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