time.sleep — sleeps thread or process?

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

Answers:

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Method 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

Method 2

It will just sleep the thread except in the case where your application has only a single thread, in which case it will sleep the thread and effectively the process as well.

The python documentation on sleep() doesn’t specify this however, so I can certainly understand the confusion!

Method 3

Just the thread.

Method 4

The thread will block, but the process is still alive.

In a single threaded application, this means everything is blocked while you sleep. In a multithreaded application, only the thread you explicitly ‘sleep’ will block and the other threads still run within the process.

Method 5

Only the thread unless your process has a single thread.

Method 6

Process is not runnable by itself. In regard to execution, process is just a container for threads. Meaning you can’t pause the process at all. It is simply not applicable to process.

Method 7

it blocks a thread if it is executed in the same thread not if it is executed from the main code

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0