flame_graphs.md

Flame Graphs

What is a flame graph? Simply speaking, a human-readable insight into what kept CPU busy (and it resembles fire 🔥).

It has intelligent zoom that lets you narrow down the range to a particular function from the flame and go back quickly at will.

It also supports hovering while still being a regular, valid *.svg file.

You can view an example of Polygon benchmark flame graph in assets/torch.svg.

NOTE: you must display the image file directly to use cool features described above.

Generating flame graph

Install go-torch and FlameGraph if you haven't done it before.

go get github.com/uber/go-torch

# In any directory, $HOME for example.
git clone https://github.com/brendangregg/FlameGraph

# You might want to add this to your .bashrc or other equivalent.
# NOTE: replace the path with the one you chose for your FlameGraph installation.
export PATH=$PATH:$HOME/FlameGraph

From now on, every time you want to generate a flame graph, simply run the commands below:

You can replace Polygon with any function name from *_test.go file, with name starting with Benchmark*, stripping the prefix.

For example, func BenchmarkPolygon(...) became Polygon.

go test -run NONE -bench Polygon -cpuprofile prof.cpu
go tool pprof triangolatte.test prof.cpu
go-torch triangolatte.test prof.cpu

Now you can open newly generated torch.svg in your web browser.