Optimize! Optimize! Optimize! • The Applied Go Weekly Newsletter 2024-01-28

Your weekly source of Go news, tips, and projects

If your working time passes slowly like a turtle trudging through peanut butter, this might be because you have to wait for slow apps to respond. Time for some optimizations! To get you started, the first two featured articles are all about optimizing for performance.

Optimizing Go code for the CPU Cache - YouTube

Every CPU core has its own local cache. For multithreaded applications, those local caches can become a bottleneck. If two threads running on different cores share data, the cores must transfer the data from one local cache to the other.

Goroutines are scheduled onto system threads dynamically and therefore cannot be pinned to specific CPU cores. In this video, William Moran explores the effects of CPU caching on the performance of Go applications.

Optimizing Go code for the CPU Cache - YouTube

From slow to SIMD: A Go optimization story

Optimization typically happens in multiple rounds. Camden Cheek describes Sourcegraph's journey in optimizing a critical dot product function, from quantizing vectors to 8-bit integers to using handwritten SIMD assembly in Go, resulting in dramatic performance improvements.

From slow to SIMD: A Go optimization story

Share your feedback about developing with Go - The Go Programming Language

Every six months, the Go Developer Survey seeks feedback from Go developers. The survey for H1 2024 is now open. Share your feedback until Feb 11th and help make Go even better!

Share your feedback about developing with Go - The Go Programming Language

Podcast corner

Backend Banter

Matt Holt, creator of the Caddy webserver, chats with Lane Wagner about the origins and unique features of Caddy, why the Caddyfile has no extension, and lots of other topics around Caddy and Matt's journey in Go programming.

Backend Banter | #037 - Caddy Chronicles with Matt Holt

Cup o' Go

Did Jonathan Hall's cat roll over his keyboard, or what's about the title of the latest Cup o' Go episode? It probably has to do with the recently declined proposal to have benchstat optionally support ASCII-only output. Also discussed: The new range syntax, debugging Go compiler performance, and more.

Cup o' Go | 📐 ⓦide rąnge οf tøpics wíth Yarɗen Laifėnfeld as gµest hoʂt

Go Time

Episode #300 is out! The panelists look back on 8 years of Go Time and share their favorite episodes.

300 multiple choices (Go Time #300) |> Changelog

Ardan Labs Podcast

Jesús Espino talks about his work as Senior Staff Engineer at Mattermost, his transitioning to Go, and how knowledge about Go internals helps solving programming problems.

Mattermost, Go, and Tech Talk with Jesús Espino

go podcast()

In this episode, Dominic St-Pierre suggests that companies should try harder to improve their interview and onboarding processes.

go podcast() | 026: We can do better with interviews and onboarding

Stray Pointers

Ben Hoyt talks to Jim Lawless about his experience with various languages, including Go.

Stray Pointers: Discussing Programming Languages with Ben Hoyt

Go tip of the week: Value receivers and nil

Imagine a struct with two methods; one has a pointer receiver and the other has a value receiver.

package main

type S struct {
    N int
}

func (s *S) PointerRcv() {
}

func (s S) ValueRcv() {
}

What happens if the receiver is nil?

func main() {
    var s *S // s is nil
    s.PointerRcv()
    s.ValueRcv()
}

Variable s assumes the zero value of *S, which is nil. None of the two method accesses the receiver, so both method calls should go through without issues.

However, if you run this code, the call to s.ValueRcv() panics!

What happens here?

Consider that methods are simply functions with some syntactic sugar. A method func (s S) f() is semantically identical to the function func f(s S). The method receiver becomes the first argument of the function.

Thus, the above code can be written without methods as follows:

package main

type S struct {
    N int
}

func PointerFunc(s *S) {
}

func ValueFunc(s S) {
}

func main() {
    var s *S // s is nil

    PointerFunc(s)
    ValueFunc(*s)
}

Now it should be easy to see why ValueFunc() panics. The pointer s must be dereferenced when passing it to ValueFunc(). Dereferencing a nil pointer is not possible and results in a panic.

For the method func (s *S)PointerRcv(), the receiver (or the function parameter in the second example) does not need to get dereferenced. Hence no panic occurs.

So if you have a type with pointer and value receivers, take care to not call any methods on a nil value of that type.

Overheard on LinkedIn: I have a joke about UDP

I have a joke about UDP and I don't care if you get it.

– Shawn Plowman

I tried to come up with an IPv4 joke, but the good ones were all already exhausted.

– Nick B.

I wanted to share a joke about IPv6, but there are too many to choose from.

– Dinesh Gurnani

(Source: LinkedIn)

More articles, videos, talks

Scaling GraphQL Subscriptions in Go with Epoll and Event Driven Architecture - WunderGraph

While this post is primarily about a new feature of Wundergraph's product, it also shares valuable insights into using pprof for profiling goroutines and heap allocations.

Write Integration Tests For Mongo With Golang - Hasan Ocak Tech Blog

What's so special about MongoDB integration tests? Well, MongoDB, that is. Hasan Ocak shows how it's done.

Go directives

Are compiler directives the new hot sh*t in code optimization? Victor Conner shares his experiences using the //go:nosplit directive during the Advent of Code for a measurable speedup.

Omitting dev dependencies in Go binaries | Redowan's Reflections

If you want to track binary dependencies (a.k.a. development tools) in a Go project, a tools.go file guarded by a build tag does the trick.

Stop stamping commit info in Go projects | Wilson Husin

If you use flags to stamp arbitrary version info into Go binaries, consider adding the exact commit revision using debug.ReadBuildInfo(), for higher accuracy and better build reproducibility.

In Go, I'm going to avoid using 'any' as an actual type

The empty interface, or interface{} never received much love. Now it's increasingly replaced by the alias any, which is easier on the eyes (but still has the same connotation of poking holes in type safety). Chris Siebenmann is not happy with any as a general replacement for interface{}.

Projects

Libraries

Libraries that have been announced this week

GitHub - ionoscloudsdk/comptplus: cobra-prompt with flag completions

comptplus enhances Cobra's cobra-prompt library with flag completions and persistence, customizable flag reset behavior, and pre- and post-execution hooks.

GitHub - maniartech/signals: A robust, dependency-free go library that provides simple, thin, and user-friendly pub-sub kind of in-process event system for your Go applications.

Signals is for single processes what NATS or RabbitMQ are for distributed applications. Signals provides a process-internal event system if plain channels are too simple and other approaches are too complex.

GitHub - hossein1376/grape: Modern, zero-dependency HTTP library for Go

A convenience layer on top of the std library for building HTTP servers with slog logging and the upcoming, improved HTTP router (in Go v1.22).

Tools and applications

GitHub - rico-vz/SleepSageCLI: Optimal sleep calculator directly from your terminal ✨

Maybe not that useful for real life (as it doesn't track your sleep, but OTOH, that's the last thing I want my terminal to do!), but surely a nice showcase of writing interactive CLI apps with charmbracelet/huh and charmbracelet/log.

GitHub - rednafi/link-patrol: Detect dead links in markdown files

Ooh, that's the tool I need! This newsletter, as well as my blogs, start their life as Markdown files, and while it's hard to change a link in an already sent email, blog articles should at least be kept up-to-date with active links.

Pong Multiplayer

A 3D Multiplayer Pong! You can play against an AI if no human players are available. You wouldn't guess that this is a "My First Go Project" kind of application.

Completely unrelated to Go

TIL: In my shell, I can bind CTRL-r to fzf and get an interactive, crazy fast fuzzy search through my command history while typing.

Which command did you run 1731 days ago? - by Thorsten Ball

•—•—•

One reason for loving Go is its support for writing clear code. But there is more to achieving and maintaining clarity in software.

The most important goal in designing software is understandability | nicole@web

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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