Question

In Python for *nix, does time.sleep() block the thread or the process?

Answer 1

It blocks the thread. If you look in Modules/timemodule.c in the Python source, you’ll see that in the call to floatsleep(), the substantive part of the sleep operation is wrapped in a Py_BEGIN_ALLOW_THREADS and Py_END_ALLOW_THREADS block, allowing other threads to continue to execute while the current one sleeps. You can also test this with a simple python program:

import time from threading import Thread  class worker(Thread):     def run(self):         for x in xrange(0,11):             print x             time.sleep(1)  class waiter(Thread):     def run(self):         for x in xrange(100,103):             print x             time.sleep(5)  def run():     worker().start()     waiter().start() 

Which will print:

>>> thread_test.run() 0 100 >>> 1 2 3 4 5 101 6 7 8 9 10 102