git.sur5r.net Git - i3/i3status/blob - src/print_cpu_usage.c

   1 // vim:sw=8:sts=8:ts=8:expandtab
   2 #include <stdlib.h>
   3 #include <limits.h>
   4 #include <stdio.h>
   5 #include <string.h>
   6
   7 #include "i3status.h"
   8
   9 static int prev_total = 0;
  10 static int prev_idle  = 0;
  11
  12 /*
  13  * Reads the CPU utilization from /proc/stat and returns the usage as a
  14  * percentage.
  15  *
  16  */
  17 void print_cpu_usage(const char *format) {
  18         const char *walk;
  19         char buf[1024];
  20         int curr_user, curr_nice, curr_system, curr_idle, curr_total;
  21         int diff_idle, diff_total, diff_usage;
  22
  23 #if defined(LINUX)
  24         static char statpath[512];
  25         strcpy(statpath, "/proc/stat");
  26         if (!slurp(statpath, buf, sizeof(buf)))
  27                 die("could not read %s\n", statpath);
  28
  29         if (sscanf(buf, "cpu %d %d %d %d", &curr_user, &curr_nice, &curr_system, &curr_idle) != 4)
  30                 die("could not read cpu utilization\n");
  31
  32         curr_total = curr_user + curr_nice + curr_system + curr_idle;
  33         diff_idle  = curr_idle - prev_idle;
  34         diff_total = curr_total - prev_total;
  35         diff_usage = (1000 * (diff_total - diff_idle)/diff_total + 5)/10;
  36         prev_total = curr_total;
  37         prev_idle  = curr_idle;
  38 #endif
  39         for (walk = format; *walk != '\0'; walk++) {
  40                 if (*walk != '%') {
  41                         putchar(*walk);
  42                         continue;
  43                 }
  44
  45                 if (strncmp(walk+1, "usage", strlen("usage")) == 0) {
  46                         printf("%02d%%", diff_usage);
  47                         walk += strlen("usage");
  48                 }
  49         }
  50 }