Strange 'hangs' with RELENG_9

[Ian Lepore]

On Thu, 2012-01-19 at 19:14 +0200, Alexander Motin wrote:
> On 19.01.2012 18:51, Oliver Pinter wrote:
> > CC: Alexander Motin
> >
> > On 1/19/12, László KÁROLYI<laszlo at karolyi.hu>  wrote:
> >> László KÁROLYI wrote:
> >>> Ok, couldn't get it through... So here is it, uploaded:
> >>>
> >>> http://www.freeimagehosting.net/s836i
> >> Another screenshot here:
> >>
> >> http://www.freeimagehosting.net/xv26d
> 
> I am not sure how freezes that could be fixed with key press could be 
> related to panics around storage. I would try to go two different ways:
>   - for panics, if dumping is not possible, I would try to resolve 
> address of the "instruction pointer" from both messages with `addr2line 
> -e /path/to/kernel address`.
>   - for freezes I would try to look on eventtimers(4) subsystem: check 
> what timer is used, try to switch to different one, try to switch into 
> periodic mode.
> 
> Since cause of siis timeouts in SATA2 mode is also unclear, I can't also 
> exclude that it may be somehow related.

The new eventtimers was also the first thing that came to my mind, but I
couldn't quickly find the right way to boot with a different timer.  

I saw in the eventtimers(7) manpage that there's a sysctl to change the
timer, but when I used it the system timing went completely wonky (ntpd
reported it was off by many seconds, a few seconds after I changed it).
When I just tried it again the system locked up and had to be power
cycled.  (I'm trying this on old hardware where my only choices are
i8254 and RTC, and changing to RTC apparently doesn't work well.)  So I
didn't want to recommend it to someone else. :)

For both eventtimers and timecounters, I think it'd be nice if a tunable
or hint could let the user override the quality number.  But maybe
there's already some better way of influencing the choices the kernel
makes?

-- Ian