diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py
index dc94603..e309a54 100644
--- a/Lib/test/test_threading.py
+++ b/Lib/test/test_threading.py
@@ -30,32 +30,28 @@
         self.nrunning = nrunning
 
     def run(self):
-        delay = random.random() * 2
+        delay = random.random() / 10000.0
         if verbose:
-            print 'task', self.getName(), 'will run for', delay, 'sec'
+            print 'task %s will run for %.1f usec' % (
+                self.getName(), delay * 1e6)
 
-        self.sema.acquire()
+        with self.sema:
+            with self.mutex:
+                self.nrunning.inc()
+                if verbose:
+                    print self.nrunning.get(), 'tasks are running'
+                self.testcase.assert_(self.nrunning.get() <= 3)
 
-        self.mutex.acquire()
-        self.nrunning.inc()
-        if verbose:
-            print self.nrunning.get(), 'tasks are running'
-        self.testcase.assert_(self.nrunning.get() <= 3)
-        self.mutex.release()
+            time.sleep(delay)
+            if verbose:
+                print 'task', self.getName(), 'done'
 
-        time.sleep(delay)
-        if verbose:
-            print 'task', self.getName(), 'done'
-
-        self.mutex.acquire()
-        self.nrunning.dec()
-        self.testcase.assert_(self.nrunning.get() >= 0)
-        if verbose:
-            print self.getName(), 'is finished.', self.nrunning.get(), \
-                  'tasks are running'
-        self.mutex.release()
-
-        self.sema.release()
+            with self.mutex:
+                self.nrunning.dec()
+                self.testcase.assert_(self.nrunning.get() >= 0)
+                if verbose:
+                    print '%s is finished. %d tasks are running' % (
+                        self.getName(), self.nrunning.get())
 
 class ThreadTests(unittest.TestCase):
 
@@ -218,6 +214,10 @@
         rc = subprocess.call([sys.executable, "-c", """if 1:
             import ctypes, sys, time, thread
 
+            # This lock is used as a simple event variable.
+            ready = thread.allocate_lock()
+            ready.acquire()
+
             # Module globals are cleared before __del__ is run
             # So we save the functions in class dict
             class C:
@@ -229,10 +229,11 @@
 
             def waitingThread():
                 x = C()
+                ready.release()
                 time.sleep(100)
 
             thread.start_new_thread(waitingThread, ())
-            time.sleep(1) # be sure the other thread is waiting
+            ready.acquire()  # Be sure the other thread is waiting.
             sys.exit(42)
             """])
         self.assertEqual(rc, 42)
@@ -242,9 +243,11 @@
         # threading.enumerate() after it has been join()ed.
         enum = threading.enumerate
         old_interval = sys.getcheckinterval()
-        sys.setcheckinterval(1)
         try:
-            for i in xrange(1, 1000):
+            for i in xrange(1, 100):
+                # Try a couple times at each thread-switching interval
+                # to get more interleavings.
+                sys.setcheckinterval(i // 5)
                 t = threading.Thread(target=lambda: None)
                 t.start()
                 t.join()