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From: Frederic Weisbecker <frederic@kernel.org>
To: Juri Lelli <juri.lelli@redhat.com>
Cc: fweisbec@gmail.com, tglx@linutronix.de, mingo@kernel.org,
	linux-rt-users@vger.kernel.org, peterz@infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH] tick/sched: update full_nohz status after SCHED dep is cleared
Date: Thu, 21 May 2020 02:44:44 +0200	[thread overview]
Message-ID: <20200521004443.GB15455@lenoir> (raw)
In-Reply-To: <20200520184710.GO10078@localhost.localdomain>

On Wed, May 20, 2020 at 08:47:10PM +0200, Juri Lelli wrote:
> On 20/05/20 19:02, Frederic Weisbecker wrote:
> > On Wed, May 20, 2020 at 06:49:25PM +0200, Juri Lelli wrote:
> > > On 20/05/20 18:24, Frederic Weisbecker wrote:
> > > 
> > > Hummm, so I enabled 'timer:*', anything else you think I should be
> > > looking at?
> > 
> > Are you sure you also enabled timer_expire_entry?
> > Because:
> 
> I run with
> 
> trace-cmd record -e sched_switch -e sched_wakeup -e sched_migrate_task \
> -e 'timer:*' -e 'irq_vectors:*' -e 'irq:softirq*' \
> -e 'irq:irq_handler*' taskset --cpu-list 4-35 ./sysjitter/sysjitter \
> --runtime 10 200
> 
> And
> 
> $ grep ' timer_expire_entry:' trace.txt | wc -l
> 1173
> 
> seems to confirm that the event was indeed enabled, e.g.
> 
> ksoftirqd/11-100   [011]   159.270023: timer_expire_entry:   timer=0xffff9807df8a5a60 function=delayed_work_timer_fn now=4294826418 baseclk=4294825984

That's interesting! I'll see if I can reproduce that with threaded irqs. If not we'll
have to investigate on your machine. We really don't want to trigger timer softirqs
when it's not necessary.

  reply	other threads:[~2020-05-21  0:44 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-20 14:04 [RFC PATCH] tick/sched: update full_nohz status after SCHED dep is cleared Juri Lelli
2020-05-20 16:24 ` Frederic Weisbecker
2020-05-20 16:49   ` Juri Lelli
2020-05-20 17:02     ` Frederic Weisbecker
2020-05-20 18:47       ` Juri Lelli
2020-05-21  0:44         ` Frederic Weisbecker [this message]
2020-05-21 17:00           ` Juri Lelli
2020-06-15 15:05             ` Juri Lelli
2020-06-15 21:07             ` Frederic Weisbecker
2020-06-16  6:57               ` Juri Lelli
2020-06-16 20:46                 ` Frederic Weisbecker
2020-06-29 12:36                   ` Juri Lelli
2020-06-29 12:42                     ` Frederic Weisbecker
2020-06-29 12:53                       ` Juri Lelli

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