[Xenomai] Long time system slow down on imx6

Johann Obermayr johann.obermayr at sigmatek.at
Mon Dec 12 15:49:30 CET 2016


Am 12.12.2016 um 15:35 schrieb Marco Baracchi:
> Sorry I hope this format is more readable
>
> 12.12.2016, 15:31, "Marco Baracchi" <cormabara at yandex.com>:
>> Sorry I hope this is the correct way to add a mail to this thread inside mailing list:
>>
>> What you mean with "lost wakeup problem" ?
Ask google, you get many results.

>>
>> What we are checking is a timer tick missing:
>>
>> root at deimo-staubli ~$ cat /proc/timer_list
i don't know timer_list yet.
i need to look more closely.
>>
>> Timer List Version: v0.6
>>
>> HRTIMER_MAX_CLOCK_BASES: 3
>>
>> now at 158072087097365 nsecs
>>
>> cpu: 0
>>
>> clock 0:
>>
>>    .base:       80ba8380
>>
>>    .index:      0
>>
>>    .resolution: 1 nsecs
>>
>>    .get_time:   ktime_get
>>
>>    .offset:     0 nsecs
>>
>> active timers:
>>
>> #0: <80ba88a0>, tick_sched_timer, S:01
>>
>> # expires at 158034760000000-158034760000000 nsecs [in -37327097365 to -37327097365 nsecs]
>>
>> #1: <8fb57f40>, hrtimer_wakeup, S:01
>>
>> # expires at 158034782298842-158034782348842 nsecs [in -37304798523 to -37304748523 nsecs]
>>
>> #2: <8f201ad0>, hrtimer_wakeup, S:01
>>
>> # expires at 159434496114473-159434496164473 nsecs [in 1362409017108 to 1362409067108 nsecs]
>>
>> #3: <8f20bad0>, hrtimer_wakeup, S:01
>>
>> # expires at 159439053136473-159439057697464 nsecs [in 1366966039108 to 1366970600099 nsecs]
>>
>> clock 1:
>>
>>    .base:       80ba83b8
>>
>>    .index:      1
>>
>>    .resolution: 1 nsecs
>>
>>    .get_time:   ktime_get_real
>>
>>    .offset:     1481376344107425663 nsecs
>>
>> active timers:
>>
>> clock 2:
>>
>>    .base:       80ba83f0
>>
>>    .index:      2
>>
>>    .resolution: 1 nsecs
>>
>>    .get_time:   ktime_get_boottime
>>
>>    .offset:     0 nsecs
>>
>> active timers:
>>
>>    .expires_next   : 158034760000000 nsecs
>>
>>    .hres_active    : 1
>>
>>    .nr_events      : 22078740
>>
>>    .nr_retries     : 51929
>>
>>    .nr_hangs       : 0
>>
>>    .max_hang_time  : 0 nsecs
>>
>>    .nohz_mode      : 0
>>
>>    .idle_tick      : 0 nsecs
>>
>>    .tick_stopped   : 0
>>
>>    .idle_jiffies   : 0
>>
>>    .idle_calls     : 0
>>
>>    .idle_sleeps    : 0
>>
>>    .idle_entrytime : 0 nsecs
>>
>>    .idle_waketime  : 0 nsecs
>>
>>    .idle_exittime  : 0 nsecs
>>
>>    .idle_sleeptime : 0 nsecs
>>
>>    .iowait_sleeptime: 0 nsecs
>>
>>    .last_jiffies   : 0
>>
>>    .next_jiffies   : 0
>>
>>    .idle_expires   : 0 nsecs
>>
>> jiffies: 15773475
>>
>> Tick Device: mode:     1
>>
>> Per CPU device: 0
>>
>> Clock Event Device: mxc_timer1
>>
>> max_delta_ns:   4294967295
>>
>> min_delta_ns:   85000
>>
>> mult:           1
>>
>> shift:          0
>>
>> mode:           3
>>
>> next_event:     158034760000000 nsecs
>>
>> set_next_event: xnarch_next_htick_shot
>>
>> set_mode:       xnarch_switch_htick_mode
>>
>> event_handler:  hrtimer_interrupt
>>
>> retries:        0
>>
>> As you can see the next event is in the past, timer mxc_timer1 seems to have missed a tick.
>>
>> You mean your system is locked into a SELECT system call ?
>>
>> 1ms is the period of your periodic thread ?
>>
>> 12.12.2016, 12:00, "xenomai-request at xenomai.org" <xenomai-request at xenomai.org>:
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>>> Today's Topics:
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>>>     1. Re: Long time system slow down on imx6 (Johann Obermayr)
>>>
>>> ----------------------------------------------------------------------
>>>
>>> Message: 1
>>> Date: Mon, 12 Dec 2016 11:16:33 +0100
>>> From: Johann Obermayr <johann.obermayr at sigmatek.at>
>>> To: Xenomai at xenomai.org
>>> Subject: Re: [Xenomai] Long time system slow down on imx6
>>> Message-ID: <f07822d2-e30a-d394-bae6-bdf776c0f03a at sigmatek.at>
>>> Content-Type: text/plain; charset=utf-8; format=flowed
>>>
>>> Am 09.12.2016 um 23:42 schrieb Marco:
>>>>       We are notice a very strange problem on a imx6 with kernel
>>>>       Linux3.0.35-4.1.0 + xenomai_2.6.4. After machine runs for 8 - 10 hours
>>>>       we found the system blocked in may different ways (user interface
>>>>       tcp/ip interface ecc..)
>>>>
>>>>       ?
>>>>
>>>>       We check into /proc/timer_list and we found the next event was
>>>>       scheduled in the past.
>>>>
>>>>       ?
>>>>
>>>>       We found some items about timer blocked but all the patches indicated
>>>>       was already applied.
>>>>
>>>>       ?
>>>>
>>>>       Maybe someone have seen a similar problem ?
>>>>   _______________________________________________
>>>>   Xenomai mailing list
>>>>   Xenomai at xenomai.org
>>>>   https://xenomai.org/mailman/listinfo/xenomai
>>> Hello,
>>>
>>> i don't known if it is the same problem.
>>> But we search a lost wakeup problem with "select" and a short timeout. (1ms)
>>>
>>> Regards
>>>     Johann
>>>
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At this time, we make many test, if this is a problem with xenomai, or a 
pure linux problem.
We use select with a fdevent for a releaxed wait. And sometime the task 
will hang in the select function.

do you use select with short timeouts in your code ?

regards
   Johann



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