You should probably ask the author then. There are a bunch of links to various socials on the bottom of the post.

Hello, author here. Just to clarify, I wasn't saying that this has any perf impact per se. I was trying to see why syscall showed up quite a bit in the profile, when reading a large file, no matter what buffer size I pass in. Rather than spend time finishing the actual work, I spent way too much time trying to understand the reason for the limit.