# 1BRC in Zig! My program ran in 1.12 seconds > Source: > Published: 2026-10-25 14:59:29+00:00 # Hi Zig community! I recently did the one billion challenge (1BRC) with Zig and wanted to share my blog post. I’ve been using Zig in all my recent projects and I am amazed at how quickly I have begun to feel productive. I think it’s a testament to the simplicity and focus on code readability. Check out my post here!: [One Billion Row Challenge](https://mattymo.dev/posts/one-billion-row-challenge) Also, I am super open to feedback. Thanks for reading! 9 Likes Would the recent talk about using SIMD for the Zig tokenizer give you any ideas for SIMD searching of semicolons? [tholmes](https://ziggit.dev/u/tholmes) 3 Before I went with a MapReduce implementation for the multi-threaded approach, I tried using one hash map with a mutex. However, this resulted in poor performance and it also caused a lot bugs (skill issue I know). This roughly matches my experience with mutex. Recently I wrote a program to convert DDS textures to VTF (Valve Texture Format). I was able to use multithreading to optimise reading the DDS textures from the input directory (since I was decoding DXT1 and DXT5 with code I wrote myself / stole off the Internet), but to write the output VTF files I was depending on [VTFLib](https://nemstools.github.io/pages/VTFLib-Download.html), which is not threadsafe. What this meant was that in order to safely write a VTF, I had to use a mutex to halt all other threads while the external library did its work, creating an unnecessary performance bottleneck. My solution was to have the multi-threaded DDS parser code populate an `ArrayList()` of structures that contained pixels, width, height and format of the output VTF, then do a single-threaded loop over that `ArrayList()` to make calls to VTFLib and actually save the files. Just so you know Zig 0.16 and 0.17 have disabled auto vectorization because of a miscompilation in LLVM 21 that didn’t got fixed until LLVM 23. So your program should get faster on 0.18 when auto vectorization is reenabled. I’m also interested in your changes to the std reader