Memory management in Go or To GC or not to GC #
Hybrid Meetup #49 took place 2025-03-25 19:00 at CHECK24 Leipzig Office and we had a great introduction to memory management with Go by Fabian.
Slides and quiz can be found at mentimeter.com.
We also have an archive of that page.
Some rules to program by:
- Stack allocation are better then heap allocation
- Number of heap allocations are more important than size of heap allocations
- Reduce the number of pointers in heap to reduce mark phase costs
- Be aware of the memory layout of you structs
- Make sure that every goroutine returns at some point (to avoid leaks)
- Use pprof to determine problems in you program
There is a great GC guide at: doc/gc-guide, and a few SO questions tagged with Go and GC
A tool for visualizing is structlayout.
$ go install honnef.co/go/tools/cmd/structlayout@latest
$ go install github.com/ajstarks/svgo/structlayout-svg@latest
You can then generate struct layout diagrams.
$ structlayout -json runtime slice | structlayout-svg -t "runtime.slice" > /tmp/struct.svg
$ structlayout -json bufio Reader | structlayout-svg -t "bufio.Reader" > /tmp/struct.svg
$ structlayout -json net/http Response | structlayout-svg -t "net/http.Response" > /tmp/struct.svg
Some more memory related types:
- sync.Pool
- memory arenas (experimental, but likely be declined)
Thanks again Fabian for the great presentation!
VPN and any of those problems #
Run your own VPN mesh with headscale (or ionscale) as the tailscale control server.
Slides: LGO49-RYOVPN.pdf.
Where does the name tailscale come from? From the 2013 Google paper The tail at scale.
The long tail of products are never going to be that big [ie. as a hyperscaler] — almost everybody building almost everything doesn’t have any of those problems. – Avery Pennarun at 45:56…
PS. Find great gifs for your next presentation at gifcities.org.
Misc #
- LLM use case snapshot: documentation navigation (using an LLM feels like using SO in the 2010s), writing 5-10 lines functions, writing narrow types, e.g. a helper to fill a type with random values; build tool scripts adjustments; emacs has gptel (example RAGmacs), a workflow that takes a URL and summarizes the content directly in emacs is easy; also great tool use in elisp or beyond; LLM as brainstorming/research tool
- Waterfall style systems building seems to be hard to follow these days (a grand plan seldom survives contact with reality), preferring throwaway code over design docs may be a better way, as designs can be discovered with code while throwing away code is part of building a theory around the requirements and forces surrounding software
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