Go Faster With Green Tea • The Applied Go Weekly Newsletter 2025-11-02
Your weekly source of Go news, tips, and projects
Go Faster With Green Tea
Hi ,
Go's garbage collector has gone through a remarkable journey. In Go 1.5, the Go team implemented a tri-color concurrent algorithm that reduced GC latency from 300-400ms to 30-40ms: an improvement of an order of magnitude. For Go 1.6, the team systematically eliminated O(heap) stop-the-world operations. Latency dropped to 4-5ms—the second order-of-magnitude improvement. Go 1.8 eliminated stop-the-world stack scanning at the end of a GC cycle. The result is the third order-of-magnitude improvement: a reduction to the sub-millisecond range.
From almost half a second to less than one millisecond: this is an impressive improvement, but the Go team didn't stop there. Go apps still spend a substantial part of their CPU time with collecting garbage. Multi-core architectures impose hurdles like non-uniform memory access and reduced bandwidth as memory is shared among an increasing number of CPU cores. A new interpretation of the mark-and-sweep algorithm attempts to address these hurdles: it's called Green Tea, and it's the eponymous hero of the Go Blog's latest article.
The Go garbage collector has seen spectacular efficiency improvements over time, but even the first version had an incredible superpower: It let developers focus on features instead of babysitting memory. What a huge time-saver!
–Christoph
Featured articles
The Green Tea Garbage Collector - The Go Programming Language
Take a seat, and have a big cup of good green tea. This is a long article. But totally worth the time! There's a lot to learn: about mark-sweep, graph floods, vector acceleration, and, most importantly, where the Green Tea algorithm got its name from.
Introduction to Gthulhu
Can you replace the Linux scheduler with a scheduler written in less than 300 lines of Go code? Apparently you can, because otherwise this article (and the project behind it) wouldn't exist.
I'm Independently Verifying Go's Reproducible Builds
"Trust me, I have verified the claims I'm making!" The Go toolchain is designed in a way that guarantees reproducible builds, but this guarantee only holds if a third party can verify it independently of Google. Andrew Ayer set out to do such an independent verification. As a contributor to Debian's Reproducible Builds project and author of Source Spotter, he is certainly qualified for the job.
Podcast corner
go podcast() | 065: We're in the 3rd age of SaaS
Dominic St-Pierre looks back at almost two decades of going through the adventures of entrepreneurship.
Quote of the Week: Sweeping predictions
LinkedIn needs a feature to filter out all AI hype written by people under 25.
I'm sorry, but if you graduated college three years ago you don't have enough software engineering experience to make sweeping predictions about how AI is going to destroy it.
I love Hillel Wayne's humorous posts. And I love this particular comment from Benjamin Jordan, too:
Hold on though because you only spent 1 year being 25 and here you are making sweeping generalizations about being 25, nice try
More articles, videos, talks
From 19 Hours to Under a Second: Building a Blazing-Fast TCP Scanner in Go | ServiceRadar
For network discovery purposes, ServiceRadar need to sweep 21k devices. Using a classic TCP connect() for this, the whole sweep takes more than 19 hours. By the time the sweep ends, the results are already outdated. The team threw in their knowledge of network and Go optimizations and reduced the sweep time to milliseconds. The ingredients: raw sockets, TPACKET_V3 rings, cBPF filtering, and a pinch of Go assembly.### Automating Golang Project Updates with Updatecli - Updatecli
Updatecli is, broadly speaking, a tool for specification-driven updates of files. This article focuses on how Updatecli can specifically support Go projects.### Go Context Logger
Steve Xuereb looks at a lesser-known slog functionality: context logging.### Discarding gRPC-Go: The Story Behind OTLP/gRPC Support in VictoriaTraces
VictoriaMetrics weren't quite happy with the protoc toolchain... and wrote their own gRPC stack with an HTTP/2 server and easyproto. ### Golang Concurrency, Channels, Goroutines, What I know about them? - YouTube
Why isn't concurrent programming more common, despite Go's powerful concurrency primitives? Parsa Eissazadeh explores the trade-offs of concurrency by examining concurrency concepts and the associated challenges.### Dependency Management in Database Design | DoltHub Blog
Everyone can write about import cycles, like this dude, but dealing with cyclic dependencies in a large project is another level. Dolthub's Nick Tobey shares two main insights in his article: Proper modularization is key to creating a maintainable project, and finding one's way around introducing a circular dependency can be trickier than it seems at a first glance. The devil's always in the details.
Projects
Tools and applications
Just a moment...
Need to take advantage of Go in your frontend JS code? Just type "use golang" and write Go code that automatically compiles to WebAssembly. Minor caveat: "Author here. The library was created as a joke. You need to take it with a grain of salt."#### GitHub - devasherr/gpad: Struct Padding Optimizer
If you do data-oriented design, this tool might be a useful addition to your toolbox.
Completely unrelated to Go
Programming With Less Than Nothing
I almost shared the fate of Dana in this hilarious article...
(via)### The job behind the job [of a high level IC] | Swizec Teller
"By having situational awareness and a long-term, you can do urgent things in a way that ladders you up to achieving long-term goals."### How to engineer luck - by George Mack - High Agency
Is luck just, well, luck, or can you develop something like a "luck skill"? George Mack believes in the latter, and he shares a baker's dozen tips for actively increasing your luck.
"Being a great luck engineer is turning yourself into a simple API that people can connect into."
Happy coding! ʕ◔ϖ◔ʔ
Questions or feedback? Drop me a line. I'd love to hear from you.
Best from Munich, Christoph
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