My problems with stability on -current

[Alexander Motin]

On 10.05.2011 02:48, Doug Barton wrote:
>>>> I would start from most obvious problems. I need to know more about
>>>> crashes. As usual: how to trigger, stack backtraces, etc.
>>>
>>> Triggering is easy, I can start a buildworld with -j2, and a build of
>>> ports/www/firefox with FORCE_MAKE_JOBS, and within 30 minutes the system
>>> will reboot. I posted a panic message relative to r220282, (-current
>>> archives, 4/4) but kib said it didn't make any sense. Usually I don't
>>> get a panic at all.
>>
>> Could you hint me the thread?
>
> Go to http://www.FreeBSD.org/
> Click 'mailing lists'
> Click 'listed in the FreeBSD Handbook.'
> Click freebsd-current
> Click freebsd-current Archives
> Click April 2011
> search for r220282
> Voila! :)

OK, but URL would be fine also. :) I am agree with kib@ -- the message 
doesn't match the backtrace.

>>>> What's about time problems, I would try to collect more data:
>>>> - show `sysctl kern.eventtimer`, `sysctl kern.timecounter` and verbose
>>>> dmesg outputs;
>>>
>>> http://people.freebsd.org/~dougb/dougb-current-r221566.txt
>>>
>>>> - what eventtimer is used now and does it helps to switch to another
>>>> one with kern.eventtimer.timer sysctl?
>>>
>>> When I was trying to track down the problems last summer I vaguely
>>> remember trying RTC, but eventually we realized that the real problem
>>> was throttling, so I stopped specifying RTC and let it go back to the
>>> default. What do you suggest I try?
>>
>> As I see, now you are using HPET (chosen automatically). I would try
>> switch to the LAPIC. Just make sure to disable C-states if you are
>> enabled them to be sure that LAPIC timer won't stop.
>
> Ok, so kern.eventtimer.timer="LAPIC" in /boot/loader.conf should do
> that, right?

Yes. You can do it in run-time also.

> I don't use C-states (in part as a result of previous investigation) but
> I do use powerd as such:
> powerd_flags="-a adaptive -b adaptive -n adaptive"
>
>>>> - does the timer runs in periodic or one-shot mode and does it helps to
>>>> switch to another one?
>>>
>>> How could I tell, and how would I switch?
>>
>> `sysctl kern.eventtimer.periodic`.
>
> kern.eventtimer.periodic: 0
>
>> And read eventtimers(4) please.
>
> I did that, but I don't see anything in there as to which choice is
> one-shot, and how to change to periodic. I assume 0 is the default,
> which I also assume is one-shot. Does setting that to 1 change to
> periodic? Also, can I safely do this while the system is running, or
> should it be in /boot/loader.conf as well?

Yes, nonzero value means periodic. And yes, changing in run-time is safe.

-- 
Alexander Motin