short time freeze on CURRENT

[Bill Paul]

> Hi!
> 
> I've already posted about it a week ago. About every 10 seconds the
> system freeze for about 0.5 second. I feel it on mplayer, for example,
> and on a keyboard. The system lost my keypresses. I see it on friday's
> CURRENT running on dell d505 notebook. I've tried SCHED_ULE and
> SCHED_4BSD, with and without PREEMTION, and different
> hw.acpi.cpu.cx_lowest. No difference.
> 
> -- 
> DSS5-RIPE DSS-RIPN 2:550/5068 at fidonet 2:550/5069 at fidonet
> mailto:dsh at vlink.ru http://neva.vlink.ru/~dsh/
> 

For the umpity-umpth time, the problem is the ACPI thermal monitoring
thread. You don't have to turn off all of ACPI, you just need to
put this in /boot/loader.conf:

debug.acpi.disabled="thermal"

Reading the system temperature via ACPI seems to take an amazingly long
time, during which I'm guessing interrupts are disabled. Someone with
more ACPI fu than me needs to investigate this, but I guess nobody
cares enough to do it. (The code is, sadly, very convoluted.)

This is also not just a problem with -current: 6.0-RELEASE does
it too. It's also not confined to laptops: in my case, I get it
on my dual Opteron system (in either i386 or amd64 mode).

-Bill

--
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-Bill Paul            (510) 749-2329 | Senior Engineer, Master of Unix-Fu
                 wpaul at windriver.com | Wind River Systems
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              <adamw> you're just BEGGING to face the moose
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