First of all this isnt meant to be accurate or very reliable, even flawed, I just want to see some numbers, because in pymuxs README, it mentions about the performance, but not actual numbers:

Tmux is written in C, which is obviously faster than Python. This is noticeable when applications generate a lot of output. Where tmux is able to give fast real-time output for, for instance find / or yes, pymux will process the output slightly slower, and in this case render the output only a few times per second to the terminal. Usually, this should not be an issue. If it is, Pypy should provide a significant speedup.

1   Method

I use my own test script,, which is written in Bash. I thought about using find or yes as mentioned in the README, but I am too lazy to write a script for the tests, I used what I already have in hand.

Since pymux is written in Python, so I tested with two implementations, the official CPython and PyPy (RPython to C). They will all run within the environment virtualenv creates, and using pip to install pymux 0.5 and Pyte 0.4.10, and along with their dependencies.

The test script is run with reset && ./ in urxvtc with font xft:Envy Code R:style=Regular:size=20:antialias in dwm with virtually full-screen of 1680x1050, dwm topbar is hidden, and the window size is 1669x1027 and geometry is 111x33.

Both tmux and pymux are run without configuration files.

2   Used versions

name version note
urxvt 9.21 x11-terms/rxvt-unicode-9.21 2014-09-06 git-00559f9
tmux 1.8 app-misc/tmux-1.8
Python 2.7.10 dev-lang/python-2.7.10-r1
Python 3.4.3 dev-lang/python-3.4
PyPy 4.0.1 dev-python/pypy-bin-4.0.1
PyPy32 2.4.0 dev-python/pypy3-bin-2.4.0-r1
virtualenv 12.0.5 dev-python/virtualenv-12.0.5
Pymux 0.5  
six 1.10.0  
prompt-toolkit 0.57  
Pyte1 0.4.10  
docopt 0.6.2  
Pygments 2.0.2 from prompt-toolkit
wcwidth 0.1.6 from prompt-toolkit
[1]The latest Pyte 0.5.x (2016-01-11) doesnt work with pymux 0.5.
[2]PyPy3, there is a bug and cant be worked with virtualenv, the latest 2.4.0 (2014-10-09) doesnt include the fix (2015-02-06). The test is run without virtualenv created environment.

3   Result

From the fastest to slowest by the elapsed time:

test with version lines3 elapsed fps cps
urxvtc4 9.21 33 000.497 200.879 735,822
tmux 1.8 32 001.786 055.962 198,779
Python 2.7.105 31 028.237 003.541 012,185
PyPy 4.0.1 31 057.751 001.731 005,958
PyPy 2.4.0 31 070.458 001.419 004,883
Python 3.4.36 31 128.130 000.780 002,685
[3]Because of titlebar and/or status bar, there will be different in lines.
[4]urxvt is run without anything but the script, this is just for reference.
[5]Python 2.7.10 isnt working properly. From my eyes, I can not see some frames, it goes like 1, 4, 8, 2, 5, and so on. Some frames doesnt not seem displayed.
[6]All Python versions but PyPy3 are run within virtualenv created environments.

4   Conclusion

Although there is terminal lines differences up to 2 lines, but since results vary significantly, I ignored the lines without normalizing those numbers.

By numbers, Python 2 seems to win, but as the note above, its flawed. Some frames I didnt see. However, that doesnt mean those frames are dropped by pymux. They could somehow be buffered and flushed out with other frames, or some other explanations.

The only comparison can be done is between tmux and pymux (Python 3/PyPy/PyPy3). By the elapsed times:

  • Pymux (Python 3) is 81.85% slower than pymux (PyPy3) and 7,074% slower than tmux.
  • Pymux (PyPy3) is 3,845% slower than tmux and 22% slower slower than pymux (PyPy).

Of course, its a bit of extreme since the test script prints out the entire frame of characters at once, if I recall correctly. In real world case, most of program doesnt do full terminal size updates. Such as find and yes are outputting line by line, and they wont be full width every line.

The numbers, either 7,074% and 3,845%, are looking horrible, but the actual user experience with daily programs might not reflect those numbers.