[scns]

Intel uses -o2 or -o3 for Clear Linux packages, depending on which produces faster binaries. Worth checking out, if you want more performance.

[bravetraveler]

They also disable journaling and stuff last I looked. It's fine inspiration, but cargo culture has dangers

They make trades that I'm not sure are advisable

[rurban]

-Os usually is the fastest, better than -Ofast

[kibibu]

Depends on a bunch of things, including cache sizes