I've come across 20+ year old kernel code I need to understand/debug/optimize. I certainly didn't write it 20 years ago, but I was there and around and can und

I've come across 20+ year old kernel code I need to understand/debug/optimize. I certainly didn't write it 20 years ago, but I was there and around and can understand the motivations which is helpful. Right around then, most open source kernels started doing a lot of performance work on sockets. Some of which has stood up until recently, but some things look silly with today's eyes. You could set the port number hash length to more than 16-bits, which doesn't make sense... But they added it to get 2 or 4 bits of hashing in 2000, and it worked enough that nobody changed it. Things like that.