🔍 Go binary size SVG treemap

Make treemap breakdown of Go executable binary

$ go install github.com/nikolaydubina/go-binsize-treemap@latest
$ go tool nm -size <binary finename> | go-binsize-treemap > binsize.svg

Disclaimer

Should you be worried about executable binary size? In 2022, few seconds of cat videos or even a single image is tens of MBs. Transferring them over network is not a big deal either. So, probably, you should not worry too much about it. However, this tool can still be useful in couple of cases.

• You are studying compiler.
• You are investigating what 3rd party dependencies are getting included in binary.
• You are checking much data is getting embedded.
• You are estimating how much code is getting included by packages.
• You are researching which symbols included.
• You are doing cgo.
• You are doing treemap visualizations.

I build this in my spare time as another usecase for Go treemap tooling that I built before. Enjoy! Submit issues or PRs!

Examples

github.com/gohugoio/hugo

github.com/cockroachdb/cockroach

github.com/goccy/go-graphviz

github.com/zalando/skipper

Knowledge Base

What is go.itab?

This is interface related code. Refer to this article by Russ Cox.

What is runtime.pclntab? And why it is so big?

As investigated Cockroach team, it is Go runtime structure for traces (reference). Past discussions in GitHub thread on why it is big and what to do about it (well, nothing).

Known Issues and TODOs

• Size slightly mismatches actual binary size. Including unknown does not help.
• Better symbol names parsing for C++
• identify go:embed
• color by type + increasing luminance (sys; user; c++; go:embed; etc.)
• color by symbol type
• heat by ????

Related Work

• https://github.com/knz/go-binsize-viz — this was an inspiration for current tool. However, instead of Python and D3 and Javascript, this tool is using single stack purely in Go and has test coverage. Arguably, the downside it is not interactive.
• https://github.com/jondot/goweight — looks like it was working in the beginning, but as of 2022-01-22 it does not work anymore for me and there were reports dating back to 2020-01-23 for it to be not accurate.

Reference

• https://github.com/knz/go-binsize-viz
• https://github.com/jondot/goweight
• https://github.com/nikolaydubina/treemap
• https://github.com/nikolaydubina/go-cover-treemap
• https://github.com/golang/go/blob/master/src/cmd/nm/doc.go
• https://linux.die.net/man/1/c++filt
• https://github.com/goccy/go-graphviz
• https://research.swtch.com/interfaces

Appendix A: Strange Output / C++ / CGO

You many need to demungle symtab file first. Install c++flit. Then process symtab first. Note, c++ support is work in progress.

$ go tool nm -size <binary finename> | c++filt | go-binsize-treemap > binsize.svg

Appendix B: Large dimensions and lots of details

If you set dimensions very large you can see lots of details and navigate map.

4096x4096 is recommended

... but you can go much higher

Appendix C: Small dimensions and informative preview

You can generate small preview of project that fits for embedding in README for example.

1024x256 is recommended