Python bug

gistfile1.py

import subprocess
import threading
import sys

the_cvar = threading.Condition(threading.RLock())
turn = 0
NTHREADS = 20
WINDOW = 1
ITERS = 100

class Worker(object):
    def __init__(self, id):
        self.id = id

    def fidget(self):
        with the_cvar:
            the_cvar.notifyAll()

    def say(self, x):
        for c in x:
            sys.stdout.write(c)
            self.fidget()
        sys.stdout.write('\n')
        sys.stdout.flush()
        self.fidget()

    def work(self):
        global turn
        for i in range(ITERS):
            self.say('%sthread %s iteration %s\n' % (' ' * self.id, self.id, i))

            while True:
                with the_cvar:
                    if (self.id - turn) % NTHREADS <= WINDOW:
                        turn = (turn + 1) % NTHREADS
                        the_cvar.notifyAll()
                        break
                    # self.say('%sthread %s sleeping' % (' ' * self.id, self.id))
                    the_cvar.wait()

        self.say("thread %s done" % (self.id,))

def worker(id):
    Worker(id).work()

threads = []
for i in range(NTHREADS-1):
    print 'starting thread %d' % (i+1)
    t = threading.Thread(target=worker, args=(i+1,))
    threads.append(t)
    t.start()

print 'starting thread 0'
worker(0)
for t in threads:
    t.join()