From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Paul Thomas <pthomas8589@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
linux-rt-users <linux-rt-users@vger.kernel.org>,
dunc.mcphie@gmail.com, Anders Roxell <anders.roxell@linaro.org>
Subject: Re: poor cyclictest results with 5.0 series rt for arm64
Date: Thu, 15 Aug 2019 10:29:55 +0200 [thread overview]
Message-ID: <20190815082955.olo3phbqj6disk3q@linutronix.de> (raw)
In-Reply-To: <CAD56B7ezpaONhXCddu6RTE33-iXG7+J=xf417xu_uT-YKPV6RQ@mail.gmail.com>
On 2019-08-14 13:04:21 [-0400], Paul Thomas wrote:
> Hi Sebastian,
Hi Paul,
> The attachment is here:
> https://bugzilla.kernel.org/attachment.cgi?id=284391
both traces have `printk' in it. Could you please explain what it is
doing? It should print something to the console. The printk code in
v4.19 vs later changed and now (by default) ERR levels are printed
immediately and will cause latency spikes.
This would explain the spike but I don't understand how lazy preempt is
related here.
> We don't actually need Lazy Preempt, so now that we know what the
> issues is we can just turn it off in the config? However I suspect
> everyone wants to get to the bottom of what's going on at this point?
There is no option for lazy-preemption. And yes, we should figure out
what is causing this.
> thanks,
> Paul
Sebastian
next prev parent reply other threads:[~2019-08-15 8:29 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-12 11:18 poor cyclictest results with 5.0 series rt for arm64 Paul Thomas
[not found] ` <CAD56B7c2=95r7r-6tr0Mby8jSeuQPDNSd4LELnUw1LVRn9Rqew@mail.gmail.com>
2019-07-12 11:32 ` Paul Thomas
2019-07-16 20:24 ` Thomas Gleixner
2019-07-16 21:50 ` Paul Thomas
2019-07-16 23:14 ` Thomas Gleixner
2019-07-17 0:44 ` Paul Thomas
2019-07-17 8:03 ` Thomas Gleixner
2019-07-17 8:10 ` Thomas Gleixner
2019-07-17 9:02 ` Thomas Gleixner
2019-07-17 10:21 ` Thomas Gleixner
2019-07-17 22:28 ` Paul Thomas
2019-08-13 9:53 ` Sebastian Andrzej Siewior
2019-08-13 18:02 ` Paul Thomas
2019-08-14 11:26 ` Sebastian Andrzej Siewior
2019-08-14 16:17 ` [PATCH RT] arm64: preempt: Check preemption level before looking at lazy-preempt Sebastian Andrzej Siewior
2019-08-14 16:17 ` [PATCH RT] x86: " Sebastian Andrzej Siewior
2019-08-14 17:04 ` poor cyclictest results with 5.0 series rt for arm64 Paul Thomas
2019-08-15 8:29 ` Sebastian Andrzej Siewior [this message]
2019-08-15 12:33 ` John Ogness
2019-08-15 13:30 ` Paul Thomas
2019-08-15 13:42 ` Sebastian Andrzej Siewior
2019-08-15 13:52 ` Paul Thomas
2019-08-15 14:19 ` Sebastian Andrzej Siewior
2019-08-15 15:12 ` Paul Thomas
2019-08-15 15:15 ` Sebastian Andrzej Siewior
2019-08-15 15:31 ` Paul Thomas
2019-08-15 18:00 ` Paul Thomas
2019-08-15 18:57 ` Sebastian Andrzej Siewior
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