From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Martin.Wirth@dlr.de
Cc: linux-rt-users@vger.kernel.org
Subject: Re: Large latencies with 4.4.1-rt6
Date: Thu, 25 Feb 2016 16:29:30 +0100 [thread overview]
Message-ID: <20160225152930.GC16161@linutronix.de> (raw)
In-Reply-To: <1A2AF5F768264E479963C4D8C015EB691B692C5C@dlrexmbx03.intra.dlr.de>
* Martin.Wirth@dlr.de | 2016-02-19 17:02:20 [+0000]:
>Hi,
Hi,
>I today switched from 4.1.15-rt17 to 4.4.1-rt6.
>Now I'm seeing large latencies of more than 1 ms.
>They occur sporadic ( every few minutes) and show up for example running
>
>cyclictest -l10000000 -m -Sp99 -i200
>
>I tried to catch a trace and got the following:
>
>
> <...>-3709 2d...2.. 2us : set_next_entity <-pick_next_task_fair
> <...>-3709 2d...2.. 2us : update_stats_wait_end <-set_next_entity
> firefox-3736 2d...2.. 3us : finish_task_switch <-__schedule
> firefox-3736 2d...2.. 3us#: _raw_spin_unlock_irq <-finish_task_switch
> firefox-3736 2d...... 1091us : smp_apic_timer_interrupt <-apic_timer_interrupt
> firefox-3736 2d...... 1092us : irq_enter <-smp_apic_timer_interrupt
>Does the above trace ring a bell or is it useless?
This does not ring a bell. According to the trace your CPU took a break
after the unlock until the next interrupt. If this a fucntion trace I
would expect some functions after that.
You could try the v4.4 line as of:
v4.4-rt2
v4.4-rt3
v4.4.1-rt5
to see if I introduced this somewhere by accident. However I haven't seen
this on any of my boxes.
>Thanks,
>
>Martin
Sebastian
next prev parent reply other threads:[~2016-02-25 15:29 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-19 17:02 Large latencies with 4.4.1-rt6 Martin.Wirth
2016-02-25 12:34 ` Tim Sander
2016-02-25 12:47 ` AW: " Martin.Wirth
2016-02-25 12:52 ` Tim Sander
2016-02-25 15:29 ` Sebastian Andrzej Siewior [this message]
2016-02-25 16:08 ` Martin.Wirth
2016-02-25 16:29 ` Sebastian Andrzej Siewior
2016-02-29 17:02 ` AW: " Martin.Wirth
2016-02-29 21:05 ` Thomas Gleixner
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