System extremely slow under light load

Bartosz Fabianowski freebsd at
Mon Apr 25 13:21:24 UTC 2011

> I am not sure tz0 is the real thermal zone, especially given values
> of _tc1, _tc2 and _tsp. Temperature value (3001)  looks suspicious as
> well.

I agree. tz0 looks entirely bogus. There is no second fan to control for 
it and I have no idea what it is supposed to be monitoring.

> Can you, by any chance, put your ASL someplace accessible and provide
> a description of what you have done to fix the temperature
> reporting.

Certainly. I have uploaded the files at [1] through [5].

The DSDT source returned by acpidump -d is at [1]. I modified this so 
that it can be compiled back into AML without errors or warnings. This 
modified source is at [2]. It contains no functional changes. The 
thermal zones are still broken. A variant with fixed tz1 is at [3].

For convenience, I have also uploaded diffs between these source files. 
[4] is the diff required to make the source compile (difference between 
[1] and [2]). [5] is the actual change I made to fix tz1 (difference 
between [2] and [3]). As you can see, all I did was to remove a bogus 
function that ends up always returning 0°C.

> As the side note: I have seen and do own pieces of equipment that
> use thermal zones to initiate critical shutdown for various and
> unrelated reasons.

In my case, the thermal zone and its various tripping points do 
correspond to the actual system fan. It is just that the BIOS enforces 
power management itself, ignoring ACPI - except for critical shutdown 
which appears to be triggered by ACPI only.

- Bartosz


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