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From: Thomas Gleixner <tglx@linutronix.de>
To: Juri Lelli <juri.lelli@redhat.com>, bigeasy@linutronix.de
Cc: linux-rt-users@vger.kernel.org, peterz@infradead.org,
	linux-kernel@vger.kernel.org, bristot@redhat.com,
	Juri Lelli <juri.lelli@redhat.com>,
	Anna-Maria Behnsen <anna-maria@linutronix.de>
Subject: Re: [RFC PATCH RT v2 1/2] time/hrtimer: Add PINNED_HARD mode for realtime hrtimers
Date: Sat, 19 Jun 2021 09:56:14 +0200	[thread overview]
Message-ID: <87bl82e19d.ffs@nanos.tec.linutronix.de> (raw)
In-Reply-To: <87k0mqeofg.ffs@nanos.tec.linutronix.de>

On Sat, Jun 19 2021 at 01:35, Thomas Gleixner wrote:
> The wild west of anything which scratches 'my itch' based on 'my use
> case numbers' in Linux ended many years ago and while RT was always a
> valuable playground for unthinkable ideas we definitely tried hard not
> to accept use case specific hacks wihtout a proper justification that it
> makes sense in general.
>
> So why are you even trying to sell this to me?

I wouldn't have been that grumpy if you'd at least checked whether the
task is pinned. Still I would have told you that you "fix" it at the
wrong place.

Why on earth is that nohz heuristic trainwreck not even checking that?
It's not a RT problem and it's not a problem restricted to RT tasks
either. If a task is pinned then arming the timer on a random other CPU
is blatant nonsense independent of the scheduling class.

Thanks,

        tglx

  reply	other threads:[~2021-06-19  7:56 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-16  7:17 [RFC PATCH RT v2 0/2] Add PINNED_HARD mode to hrtimers Juri Lelli
2021-06-16  7:17 ` [RFC PATCH RT v2 1/2] time/hrtimer: Add PINNED_HARD mode for realtime hrtimers Juri Lelli
2021-06-18 23:35   ` Thomas Gleixner
2021-06-19  7:56     ` Thomas Gleixner [this message]
2021-06-21  5:35       ` Juri Lelli
2021-06-16  7:17 ` [RFC PATCH RT v2 2/2] time/hrtimer: Embed hrtimer mode into hrtimer_sleeper Juri Lelli

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