Re: [REPORT] cfs-v4 vs sd-0.44

Linus Torvalds
2007-04-21T16:35:43Z

On Sat, 21 Apr 2007, Willy Tarreau wrote:
>
> If you remember, with 50/50, I noticed some difficulties to fork many
> processes. I think that during a fork(), the parent has a higher probability
> of forking other processes than the child. So at least, we should use
> something like 67/33 or 75/25 for parent/child.

It would be even better to simply have the rule:
- child gets almost no points at startup
- but when a parent does a "waitpid()" call and blocks, it will spread
out its points to the childred (the "vfork()" blocking is another case
that is really the same).

This is a very special kind of "priority inversion" logic: you give higher
priority to the things you wait for. Not because of holding any locks, but
simply because a blockign waitpid really is a damn big hint that "ok, the
child now works for the parent".

Linus