linux-kernel - Re: [PATCH v2 6/6] sched: Default enable HRTICK

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Message-ID: <20260122123117.GA1389473@pauld.westford.csb>
Date: Thu, 22 Jan 2026 07:31:17 -0500
From: Phil Auld <pauld@...hat.com>
To: Peter Zijlstra <peterz@...radead.org>
Cc: tglx@...utronix.de, arnd@...db.de, anna-maria@...utronix.de,
	frederic@...nel.org, luto@...nel.org, mingo@...hat.com,
	juri.lelli@...hat.com, vincent.guittot@...aro.org,
	dietmar.eggemann@....com, rostedt@...dmis.org, bsegall@...gle.com,
	mgorman@...e.de, vschneid@...hat.com, linux-kernel@...r.kernel.org,
	oliver.sang@...el.com
Subject: Re: [PATCH v2 6/6] sched: Default enable HRTICK

On Thu, Jan 22, 2026 at 12:40:54PM +0100 Peter Zijlstra wrote:
> On Wed, Jan 21, 2026 at 05:24:44PM -0500, Phil Auld wrote:
> > Hi Peter,
> > 
> > On Wed, Jan 21, 2026 at 05:20:16PM +0100 Peter Zijlstra wrote:
> > > ... for generic entry architectures. This decouples preemption from
> > > CONFIG_HZ, leaving only the periodic load-balancer and various
> > > accounting things relying on the tick.
> > > 
> > > Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
> > > ---
> > >  kernel/sched/features.h |    5 +++++
> > >  1 file changed, 5 insertions(+)
> > > 
> > > --- a/kernel/sched/features.h
> > > +++ b/kernel/sched/features.h
> > > @@ -63,8 +63,13 @@ SCHED_FEAT(DELAY_ZERO, true)
> > >   */
> > >  SCHED_FEAT(WAKEUP_PREEMPTION, true)
> > >  
> > > +#ifdef TIF_HRTIMER_REARM
> 
> Arguably this should be CONFIG_GENERIC_ENTRY I suppose
> 
> > > +SCHED_FEAT(HRTICK, true)
> > > +SCHED_FEAT(HRTICK_DL, true)
> > > +#else
> > >  SCHED_FEAT(HRTICK, false)
> > >  SCHED_FEAT(HRTICK_DL, false)
> > > +#endif
> > 
> > I maybe be missing something. But the title of this patch
> > and the above code do not seem to match.
> 
> You mean it only default enables it for a subset of architectures?
>

Nope, I mean I can't read... nevermind.


Cheers,
Phil

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