py-spy 0.1.0

A Sampling Profiler for Python

py-spy is a fast sampling profiler for Python programs. py-spy lets you visualize what your Python program is doing without restarting the program or modifying the code in any way. py-spy is low overhead and won’t pause or slow your Python program down - meaning that it is safe to use in production.

To install:

pip install py-spy

py-spy supports Python versions 2.3+ and 3.3+ on Linux, OSX and Windows.

Usage

py-spy works from the command line, and takes either the PID of the program you want to sample from, or the command line of the python program you want to run:

py-spy --pid 12345
# OR
py-spy -- python myprogram.py

The default visualization is a top-like live view of your python program:

console viewer demo

There is also support for generating flame graphs from the running process:

py-spy --flame profile.svg --pid 12345
# OR
py-spy --flame profile.svg -- python myprogram.py

Which will generate a SVG file looking like:

flame graph

Credits

py-spy is heavily inspired by Julia Evans excellent work on rbspy. In particular the code to generate the flamegraphs is taken directly from rbspy, and this project use several crates (read-process-memory and proc-maps) that were spun off from rbspy.