Nuitka: nuitka binaries slow performance with Python3 in-place string add

Nuitka version:

0.6.0rc4
Python: 3.6.6 (default, Sep 12 2018, 18:26:19) 
Executable: /usr/bin/python3
OS: Linux
Arch: x86_64

Installed via: apt

Greetings,

Really love this project. Thanks for all your hard work on it. My nuitka binaries generally perform really well, even for complex projects. The one exception is when I implement code that generates a large volume of random numbers. The code below is much slower in a nuitka build when compared to running it in the python3 interpreter:

chars = []
for i in range(256):
   chars += [chr(i)]
wrapper = ""
for i in range(10000000):
   wrapper += random.choice(chars)

About this issue

Original URL
State: closed
Created 6 years ago
Comments: 21 (12 by maintainers)

Most upvoted comments

Thank you again! I can see how creating strings (which are immutable in python) would be a waste. I re-factored the code to use lists rather than strings, with a final .join() at the end, and it is indeed much faster in nuitka. It now looks like this:

n = 10000000

chars = []
for i in range(256):
   chars += [chr(i)]

wrapper = ['*'] * n
for i in range(n):
   wrapper[i] = random.choice(chars)

s = "".join(wrapper)

geozeke on Sep 25, 2018