diff --git a/tests/test-lock.c b/tests/test-lock.c
index 095511e..336daeb 100644
--- a/tests/test-lock.c
+++ b/tests/test-lock.c
@@ -17,6 +17,7 @@
 /* Written by Bruno Haible <address@hidden>, 2005.  */
 
 #include <config.h>
+#include <unistd.h>
 
 #if USE_POSIX_THREADS || USE_SOLARIS_THREADS || USE_PTH_THREADS || USE_WINDOWS_THREADS
 
@@ -41,10 +42,10 @@
 /* Which tests to perform.
    Uncomment some of these, to verify that all tests crash if no locking
    is enabled.  */
-#define DO_TEST_LOCK 1
+#define DO_TEST_LOCK 0
 #define DO_TEST_RWLOCK 1
-#define DO_TEST_RECURSIVE_LOCK 1
-#define DO_TEST_ONCE 1
+#define DO_TEST_RECURSIVE_LOCK 0
+#define DO_TEST_ONCE 0
 
 /* Whether to help the scheduler through explicit yield().
    Uncomment this to see if the operating system has a fair scheduler.  */
@@ -58,10 +59,10 @@
 #define USE_VOLATILE 0
 
 /* Whether to print debugging messages.  */
-#define ENABLE_DEBUGGING 0
+#define ENABLE_DEBUGGING 1
 
 /* Number of simultaneous threads.  */
-#define THREAD_COUNT 10
+#define THREAD_COUNT 3
 
 /* Number of operations performed in each thread.
    This is quite high, because with a smaller count, say 5000, we often get
@@ -312,11 +313,20 @@ static struct atomic_int rwlock_checker_done;
 static void *
 rwlock_checker_thread (void *arg)
 {
+  int tid = *((int *)arg);
   while (get_atomic_int_value (&rwlock_checker_done) == 0)
     {
       dbgprintf ("Checker %p before check rdlock\n", gl_thread_self_pointer ());
       gl_rwlock_rdlock (my_rwlock);
       check_accounts ();
+
+      /* Wait about (THREAD_COUNT - 1) seconds in critical section, so (if
+       * writers are not prefered) at least one reader has ackquired rdonly
+       * lock and writers starve. */
+      while (time(NULL) % THREAD_COUNT != tid)
+        usleep(100000);
+      usleep(800000);
+
       gl_rwlock_unlock (my_rwlock);
       dbgprintf ("Checker %p after  check unlock\n", gl_thread_self_pointer ());
 
@@ -342,7 +352,7 @@ test_rwlock (void)
 
   /* Spawn the threads.  */
   for (i = 0; i < THREAD_COUNT; i++)
-    checkerthreads[i] = gl_thread_create (rwlock_checker_thread, NULL);
+    checkerthreads[i] = gl_thread_create (rwlock_checker_thread, &i);
   for (i = 0; i < THREAD_COUNT; i++)
     threads[i] = gl_thread_create (rwlock_mutator_thread, NULL);