We are all familiar with IP addresses such as
192.168.0.1. They are typically written as four numbers in the range 0 to 255 inclusive, separated by dots. In C#, you can parse them with the standard library using IPAddress.TryParse. Pedantic people are quick to point out that IP addresses can take different forms: they can be IPv6 or IPv4 and there are many weird ways to write an IPv4 address. But for the purpose of performance optimization, we care about the common case. The common case is strings such as 192.168.0.1 or 12.121.244.111. Our processors are capable of data parallelism, meaning that they have instructions (called SIMD) that can process several bytes at once, at least 16 bytes, sometimes more. A few years ago, I showed that you can parse IPv4 addresses with SIMD. I have been revisiting this idea with AVX-512, the instruction set that…https://lemire.me/blog/2026/08/19/parsing-ip-addresses-in-c-at-crazy-speeds/
