You'd normally look at a more convenient visualisation of this data, usually in the form of a flame graph, which shows you aggregated figures for functions and

You'd normally look at a more convenient visualisation of this data, usually in the form of a flame graph, which shows you aggregated figures for functions and the actual call stacks. If you don't care much about %'s you could still learn a lot about how a program works (especially if you're not familiar with it) just by looking at the call stacks. The VS Code extension makes this quite easy to do since you can click on the interactive flame graph to hop directly to the source code and peek around. See for example https://p403n1x87.github.io/how-to-bust-python-performance-issues.html https://p403n1x87.github.io/how-to-bust-python-performance-i..., which en passant shows you how pytest works internally