YouTube video by Sebastian Schöner

My current sidequest is to improve the codegen for Unity games (and the editor) running on Mono. This post is a continuation of last week’s post about this journey. To LLVM or not to LLVM? The first d...

My current sidequest is to improve the codegen for Unity games (and the editor) running on Mono. This post and the next two are about this process and what I learned. In this post, I am going to give ...

tl;dr: I am tinkering with improved codegen for Mono to get better performance in the Unity Editor and in Unity games that ship with Mono as their runtime. Not done yet, but please do get in touch if ...

I am currently on a side quest to write some Zig code, or more specifically: take some C++ code that is written in a I-can’t-believe-it’s-not-C style and turn it into Zig. This entire adventure starte...

My friend Stefan Reinalter is asking: I find this extremely worrying, with many of people I respect saying things like “I no longer write code” or “let LLMs do it”. Why did you start programming? Was ...

Let’s talk about reader-writer locks. Reader-writer locks are what you employ when you know that multiple readers can safely access a resource concurrently, but once there is a single writer that writ...

Embark on a journey about why you should sometimes trust your OS more than yourself.

This post is a continuation of my last post about programming with AI agents. I wanted to specifically talk about one property of Claude Code: The constant “Yes, of course!” and “That’s a brilliant id...

There are less than 2 weeks left in 2025 and this means it is time to look back at the last year. In last year’s review I ended on this note: For the next year, I hope to spend more timing painting in...

I want to write a few words about what sorts of games benefit from my build postprocessor for Unity il2cpp builds, cpp2better. It’s not the case that every game unconditionally benefits from it to the...

A friend recently joked that all my blog posts are to some level just trauma processing. He is not entirely wrong. Today’s trauma is “why does it take 12s to recompile C# when nothing has changed?” I ...

It’s been a while since I last talked about cpp2better. Time for an official “here it is” post. What is cpp2better? cpp2better is a tool that hooks into your build pipeline for Unity to achieve better...

I have been unfortunate enough to embark on a journey of C++ cross-compilation, by choice nonetheless. In my case, I use clang to compile on a Linux machine to get binaries for a Windows machine. This...

At the risk of alienating almost everyone reading this blog, I wanted to report some first hand experience of interacting with AI for programming. I specifically want to talk about how I accidentally ...

In the past, I used to work in a codebase that had a lot of // @TODO: comments in it. Those TODOs would rank from obvious, small improvements to calls for features that would require an entire rewrite...

Over the years I have come to appreciate “unreasonable” coworkers. What a weird sentence to write, right? When it comes to programming, you are usually fairly well advised to be “reasonable.” For exam...

I had two interactions recently that surprised me in light of how I think about this blog. In the first interaction, someone referred to me as a “performance expert.” Thank you, that’s very kind of yo...

I recently found myself wondering whether it is faster to compile C than C++. On some level, the answer to this is an obvious “yes”: You can’t accidentally summon cthulhu SFINAE-thulhu in your C code,...

For reasons, I have found myself writing a vector math library. Like Aras some time ago I’ve found an unpleasant surprise when looking at the debug performance of some vector types. There is no point ...

At some point when optimizing software, you are left with a soup of pointers that you just have to dereference, even though you know that you are going to suffer a cache miss for every single read. Co...

Last time, we looked at callbacks you can directly embed into your binaries on Windows that are then called for every thread on start/end. The runtime is using this to initialize thread-locals that re...

I recently needed to run a callback on thread shutdown and creation, on Windows. For exiting, you can apparently use FlsAlloc (MSDN), which is a part of the Fiber API. I’ve tried that, it works. But t...

Quite often, I see this: Forget it, I’m stupid, this is all wrong. or Sorry, I broke it, it was a stupid and unnecessary mistake. While some mistakes are actually unnecessary and completely avoidable,...

I recently had to understand the details of what happens when on Windows you have a global variable in a DLL and try to use it from another. I did not find this spelled-out anywhere, so let’s change t...

Recently I got a message from someone that ran into a performance problem with a tool I wrote 15 years ago. On shutdown, the program would completely grind the entire machine to a halt for 3 minutes. ...

I have been grappling with a really silly C++ problem for a long time: I don’t like member functions, but I need to write member functions to get a decent programming UX. Member functions give me two ...

I have in the past had this very romantic belief that when you pass a struct by value the compiler will lovingly select the right combination of registers to carefully craft the perfect packing of you...

This is a post about Unity’s ECS (as of Unity 6) and how it handles dependencies between jobs. The other day a friend asked: “Why are the different methods of scheduling work in Unity’s ECS so inconsi...

I have already introduced my latest project cpp2better in a previous post. I have made good progress and wanted to share some results. I have had the chance to test my tool on more projects now and ca...

deplinenoise has 39 repositories available. Follow their code on GitHub.

After the last post, you might think that I have spent most of my time lately with IL2CPP. That, however, is untrue: I have actually mostly been looking at GPU hangs. I would by no means call myself a...

IL2CPP is Unity’s AOT solution for C#, which takes compiled C# in the form of IL-code and turns it into C++ code, which can then be compiled using regular native toolchains. I have looked at a lot of ...

This blog post is 20 paragraphs exposition and 2 paragraphs punchline. It is a follow-up to my previous post on vectorization. I mentioned there that Unity’s math package implements bool4 like this: s...

In a recent discussion around auto-vectorization someone suggested: “What if users could tell the compiler that they expect a loop to be vectorized?” We are in luck, that experiment has already been c...

There is this general assumption that engines get better just by having the engine maker also use the engine to make games. I want to add some thoughts to that. At Unity, one of the main arguments aga...

I have been waiting for Visual Studio 2022 to unfreeze for the last 30min, and now you get to read about it. Curiously, this freeze has appeared more or less spontaneously after I opened a solution, t...

Someone asked the other day what a reasonable performance target is for a general purpose engine. This is an interesting question, so let’s discuss it a bit. When you build some subsystem in the conte...

Last time, I wrote about data and decision making, and some frustrations when people pretend like “data” is always the solution. Now let’s look at a place where data very often is (part of) the answer...

I recently looked into setting up a Unity cache server (“Accelerator”). It is quickly becoming clear that the accelerator is not, in fact, accelerating Unity. Here is a list of shortcomings: Some of t...

Data! Everybody loves Data! Let’s use data to make all our decisions. The worst leaders that I have seen are leaders that refuse to actively set direction. They say things like “we should be data-driv...

I recently had someone reach out to me and ask this question: I see a lot of people that were at Unity, left, went to Epic, and a year later they are independent. Is Epic really such a terrible place ...