Messages in this thread | | | Date | Sat, 9 Oct 1999 18:13:09 -0600 | From | Richard Gooch <> | Subject | Re: SCHED_YIELD again |
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Borislav Deianov writes: > 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.
Agreed. But in your patch I saw some that appears to re-introduce a bug I fixed some time ago. You were unconditionally setting SCHED_YIELD in sched_yield(). I made it conditional in the first place because POSIX.4 semantics were not being obeyed.
> > 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.
Are you positive? Can you send me the patch privately again (sorry, I deleted it once I saw the bit I was worried about).
Regards,
Richard.... Permanent: rgooch@atnf.csiro.au Current: rgooch@ras.ucalgary.ca
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