How does a threading.Thread yield the rest of its quantum in Python?
time.sleep(0) is sufficient to yield control -- no need to use a positive epsilon. Indeed, time.sleep(0) MEANS "yield to whatever other thread may be ready".
Read up on the Global Interpreter Lock (GIL).
For example: http://jessenoller.com/2009/02/01/python-threads-and-the-global-interpreter-lock/
Also: http://www.pyzine.com/Issue001/Section_Articles/article_ThreadingGlobalInterpreter.html
Do this in your code if you must do Busy Waiting (e.g. polling a device).
time.sleep( 0.0001 )This will yield to the thread scheduler.
Also, I collected some notes and references in http://homepage.mac.com/s_lott/iblog/architecture/C551260341/E20081031204203/index.html