Re: SCHED_YIELD again

Borislav Deianov (borislav@lix.polytechnique.fr)
Sun, 10 Oct 1999 02:03:53 +0200

On Sat, Oct 09, 1999 at 05:46:39PM -0600, Richard Gooch wrote:
> Borislav Deianov writes:
> > As has been pointed out before, sched_yield currently doesn't work
> > for SCHED_RR processes. There was a patch to fix this about two
> > months ago by Artur Skawina but, as far as I can tell, it was
> > ignored (probably because it included the controversial SCHED_IDLE
> > support). So I'm having another go.
>
> IIRC, that patch was to force a SCHED_RR (or SCHED_FIFO) process to
> give up the CPU if it calls sched_yield(), and allow a SCHED_OTHER
> process to run.

I think this is not the case. Here is a link to his patch:
http://www.deja.com/getdoc.xp?AN=507504549&fmt=text

> If this is the same patch, then it should be rejected. The premise is

This is not the same patch.

> flawed. POSIX.4 states that RT processes will always run in preference
> to SCHED_OTHER. A RT process which does sched_yield() *should not*
> give up it's CPU to a SCHED_OTHER process.

Agreed. With my patch a RT process will only yield to another RT
process with the same or higher priority.

Best,
Borislav

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