ChimiChanga
4 HN recommenders · recommended in 8 months, 2024–2026
46:40 · 416K views · Jul 13, 2024
Andrew Kelley, creator of Zig, presents practical data-oriented design techniques for shrinking memory footprint and making programs cache friendly. He ends with a case study of how these ideas sped up the Zig compiler.
HN cites it as one of the best talks on data-oriented design, applying struct-of-arrays and compact data layouts to a real compiler.
10 comments from Hacker News
A good introduction to SoA (for anyone curious) are the two most famous Data-Oriented Design talks by Mike Acton (game engine dev) [1] and Andrew Kelley (Zig lead dev) [2] respectively. I read a book book about DoD [3] really which confused me at first with all its talk about database table design (in a book about a high-performance C++ game engine?), but when it finally clicked it was amazing. The point is that you want to think hard about your access patterns and what could constitute good "primary keys", then model it accordingly. SoA ends up being useful a lot of the time, because having your data in homogeneous arrays/vectors is great for cache locality and branch elimination. Even without SIMD you can get huge speedups from that, but that's also where your compiler (or you as a programmer) can get incredible SIMD gains. SoA is not a silver bullet as it may not align well with your access patterns, but it can great to add to your toolkit. --- Mike Acton: Data-Oriented Design and C++ : [LINK] Andrew Kelley: A Practical Guide to Applying Data Oriented Design : this video Richard Fabian: Data-Oriented Design : [LINK]
I recently spent a week or so creating a library for my project. There's not a lot of code, but it was hard to reason about the data model, what I wanted the API to look like, and what I wanted actually rendered on the other side. I was proud after getting it working, but when I had to run dozens of files through it, it was horribly slow. I don't tend to write a lot of hot code, so I was excited by the fact I had to profile it and make it efficient. I decided that I should rewrite the system, as my mental model had improved and the code was doing a lot more than it should be doing for no reason. I've spent the last few days redesigning it according to Data-Oriented Design. I'm trying to get the wall-clock time down by more than an order of magnitude. I'm not sure how it's going to turn out, wish me luck :) Since I mentioned DoD, these three links will probably come up in conversation: Mike Acton's famous performance talk: [LINK] DoD in the Zig compiler: this video The DoD book: [LINK]
That talk is great, but I remember some discussion later about Go actually NOT using this technique because of goroutine scheduling overhead and/or inefficient memory allocation patterns? The best discussion I could find is [1]. Another great talk about making efficient lexers and parsers is Andrew Kelley's "Practical Data Oriented Design" [2]. Summary: "it explains various strategies one can use to reduce memory footprint of programs while also making the program cache friendly which increase throughput". -- 1: [LINK] 2: this video
This reminds of an amazing talk by Mike Acton on Data oriented design: [LINK] And there is a related talk by Andrew Kelley implementing these ideas on Zig toolchain: this video
SoA is nothing new. Not sure why it needs to be even discussed... Anyway, here's few videos of interest: [LINK] this video Odin also supports SoA natively [LINK]