Temperature too high when high overload

[jb]

Christian Mangin <christian.mangin <at> gmail.com> writes:

> 
> Le 27.08.2012 08:44, Mike Manilone a écrit :
> > Hi all,
> >
> > I just switched from Fedora Linux to FreeBSD. But I noticed a problem,
> > the CPU temperature will be very high when the load is high.
> > Especially while I am building C++ programs. It shut down for even 3
> > times while I was building Firefox/Thunderbird, just because of high
> > temperature (86.5C).
> > ...
> I used to have the same problem with my laptop (i5) and this can be
> fixed by lowering the temperature threshold for passive cooling. (_PSV)
> 
> hw.acpi.thermal.user_override=1
> hw.acpi.thermal.tz0._PSV=80C
> 
> You should try to adjust _PSV to be significantly lower (> 15-20C) than
> the _CRT (critical shutdown temp) so that _CRT is never reached.
> 
> Christian

I too have the same problem (Lenovo dual core r61i).
You should see the relevant data before making any changes - below it is
explained why.

This is my data:
$ sysctl -a | grep -i thermal
hw.acpi.thermal.min_runtime: 0
hw.acpi.thermal.polling_rate: 10
hw.acpi.thermal.user_override: 0
hw.acpi.thermal.tz0.temperature: 42.0C
hw.acpi.thermal.tz0.active: -1
hw.acpi.thermal.tz0.passive_cooling: 0
hw.acpi.thermal.tz0.thermal_flags: 0
hw.acpi.thermal.tz0._PSV: -1
hw.acpi.thermal.tz0._HOT: -1
hw.acpi.thermal.tz0._CRT: 127.0C
hw.acpi.thermal.tz0._ACx: -1 -1 -1 -1 -1 -1 -1 -1 -1 -1
hw.acpi.thermal.tz0._TC1: -1
hw.acpi.thermal.tz0._TC2: -1
hw.acpi.thermal.tz0._TSP: -1
hw.acpi.thermal.tz1.temperature: 42.0C
hw.acpi.thermal.tz1.active: -1
hw.acpi.thermal.tz1.passive_cooling: 1
hw.acpi.thermal.tz1.thermal_flags: 0
hw.acpi.thermal.tz1._PSV: 95.5C
hw.acpi.thermal.tz1._HOT: -1
hw.acpi.thermal.tz1._CRT: 100.0C
hw.acpi.thermal.tz1._ACx: -1 -1 -1 -1 -1 -1 -1 -1 -1 -1
hw.acpi.thermal.tz1._TC1: 5
hw.acpi.thermal.tz1._TC2: 4
hw.acpi.thermal.tz1._TSP: 600
dev.acpi_tz.0.%desc: Thermal Zone
dev.acpi_tz.1.%desc: Thermal Zone
dev.p4tcc.0.%desc: CPU Frequency Thermal Control
dev.p4tcc.1.%desc: CPU Frequency Thermal Control
$

As you can see in my case:
hw.acpi.thermal.tz0.passive_cooling: 0
which is NOT available (so obviously any settings in tz0 zone are irrelevant).
This is explained here:
ACPI_THERMAL(4):
...
     hw.acpi.thermal.tz%d.passive_cooling
             If set to 1, passive cooling is enabled.  It does cooling without
             fans using cpufreq(4) as the mechanism for controlling CPU speed.
             Default is enabled for tz0 where it is available.
...

In my case tz1 zone is available and active.

jb