[gitpusher42]

uh, tried most of this

mmap benchmark did basically page touch experiment and cold reads were much slower, unfortunately (10ms vs 3ms)

I tried MADV_WILLNEED, F_RDADVISE and preadv. preadv reduced parallelism because requested experts are rarely adjacent in the file.

pread is still the fastest. And I think Flash-Moe got the same result too