import gdb-1999-10-18 snapshot

gdb/testsuite/gdb.threads/linux-dp.c

@@ -0,0 +1,205 @@
+/* linux-dp.c --- dining philosophers, on LinuxThreads
+   Jim Blandy <jimb@cygnus.com> --- March 1999  */
+
+/* It's okay to edit this file and shift line numbers around.  The
+   tests use gdb_get_line_number to find source locations, so they
+   don't depend on having certain line numbers in certain places.  */
+
+#include <stdarg.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <pthread.h>
+#include <sys/time.h>
+#include <sys/types.h>
+
+/* The number of philosophers at the table.  */
+int num_philosophers;
+
+/* Mutex ordering -
+   If you want to lock a mutex M, all the mutexes you have locked
+   already must appear before M on this list.
+
+   fork_mutex[0]
+   fork_mutex[1]
+   ...
+   fork_mutex[num_philosophers - 1]
+   stdout_mutex
+   random_mutex
+*/
+
+/* You must hold this mutex while writing to stdout.  */
+pthread_mutex_t stdout_mutex;
+
+/* You must hold this mutex while calling any of the random number
+   generation routines.  */
+pthread_mutex_t random_mutex;
+
+/* array of mutexes, one for each fork; fork_mutex[i] is to the left
+   of philosopher i.  A philosopher is holding fork i iff his/her
+   thread has locked fork_mutex[i].  */
+pthread_mutex_t *fork_mutex;
+
+/* array of threads, one representing each philosopher.  */
+pthread_t *philosophers;
+
+void *
+xmalloc (size_t n)
+{
+  void *p = malloc (n);
+
+  if (! p)
+    {
+      fprintf (stderr, "out of memory\n");
+      exit (2);
+    }
+
+  return p;
+}
+
+void
+shared_printf (char *format, ...)
+{
+  va_list ap;
+
+  va_start (ap, format);
+  pthread_mutex_lock (&stdout_mutex);
+  vprintf (format, ap);
+  pthread_mutex_unlock (&stdout_mutex);
+  va_end (ap);
+}
+
+int 
+shared_random ()
+{
+  static unsigned int seed;
+  int result;
+
+  pthread_mutex_lock (&random_mutex);
+  result = rand_r (&seed);
+  pthread_mutex_unlock (&random_mutex);
+  return result;
+}
+
+void
+my_usleep (long usecs)
+{
+  struct timeval timeout;
+  
+  timeout.tv_sec = usecs / 1000000;
+  timeout.tv_usec = usecs % 1000000;
+
+  select (0, 0, 0, 0, &timeout);
+}
+
+void
+random_delay ()
+{
+  my_usleep ((shared_random () % 2000) * 100);
+}
+
+void
+print_philosopher (int n, char left, char right)
+{
+  int i;
+
+  shared_printf ("%*s%c %d %c\n", (n * 4) + 2, "", left, n, right);
+}
+
+void *
+philosopher (void *data)
+{
+  int n = * (int *) data;
+
+  print_philosopher (n, '_', '_');
+
+#if 1
+  if (n == num_philosophers - 1)
+    for (;;)
+      {
+	/* The last philosopher is different.  He goes for his right
+	   fork first, so there is no cycle in the mutex graph.  */
+
+	/* Grab the right fork.  */
+	pthread_mutex_lock (&fork_mutex[(n + 1) % num_philosophers]);
+	print_philosopher (n, '_', '!');
+	random_delay ();
+
+	/* Then grab the left fork. */
+	pthread_mutex_lock (&fork_mutex[n]);
+	print_philosopher (n, '!', '!');
+	random_delay ();
+
+	print_philosopher (n, '_', '_');
+	pthread_mutex_unlock (&fork_mutex[n]);
+	pthread_mutex_unlock (&fork_mutex[(n + 1) % num_philosophers]);
+	random_delay ();
+      }
+  else
+#endif
+    for (;;)
+      {
+	/* Grab the left fork. */
+	pthread_mutex_lock (&fork_mutex[n]);
+	print_philosopher (n, '!', '_');
+	random_delay ();
+
+	/* Then grab the right fork.  */
+	pthread_mutex_lock (&fork_mutex[(n + 1) % num_philosophers]);
+	print_philosopher (n, '!', '!');
+	random_delay ();
+
+	print_philosopher (n, '_', '_');
+	pthread_mutex_unlock (&fork_mutex[n]);
+	pthread_mutex_unlock (&fork_mutex[(n + 1) % num_philosophers]);
+	random_delay ();
+      }
+}
+
+int
+main (int argc, char **argv)
+{
+  num_philosophers = 5;
+
+  /* Set up the mutexes.  */
+  {
+    pthread_mutexattr_t ma;
+    int i;
+
+    pthread_mutexattr_init (&ma);
+    pthread_mutex_init (&stdout_mutex, &ma);
+    pthread_mutex_init (&random_mutex, &ma);
+    fork_mutex = xmalloc (num_philosophers * sizeof (fork_mutex[0]));
+    for (i = 0; i < num_philosophers; i++)
+      pthread_mutex_init (&fork_mutex[i], &ma);
+    pthread_mutexattr_destroy (&ma);
+  }
+
+  /* Set off the threads.  */
+  {
+    int i;
+    int *numbers = xmalloc (num_philosophers * sizeof (*numbers));
+    pthread_attr_t ta;
+
+    philosophers = xmalloc (num_philosophers * sizeof (*philosophers));
+
+    pthread_attr_init (&ta);
+    
+    for (i = 0; i < num_philosophers; i++)
+      {
+	numbers[i] = i;
+	/* linuxthreads.exp: create philosopher */
+	pthread_create (&philosophers[i], &ta, philosopher, &numbers[i]);
+      }
+    
+    pthread_attr_destroy (&ta);
+  }
+
+  /* linuxthreads.exp: info threads 2 */
+  sleep (1000000);
+
+  /* Drink yourself into oblivion.  */
+  for (;;)
+    sleep (1000000);
+
+  return 0;
+}