wmcpuload/src/cpu_linux.c

   1 /*
   2  * wmcpuload
   3  * GNU/Linux specific part
   4  *
   5  * Copyright (C) 2001, 2002, 2005 Seiichi SATO <ssato@sh.rim.or.jp>
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License as
   9  * published by the Free Software Foundation; either version 2 of the
  10  * License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  20  * 02111-1307, USA.
  21  */
  22
  23 #ifdef HAVE_CONFIG_H
  24 #include "config.h"
  25 #endif
  26
  27 #include <stdio.h>
  28 #include <unistd.h>
  29 #include <stdlib.h>
  30 #include <string.h>
  31 #include "cpu.h"
  32
  33 #include <dirent.h>
  34 #include <sys/types.h>
  35 #include <sys/stat.h>
  36 #include <linux/limits.h>
  37
  38 static int is_linux26;
  39
  40 static void
  41 skip_line(FILE *fp)
  42 {
  43         int c;
  44
  45         while ((c = fgetc(fp)) != '\n')
  46                 if (c == EOF) break;
  47 }
  48
  49 void
  50 cpu_init(void)
  51 {
  52         unsigned long long softirq;
  53         FILE *fp;
  54
  55         if (!(fp = fopen("/proc/stat", "r"))) {
  56                 perror("fopen");
  57                 exit(1);
  58         }
  59
  60         is_linux26 = fscanf(fp, "%*s  %*u %*u %*u %*u %*u %*u %llu",
  61                             &softirq);
  62
  63         fclose(fp);
  64
  65         return;
  66 }
  67
  68 /* returns current cpu usage in percent */
  69 int
  70 cpu_get_usage(cpu_options * opts)
  71 {
  72         unsigned long long user, nice, system, idle, iowait, irq, softirq;
  73         unsigned long long used, total;
  74         static unsigned long long pre_used = 0, pre_total = 0;
  75         int result;
  76
  77         FILE *fp;
  78         if (!(fp = fopen("/proc/stat", "r"))) {
  79                 perror("fopen");
  80                 exit(1);
  81         }
  82
  83
  84         if (opts->cpu_number == -1) {
  85                 if (is_linux26)
  86                         fscanf(fp, "%*s  %llu %llu %llu %llu %llu %llu %llu",
  87                                &user, &nice, &system, &idle, &iowait,
  88                                &irq, &softirq);
  89                 else
  90                         fscanf(fp, "%*s  %llu %llu %llu %llu",
  91                                &user, &nice, &system, &idle);
  92         } else {
  93                 char cpu_name[20];
  94                 int i;
  95
  96                 for (i = 0; i <= opts->cpu_number; i++)
  97                         skip_line(fp);
  98
  99                 if (is_linux26)
 100                         fscanf(fp, "%s  %llu %llu %llu %llu %llu %llu %llu",
 101                                cpu_name, &user, &nice, &system, &idle, &iowait,
 102                                &irq, &softirq);
 103                 else
 104                         fscanf(fp, "%s  %llu %llu %llu %llu",
 105                                cpu_name, &user, &nice, &system,
 106                                &idle);
 107
 108                 if (cpu_name[3] != '0' + opts->cpu_number) {
 109                         fprintf(stderr, "Could not find cpu%d.\n",
 110                                 opts->cpu_number);
 111                         exit(1);
 112                 }
 113         }
 114
 115         fclose(fp);
 116
 117         used = user + system;
 118         if (!opts->ignore_nice)
 119                 used += nice;
 120         total = user + nice + system + idle;
 121         if (is_linux26)
 122                 total += iowait + irq + softirq;
 123
 124         result = (100 * (double)(used - pre_used)) / (double)(total - pre_total);
 125
 126         pre_total = total;
 127         pre_used = used;
 128
 129         return result;
 130 }
 131