Intensive test for POSIX barriers.

1 files changed, 132 insertions, 0 deletions

diff --git a/linuxthreads/Examples/ex14.c b/linuxthreads/Examples/ex14.c
new file mode 100644
index 0000000..4e6e10d
--- /dev/null
+++ b/linuxthreads/Examples/ex14.c
@@ -0,0 +1,132 @@
+/* Test of POSIX barriers.  */
+
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define NTHREADS 20
+
+#define ROUNDS 20
+
+static pthread_barrier_t barriers[NTHREADS];
+
+static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
+static int counters[NTHREADS];
+static int serial[NTHREADS];
+
+static void *
+worker (void *arg)
+{
+  void *result = NULL;
+  int nr = (int) arg;
+  int i;
+
+  for (i = 0; i < ROUNDS; ++i)
+    {
+      int j;
+      int retval;
+
+      if (nr == 0)
+	{
+	  memset (counters, '\0', sizeof (counters));
+	  memset (serial, '\0', sizeof (serial));
+	}
+
+      retval = pthread_barrier_wait (&barriers[NTHREADS - 1]);
+      if (retval != 0 && retval != PTHREAD_BARRIER_SERIAL_THREAD)
+	{
+	  printf ("thread %d failed to wait for all the others\n", nr);
+	  result = (void *) 1;
+	}
+
+      for (j = nr; j < NTHREADS; ++j)
+	{
+	  /* Increment the counter for this round.  */
+	  pthread_mutex_lock (&lock);
+	  ++counters[j];
+	  pthread_mutex_unlock (&lock);
+
+	  /* Wait for the rest.  */
+	  retval = pthread_barrier_wait (&barriers[j]);
+
+	  /* Test the result.  */
+	  if (nr == 0 && counters[j] != j + 1)
+	    {
+	      printf ("barrier in round %d released but count is %d\n",
+		      j, counters[j]);
+	      result = (void *) 1;
+	    }
+
+	  if (retval != 0)
+	    {
+	      if (retval != PTHREAD_BARRIER_SERIAL_THREAD)
+		{
+		  printf ("thread %d in round %d has nonzero return value != PTHREAD_BARRIER_SERIAL_THREAD\n",
+			  nr, j);
+		  result = (void *) 1;
+		}
+	      else
+		{
+		  pthread_mutex_lock (&lock);
+		  ++serial[j];
+		  pthread_mutex_unlock (&lock);
+		}
+	    }
+
+	  /* Wait for the rest again.  */
+	  retval = pthread_barrier_wait (&barriers[j]);
+
+	  /* Now we can check whether exactly one thread was serializing.  */
+	  if (nr == 0 && serial[j] != 1)
+	    {
+	      printf ("not exactly one serial thread in round %d\n", j);
+	      result = (void *) 1;
+	    }
+	}
+    }
+
+  return result;
+}
+
+
+#define TEST_FUNCTION do_test ()
+int
+do_test (void)
+{
+  pthread_t threads[NTHREADS];
+  int i;
+  void *res;
+  int result = 0;
+
+  /* Initialized the barrier variables.  */
+  for (i = 0; i < NTHREADS; ++i)
+    if (pthread_barrier_init (&barriers[i], NULL, i + 1) != 0)
+      {
+	printf ("Failed to initialize barrier %d\n", i);
+	exit (1);
+      }
+
+  /* Start the threads.  */
+  for (i = 0; i < NTHREADS; ++i)
+    if (pthread_create (&threads[i], NULL, worker, (void *) i) != 0)
+      {
+	printf ("Failed to start thread %d\n", i);
+	exit (1);
+      }
+
+  /* And wait for them.  */
+  for (i = 0; i < NTHREADS; ++i)
+    if (pthread_join (threads[i], &res) != 0 || res != NULL)
+      {
+	printf ("thread %d returned a failure\n", i);
+	result = 1;
+      }
+
+  if (result == 0)
+    puts ("all OK");
+
+  return result;
+}
+
+#include "../test-skeleton.c"