From: Vladimir Oltean <olteanv@gmail.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: paulmck@kernel.org,
Anna-Maria Gleixner <anna-maria@linutronix.de>,
catalin.marinas@arm.com, Alison Wang <alison.wang@nxp.com>,
linux-kernel@vger.kernel.org, leoyang.li@nxp.com,
Peter Zijlstra <peterz@infradead.org>,
vladimir.oltean@nxp.com,
Kurt Kanzenbach <kurt.kanzenbach@linutronix.de>,
mw@semihalf.com, will@kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [RFC PATCH] arm64: defconfig: Disable fine-grained task level IRQ time accounting
Date: Mon, 3 Aug 2020 14:41:12 +0300 [thread overview]
Message-ID: <20200803114112.mrcuupz4ir5uqlp6@skbuf> (raw)
In-Reply-To: <87lfiwm2bj.fsf@nanos.tec.linutronix.de>
Hi Thomas,
On Mon, Aug 03, 2020 at 12:49:36PM +0200, Thomas Gleixner wrote:
> Kurt,
>
> Kurt Kanzenbach <kurt.kanzenbach@linutronix.de> writes:
> > On Thu Jul 30 2020, Vladimir Oltean wrote:
> > OK. I've reproduced it on a Marvell Armada SoC with v5.6 mainline. See
> > splats below. Running with irq time accounting enabled, kills the
> > machine immediately. However, I'm not getting the possible deadlock
> > warnings in 8250 as you did. So that might be unrelated.
> >
> > Unfortunately I have no idea what to debug here.
>
> lets look at the facts we have so far.
>
> 1) When irq accounting is disabled, RT throttling kicks in as
> expected.
>
> 2) With irq accounting the RT throttler does not kick in and the RCU
> stall/lockups happen.
>
> Not much, but there is clearly interaction between irq time accounting
> and scheduler accounting.
>
> Can you please reduce /proc/sys/kernel/sched_rt_runtime_us in steps of
> 50000? At least in theory, reduction should bring the throttling back.
>
> Thanks,
>
> tglx
>
We already know from my original report that reducing
sched_rt_runtime_us to 80% (800000) gives us a stable system.
https://lkml.org/lkml/2020/6/4/1062
What is this telling us?
Thanks,
-Vladimir
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next prev parent reply other threads:[~2020-08-03 11:42 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-29 3:39 [RFC PATCH] arm64: defconfig: Disable fine-grained task level IRQ time accounting Alison Wang
2020-07-29 8:40 ` Kurt Kanzenbach
2020-07-29 8:50 ` [EXT] " Alison Wang
2020-07-29 9:49 ` Vladimir Oltean
2020-07-30 7:23 ` Kurt Kanzenbach
2020-07-30 8:22 ` Vladimir Oltean
2020-08-03 8:04 ` Kurt Kanzenbach
2020-08-03 8:16 ` Vladimir Oltean
2020-08-03 9:51 ` Robin Murphy
2020-08-03 11:38 ` Vladimir Oltean
2020-08-03 11:48 ` Valentin Schneider
2020-08-03 13:24 ` Marc Zyngier
2020-08-03 10:02 ` Thomas Gleixner
2020-08-03 10:49 ` Thomas Gleixner
2020-08-03 11:41 ` Vladimir Oltean [this message]
2020-08-03 15:13 ` Thomas Gleixner
2020-08-03 15:47 ` Valentin Schneider
2020-08-03 16:14 ` Vladimir Oltean
2020-08-03 19:22 ` Thomas Gleixner
2020-08-03 23:59 ` Valentin Schneider
2020-08-05 8:50 ` Dietmar Eggemann
2020-08-05 13:40 ` peterz
2020-08-05 13:56 ` Valentin Schneider
2020-08-05 15:31 ` peterz
2020-08-06 9:41 ` Thomas Gleixner
2020-08-06 11:45 ` peterz
2020-08-06 13:27 ` Paul E. McKenney
2020-08-06 19:03 ` Thomas Gleixner
2020-08-06 20:39 ` Paul E. McKenney
2020-08-06 18:58 ` Thomas Gleixner
2020-08-06 9:34 ` Thomas Gleixner
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