Re: Linux 2.6.25 (coretemp reads high temperatures)
From: Matthew
Date: Tue Apr 29 2008 - 18:59:26 EST
>
> Hi all,
>
> I already answered this thread while ago. I can just confirm what Jean told.
>
>
> >>>> I confirm this.
> >>>> I *know* that temperatures reported now are wrong.
> >
> > And how do you know? The newly reported temperatures could be correct
> > and the previous ones were incorrect (that's actually the case.) The
> > thing is, the temperature is stored as a relative value in the CPU.
> > Relative to what, depends on the CPU model, can be 85°C or 100°C. Up to
> > kernel 2.6.24 we had a set of rules to find out, in 2.6.25 we have a
> > presumably better heuristic. So some people have seen their CPU
> > temperature climb by 15°C and others drop by 15°C, that's expected.
>
> Yes exactly. I decided to move to 0-100C scale, and move the limit too.
> Of course some users with too low jumped to better scale some like you seems to
> complain now.
>
>
> >>> i have watercooling, and well :P when i touch the "tube", its normal
> >>> room temperature, and believe me, i would notice if it was 45.. this is
> >>> with my cpu at idle - at full load on all 4 cores, temp2 says 35, and
> >>> ~60 on coretemp, and THIS i would surely be able to notice over room
> >>> temp :)
> >
> > The coretemp driver reports the CPU _core_ temperature. That's not
> > something you can touch, believe me (unless you are an electron.)
> >
> > Also note that the CPU temperature reported by the IT8718F may or may
> > not match the reality. To make sure, you'd need to know the type of
> > thermal diode expected by the IT8718F, the type of thermal diode in
> > your CPU, compute the correction factor if there is one. And you'd need
> > to know where the thermal diode is exactly. It is most certainly built
> > into the CPU, but some motherboard makers are doing weird things.
> >
> > 22°C seems very low to me, even for water-cooling. Note that
> > non-linearity of thermal diodes makes measurements inaccurate as they
> > get away from the expected operating point. I guess that thermal diodes
> > used in CPUs are calibrated for best results around the expected
> > temperature when using air-cooling, rather than water-cooling.
> >
> >>> any progress on this bug?
> >
> > I still need to be convinced that there is a bug here.
>
> It is not a bug, a max limit changed too, it is just matter how to scale it. The
> temperature is non-physical so comparing it to physical temperature does not
> make any sense. I'm sorry I did not invent this relative temp stuff - Complain
> @intel. They have some calibration of TjMAX for mobiles, but this bit does not
> work for desktops/servers. I tried really hard to get at LEAST some
> documentation so the driver looks like it looks. And not
> guessed/guessed/guessed/how it looked earlier.
>
>
> >
> >>>> The reason is that bios did report same temperatures as coretemp in 2.6.24,
> >>>> moreover some time ago I have run a cpu tool (don't remember its name) on windows
>
> It was most likely coretemp - I'm in contact with the guy. We share infos.
>
>
> >>>> temperature of both cores
> >>>> (I had to run this on windows - intel haven't released
> >>>> drivers for their QST for temperature monitoring from bios - very sad)
> >>>>
> >>>> And the driver did say in kernel log that TJMAX is 85C
> >
> > Which driver, which kernel? As I wrote above, the coretemp heuristic
> > changed in kernel 2.6.25, so the fact that a previous kernel was
> > reporting a different tjmax value is irrelevant. Unless you have
> > additional documentation from Intel, I would tend to believe that the
> > coretemp driver in 2.6.25 is correct. But feel free to report the exact
> > CPU model you have (with CPUID info) to Rudolf, if he gets enough
> > reports about a specific CPU model which most people believe gets the
> > wrong tjmax, he can fix the driver.
>
> Well again, I tried hard at Intel and I really could not get any info on some
> calibration bit. The temperature is non-physical on arbitrary scale. I changed
> that so for some people it jumped to 100C, for some it remained.
>
>
> >>>> Lets at least make a kernel option to override tjmax?
> >
> > That's a possibility for sure, but what we would really need is to
> > adjust the coretemp driver heuristics to always get it right - if
> > that's not already the case, that is. I'll let Rudolf decide anyway.
>
> Well again, Intel swears there is no way how to get the TjMAX for
> desktops/servers. It sucks but this is not my fault.
>
> Thanks,
> Rudolf
>
Hi Rudolf, hi @ all,
so we were just too concerned all the time & even though the
temperatures seem too high there's nothing to worry ?
I'd be more tranquilized if I had the old temperatures ;)
but like lm_sensors's output states - it's not bad until I / we're
getting temperatures from 85°C (?) [in this particular case], ...
@lkml, Linus:
sorry for all the noise ;)
Len,
here's the output of sensors (lm_sensors):
with acpi thermal-support compiled in:
w83627ehf-isa-0290
Adapter: ISA adapter
VCore: +1.12 V (min = +0.00 V, max = +1.74 V)
in1: +12.36 V (min = +13.46 V, max = +13.46 V) ALARM
AVCC: +3.34 V (min = +4.08 V, max = +2.03 V) ALARM
3VCC: +3.34 V (min = +3.92 V, max = +3.95 V) ALARM
in4: +1.70 V (min = +1.53 V, max = +2.04 V)
in5: +1.59 V (min = +2.04 V, max = +1.02 V) ALARM
in6: +5.12 V (min = +6.53 V, max = +6.32 V) ALARM
VSB: +3.26 V (min = +3.06 V, max = +4.08 V)
VBAT: +3.20 V (min = +4.02 V, max = +4.02 V) ALARM
in9: +1.61 V (min = +2.04 V, max = +2.04 V) ALARM
Case Fan: 0 RPM (min = 0 RPM, div = 128)
CPU Fan: 969 RPM (min = 0 RPM, div = 8)
Aux Fan: 3970 RPM (min = 0 RPM, div = 2)
fan4: 0 RPM (min = 83 RPM, div = 128) ALARM
fan5: 1308 RPM (min = 0 RPM, div = 8)
Sys Temp: +39.0°C (high = +123.0°C, hyst = -65.0°C) sensor = thermistor
CPU Temp: +29.0°C (high = +80.0°C, hyst = +75.0°C) sensor = diode
AUX Temp: +121.5°C (high = +80.0°C, hyst = +75.0°C) ALARM sensor
= thermistor
cpu0_vid: +1.350 V
coretemp-isa-0000
Adapter: ISA adapter
Core 0: +60.0°C (high = +84.0°C, crit = +100.0°C)
coretemp-isa-0001
Adapter: ISA adapter
Core 1: +57.0°C (high = +84.0°C, crit = +100.0°C)
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------
and without:
w83627ehf-isa-0290
Adapter: ISA adapter
VCore: +1.30 V (min = +0.00 V, max = +1.74 V)
in1: +12.30 V (min = +13.46 V, max = +13.46 V) ALARM
AVCC: +3.36 V (min = +4.08 V, max = +2.03 V) ALARM
3VCC: +3.34 V (min = +3.92 V, max = +3.95 V) ALARM
in4: +1.70 V (min = +1.53 V, max = +2.04 V)
in5: +1.59 V (min = +2.04 V, max = +1.02 V) ALARM
in6: +5.12 V (min = +6.53 V, max = +6.32 V) ALARM
VSB: +3.26 V (min = +3.06 V, max = +4.08 V)
VBAT: +3.20 V (min = +4.02 V, max = +4.02 V) ALARM
in9: +1.61 V (min = +2.04 V, max = +2.04 V) ALARM
Case Fan: 0 RPM (min = 0 RPM, div = 128)
CPU Fan: 986 RPM (min = 0 RPM, div = 8)
Aux Fan: 3970 RPM (min = 0 RPM, div = 2)
fan4: 0 RPM (min = 83 RPM, div = 128) ALARM
fan5: 1308 RPM (min = 0 RPM, div = 8)
Sys Temp: +39.0°C (high = +123.0°C, hyst = -65.0°C) sensor = thermistor
CPU Temp: +29.0°C (high = +80.0°C, hyst = +75.0°C) sensor = diode
AUX Temp: +117.0°C (high = +80.0°C, hyst = +75.0°C) ALARM sensor
= thermistor
cpu0_vid: +1.375 V
coretemp-isa-0000
Adapter: ISA adapter
Core 0: +60.0°C (high = +84.0°C, crit = +100.0°C)
coretemp-isa-0001
Adapter: ISA adapter
Core 1: +58.0°C (high = +84.0°C, crit = +100.0°C)
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------
it's the completely same temperatures - it had no effect on the
"correctness" of the output
thanks to everyone
Regards
Mat
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