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C implementation of Python 2 threading syncronization primitives

Project description

cthreading implements Python 2 Lock, RLock, and Condition in C. Like pthreading <>, without the undefined behavior or the overhead of pure Python and ctypes.

Build status: Travis-CI Build Status


cthreading eliminates the overhead of threading.RLock and threading.Condition which are implemented in pure Python in Python 2. In particular, threading.Condition is implemented using polling. In Python 3 threading.Condition is implemented without polling; cthreading implements similar design in C.

$ time python -m cthreading
real    0m2.664s
user    0m2.965s
sys     0m0.808s

$ time python3
real    0m9.664s
user    0m8.949s
sys     0m1.812s

$ time python
real    0m14.914s
user    0m16.986s
sys     0m12.690s

$ time python -m pthreading
real    0m20.169s
user    0m23.062s
sys     0m17.022s

Your application is unlikely to have similar workload; do not expect this improvement.

For more info see


Import cthreading before any other module and monkeypatch the thread and threading modules. From this point, threading.Lock, threading.RLock, and threading.Condition are using cthreading.

import cthreading


Tested on:

  • Fedora 22 / Python 2.7.10
  • RHEL 7.1 / Python 2.7.5
  • RHEL 6.7 / Python-2.6.6
  • Ubuntu 14.04 Server / Python 2.7.6
  • Ubuntu 12.04 Server / Python 2.7.3 (python regression tests not available)
  • Ubuntu 12.04 / Python 2.6.9 (Travis container)
  • Ubuntu 12.04 / Python 2.7.9 (Travis container)


For rpm based distributions:

yum install python-devel python-test

For deb based distributions:

apt-get install python-dev libpython2.7-testsuite

Installing Python packages:

pip install pytest pytest-timeout yappi==0.93

Building and running the quick tests:


Before submitting patches, run the Python regression tests suite:

make regrtest

Check the Makefile for more info.

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