rt/tst-cputimer2.c

   1 /* Tests for POSIX timer implementation using thread CPU clock.  */
   2
   3 #include <unistd.h>
   4
   5 #if _POSIX_THREADS && defined _POSIX_CPUTIME
   6
   7 #include <errno.h>
   8 #include <stdio.h>
   9 #include <stdlib.h>
  10 #include <string.h>
  11 #include <fcntl.h>
  12 #include <time.h>
  13 #include <pthread.h>
  14
  15 #include <support/xunistd.h>
  16
  17 static clockid_t worker_thread_clock;
  18
  19 #define TEST_CLOCK worker_thread_clock
  20 #define TEST_CLOCK_MISSING(clock) \
  21   (setup_test () ? "thread CPU clock timer support" : NULL)
  22
  23 /* This function is intended to rack up both user and system time.  */
  24 static void *
  25 chew_cpu (void *arg)
  26 {
  27   while (1)
  28     {
  29       static volatile char buf[4096];
  30       for (int i = 0; i < 100; ++i)
  31         for (size_t j = 0; j < sizeof buf; ++j)
  32           buf[j] = 0xaa;
  33       int nullfd = open ("/dev/null", O_WRONLY);
  34       for (int i = 0; i < 100; ++i)
  35         for (size_t j = 0; j < sizeof buf; ++j)
  36           buf[j] = 0xbb;
  37       xwrite (nullfd, (char *) buf, sizeof buf);
  38       close (nullfd);
  39     }
  40
  41   return NULL;
  42 }
  43
  44 static int
  45 setup_test (void)
  46 {
  47   /* Test timers on a thread CPU clock by having a worker thread eating
  48      CPU.  First make sure we can make such timers at all.  */
  49
  50   pthread_t th;
  51   int e = pthread_create (&th, NULL, chew_cpu, NULL);
  52   if (e != 0)
  53     {
  54       printf ("pthread_create: %s\n", strerror (e));
  55       exit (1);
  56     }
  57
  58   e = pthread_getcpuclockid (th, &worker_thread_clock);
  59   if (e == EPERM || e == ENOENT || e == ENOTSUP)
  60     {
  61       puts ("pthread_getcpuclockid does not support other threads");
  62       return 1;
  63     }
  64   if (e != 0)
  65     {
  66       printf ("pthread_getcpuclockid: %s\n", strerror (e));
  67       exit (1);
  68     }
  69
  70   timer_t t;
  71   if (timer_create (TEST_CLOCK, NULL, &t) != 0)
  72     {
  73       printf ("timer_create: %m\n");
  74       return 1;
  75     }
  76   timer_delete (t);
  77
  78   return 0;
  79 }
  80
  81 #else
  82 # define TEST_CLOCK_MISSING(clock) "process clocks"
  83 #endif
  84
  85 #include "tst-timer4.c"