[kpcyrd]

What about using the filesystem as an optimized dict implementation?

[olmo23]

this is never going to be faster because it requires syscalls

[kpcyrd]

The time you lose at the syscall boundary you may be able to win back during much shorter GC pauses.

[cess11]

Some suggestions that are already in the PR list disable GC.

https://www.php.net/manual/en/function.gc-disable.php