_account_sleep_time(const struct timespec64 *t)
  50 {
  51         /* Cap bin index so we don't overflow the array */
  52         int bin = min(fls(t->tv_sec), NUM_BINS-1);
  53
  54         sleep_time_bin[bin]++;
  55         pm_deferred_pr_dbg("Timekeeping suspended for %lld.%03lu seconds\n",
  56                            (s64)t->tv_sec, t->tv_nsec / NSEC_PER_MSEC);
  57 }
  58
  59 unsigned long timekeeping_get_mg_floor_swaps(void)
  60 {
  61         unsigned long sum = 0;
  62         int cpu;
  63
  64         for_each_possible_cpu(cpu)
  65                 sum += data_race(per_cpu(timekeeping_mg_floor_swaps, cpu));
  66
  67         return sum;
  68 }