idlestat.c

   1 #define _GNU_SOURCE
   2 #include <err.h>
   3 #include <time.h>
   4 #include <stdio.h>
   5 #include <fcntl.h>
   6 #include <alloca.h>
   7 #include <unistd.h>
   8 #include <stdlib.h>
   9 #include <sys/time.h>
  10 #include <sys/sysinfo.h>
  11
  12 static double now (void)
  13 {
  14     struct timeval tv;
  15
  16     if (gettimeofday (&tv, NULL))
  17         err (1, "gettimeofday");
  18     return tv.tv_sec + tv.tv_usec * 1e-6;
  19 }
  20
  21 static void idlenow (int fd, int nprocs, double *p)
  22 {
  23     struct timeval tv;
  24     size_t n = nprocs * sizeof (tv);
  25     ssize_t m;
  26     struct timeval *buf;
  27     int i;
  28
  29     buf = alloca (n);
  30     if (!buf) errx (1, "alloca failed");
  31
  32     m = read (fd, buf, n);
  33     if (n - m) err (1, "read [n=%zu, m=%zi]", n, m);
  34
  35     for (i = 0; i < nprocs; ++i)
  36         p[i] = buf[i].tv_sec + buf[i].tv_usec * 1e-6;
  37 }
  38
  39 int main (int argc, char **argv)
  40 {
  41     int fd;
  42     int n = 1;
  43     int nprocs;
  44     double *idle;
  45     double *curr, *prev;
  46
  47     (void) argc;
  48     (void) argv;
  49
  50     if (argc > 1)
  51         n = atoi (argv[1]);
  52
  53     nprocs = get_nprocs ();
  54     if (nprocs <= 0) errx (1, "get_nprocs returned %d", nprocs);
  55
  56     idle = malloc (2 * nprocs * sizeof (idle[0]));
  57     if (!idle) errx (1, "malloc %zu failed", 2 * nprocs * sizeof (idle[0]));
  58
  59     fd = open ("/dev/itc", O_RDONLY);
  60     if (fd < 0) err (1, "open /dev/itc");
  61
  62     idlenow (fd, nprocs, idle);
  63
  64     curr = &idle[nprocs];
  65     prev = idle;
  66     setbuf (stdout, NULL);
  67
  68     for (;;) {
  69         int i;
  70         double s, e, d, *t, a = 0.0, ai = 0.0;
  71
  72         idlenow (fd, nprocs, prev);
  73         s = now ();
  74         sleep (n);
  75         idlenow (fd, nprocs, curr);
  76         e = now ();
  77         d = e - s;
  78
  79         for (i = 0; i < nprocs; ++i) {
  80             double di = curr[i] - prev[i];
  81
  82             /* printf ("\rcpu%d - %.2f", i, 100.0 * (1.0 - di / d)); */
  83             /* printf ("cpu%d - %6.2f\n", i, 100.0 * (1.0 - di / d)); */
  84             a += d;
  85             ai += di;
  86             printf ("%7.2f", 100.0 * (1.0 - di / d));
  87             if (i < nprocs) fputc (' ', stdout);
  88         }
  89         if (i > 1) {
  90             printf ("%6.2f\n", 100.0 * (1.0 - ai / a));
  91         }
  92         else {
  93             fputc ('\n', stdout);
  94         }
  95
  96         t = curr;
  97         curr = prev;
  98         prev = t;
  99     }
 100 }