<s>[INST] time.sleep -- sleeps thread or process? In Python for the *nix, does time.sleep() block the thread or the process?
 [/INST] 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

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