[LTP] [PATCH] sched_football: synchronize with kickoff flag to reduce skew

[Li Wang]

On Thu, Sep 4, 2025 at 5:53 PM Cyril Hrubis <chrubis@suse.cz> wrote:

> Hi!
> > >  static void do_setup(void)
> > >  {
> > > +   if (!tst_check_preempt_rt())
> > > +           tst_brk(TCONF, "Test requires real-time kernel");
> >
> > I guess this itself fix many false positives :). I'm ok with requesting
> RT
> > kernel, but just to remind the claim originated from Cyril [1]
> "sched_football
> > is useful not only for testing realtime". So was Cyril wrong?
>
> No Cyril wasn't wrong. The realtime schedulling priorities in kernel are
> completely different thing from realtime kernel patchset.
>

Yes, we can set up processes with SCHED_FIFO or SCHED_RR policies
on the stock kernel, but it's not the same thing as the PREEMPT_RT kernel.

I guess we don't need to do more tries on test with
sched_setscheduler(pid, SCHED_FIFO) situation just to avoid false positives,
because there might be no perfect solution.

So I'd prefer to keep sched_football tested only on real-time kernels.


-- 
Regards,
Li Wang