The Problem
My program is slow, and I don’t know what it’s doing!
Goal:
Don’t do this, and it will be fast!
How?
Understand where time is spend during execution
Profiling
- Gather data
- short runs: deterministic:
cProfile
- longer runs: statistical: Austin
- Analyze data
- flame graph/icicles, sunburst: SnakeViz or Speedscope
- call graph
Gathering data: cProfile
python -m cProfile -o cprofile.dat <PROGRAM>.py
- Build-in tool
- Deterministic
- No multiprocessing/threading support
Gathering data: Austin
sudo apt install austin
austin python <PROGRAM>.py
- Statistical profiler
- Supports child processes
- Supports attaching to running processes
Visualization: SnakeViz
Works with profiles generated by cProfile.
pip install snakeviz
python -m cProfile -o cprofile.dat <PROGRAM>.py
snakeviz cprofile.dat
Visualization: Callgraph
gprof2dot
$ sudo apt-get install graphviz
$ git clone https://github.com/jrfonseca/gprof2dot
$ ln -s "$PWD"/gprof2dot/gprof2dot.py ~/bin
$ cd $PROJECT_DIR
$ gprof2dot.py -f pstats cprofile.dat | dot -Tsvg -o callgraph.svg
(pycallgraph is a python specific alternative)
