Advanced Go Concurrency

f you’ve used Go for a while you’re probably aware of some of the basic Go concurrency primitives:

  • The go keyword for spawning goroutines
  • Channels, for communicating between goroutines
  • The context package for propagating cancellation
  • The sync and sync/atomic packages for lower-level primitives such as mutexes and atomic memory access

These language features and packages combine to provide a very rich set of tools for building concurrent applications. What you might not have discovered yet is a set of higher-level concurrency primitives available in the “extended standard library” available at We’ll be taking a look at these in this article.

Go memory ballast: How I learnt to stop worrying and love the heap

Go memory ballast: How I learned to stop worrying and love the heap

I’m a big fan of small code changes that can have large impact. This may seem like an obvious thing to state, but let me explain:

  1. These type of changes often involve diving into and understanding things one is not familiar with.
  2. Even with the most well factored code, there is a maintenance cost to each optimization you add, and it’s usually (although not always) pretty linear with the amount of lines of code you end up adding/changing.

We recently rolled out a small change that reduced the CPU utilization of our API frontend servers at Twitch by ~30% and reduced overall 99th percentile API latency during peak load by ~45%.

This blog post is about the change, the process of finding it and explaining how it works.

Building a BitTorrent client from the ground up in Go

BitTorrent is a protocol for downloading and distributing files across the Internet. In contrast with the traditional client/server relationship, in which downloaders connect to a central server (for example: watching a movie on Netflix, or loading the web page you’re reading now), participants in the BitTorrent network, called peers, download pieces of files from each other—this is what makes it a peer-to-peer protocol. We’ll investigate how this works, and build our own client that can find peers and exchange data between them.

diagram showing the difference between client/server (all clients connecting to one server) and peer-to-peer (peers connecting to each other) relationships

The protocol evolved organically over the past 20 years, and various people and organizations added extensions for features like encryption, private torrents, and new ways of finding peers. We’ll be implementing the original spec from 2001 to keep this a weekend-sized project.

Over 150 of the Best Machine Learning, NLP, and Python Tutorials

While machine learning has a rich history dating back to 1959, the field is evolving at an unprecedented rate. In a recent article, I discussed why the broader artificial intelligence field is booming and likely will for some time to come. Those interested in learning ML may find it daunting to get started.