lsr: ls with io_uring

Kind of fascinating that slashing syscalls by ~35x (versus the `ls -la` benchmark) is "only" worth a 2x speedup

I vaguely remember some benchmark I read a while back for some other io_uring project, and it suggested that io_uring syscalls are more expensive than whatever the other syscalls were that it was being used to replace. It's still a big improvement, even if not as big as you'd hope.

I wish I could remember the post, but I've had that impression in the back of my mind ever since.

These syscalls are mostly through VDSO, so not very costly

The only VDSO-capable calls are clock_gettime, getcpu, getrandom, gettimeofday, and time. (Other architectures have some more, mostly related to signals and CPU cache flushing.)

Can someone try this in a virtual machine? I’d imagine syscalls there to be more expensive.