An Introduction to Python Concurrency
Copyright (C) 2009, All Rights Reserved
Presented at USENIX Technical Conference, June 15, 2009
This tutorial is an overview of concurrent programming idioms in Python.
Requirements and Support Data Files
This tutorial requires the use of Python 2.6 or newer. No third party
modules are required. Examples have been tested on both Unix and Windows XP.
The following file contains some supporting data files that are used
by the various code samples. Download this to your machine to work with
the examples that appear in the tutorial.
This download also includes a PDF of the lecture slides.
Here are various code samples from the course. You can either cut and
paste these from the browser or simply work with them directly in the
"Concurrency" directory. The order in which files are listed follow the
Part 3 : Python Thread Programming
- countdown.py. A very simple thread (a first example).
- countdown2.py. Launching a function in a thread.
- race.py. Example of a race condition. Run multiple times to see different results.
Part 4 : Thread Synchronization Primitives
- lock_ex.py. An example of using a lock
to synchronize access to shared data.
- lock_with.py. An example of using
a lock with the Python 2.6 context-manager feature.
- rlock_ex.py. An example of code-based locking using
a reentrant lock.
- sema_signal.py. An example of using a
semaphore for signaling between threads.
- event_barrier.py. Using an
event to implement a synchronization barrier.
- event_notify.py. Using an
event and semaphore to implement a kind of notification mechanism.
- cond.py. An example of setting up
a producer-consumer problem with a condition variable.
Part 5 : Threads and Queues
- pc_queue.py. A producer-consumer problem
using threads and queues.
Part 6 : The Problem with Threads
- perf.py. A program that illustrates some
performance problems with threads.
Part 9 : Processes and Messages
- channel.py. An example of setting up a
message channel between processes using the subprocess module.
Part 10 : Multiprocessing
- countdownp.py. A very example of
launching a process.
- perfmp.py. A simple performance test of
CPU-bound processes. Compare to the thread example earlier.
- pipemp.py. An example of a multiprocessing
producer/consumer with a pipe.
- queuemp.py. Using multiprocessing queues.
- poolmp.py. An example of using a multiprocessing
Part 11 : Alternatives to Threads and Processes
- generator.py. A very simple example of
using generators to implement a form of cooperative multitasking.