added barrier test (by Tim Peters)

Lib/test/test_thread.py

@@ -7,13 +7,18 @@ import thread
 import time
 
 mutex = thread.allocate_lock()
+whmutex = thread.allocate_lock() # for calls to whrandom
 running = 0
 done = thread.allocate_lock()
 done.acquire()
 
+numtasks = 10
+
 def task(ident):
 	global running
-	delay = whrandom.random() * 10
+	whmutex.acquire()
+	delay = whrandom.random() * numtasks
+	whmutex.release()
 	print 'task', ident, 'will run for', delay, 'sec'
 	time.sleep(delay)
 	print 'task', ident, 'done'
@@ -33,9 +38,69 @@ def newtask():
 	running = running + 1
 	mutex.release()
 
-for i in range(10):
+for i in range(numtasks):
 	newtask()
 
 print 'waiting for all tasks to complete'
 done.acquire()
 print 'all tasks done'
+
+class barrier:
+	def __init__(self, n):
+		self.n = n
+		self.waiting = 0
+		self.checkin  = thread.allocate_lock()
+		self.checkout = thread.allocate_lock()
+		self.checkout.acquire()
+
+	def enter(self):
+		checkin, checkout = self.checkin, self.checkout
+
+		checkin.acquire()
+		self.waiting = self.waiting + 1
+		if self.waiting == self.n:
+			self.waiting = self.n - 1
+			checkout.release()
+			return
+		checkin.release()
+
+		checkout.acquire()
+		self.waiting = self.waiting - 1
+		if self.waiting == 0:
+			checkin.release()
+			return
+		checkout.release()
+
+numtrips = 3
+def task2(ident):
+	global running
+	for i in range(numtrips):
+		if ident == 0:
+			# give it a good chance to enter the next
+			# barrier before the others are all out
+			# of the current one
+			delay = 0.001
+		else:
+			whmutex.acquire()
+			delay = whrandom.random() * numtasks
+			whmutex.release()
+		print 'task', ident, 'will run for', delay, 'sec'
+		time.sleep(delay)
+		print 'task', ident, 'entering barrier', i
+		bar.enter()
+		print 'task', ident, 'leaving barrier', i
+	mutex.acquire()
+	running = running - 1
+	if running == 0:
+		done.release()
+	mutex.release()
+
+print '\n*** Barrier Test ***'
+if done.acquire(0):
+	raise ValueError, "'done' should have remained acquired"
+bar = barrier(numtasks)
+running = numtasks
+for i in range(numtasks):
+	thread.start_new_thread(task2, (i,))
+done.acquire()
+print 'all tasks done'