PowerMac G5 quad-core, CPU A1 DIODE TEMP: 90.8 C (for example): How to handle? [more data]

[Justin Hibbits]

On Thu, 15 Jan 2015 14:33:22 -0800
Mark Millard <markmi at dsl-only.net> wrote:

> For a well-operating PowerMac G5 quad-core for recording over 30
> minutes, sampling about once a second, starting idle and doing "make
> -j 8 buildworld buildkernel":
> 
> Low value to high value (for type of value to get idea of range
> expected)...
> 
> dev.smusat.0.cpu_a0_diode_temp: 38.8C to
> dev.smusat.1.cpu_b1_diode_temp: 68.7C
> 
> dev.smu.0.fans.cpu_a_intake.rpm: 484 to
> dev.smu.0.fans.cpu_a_intake.rpm: 1549
> 
> dev.smu.0.fans.cpu_a_pump.rpm: 1235 to dev.smu.0.fans.cpu_a_pump.rpm:
> 2214
> 
> 
> I put the problem PowerMac G5 quad-core in a about 56degF room in
> order to try to have it run longer so I could collect more
> information. This seems to have been enough to keep it somewhat below
> 90degC generally for the CPU diodes over the initial 30 minutes of
> "make -j 8 buildworld buildkernel".
> 
> Low value to high value (for type of value to get idea of range
> happening, limited to the first 30 minutes or so)...
> 
> dev.smusat.0.cpu_a0_diode_temp: 38.2C to
> dev.smusat.0.cpu_a1_diode_temp: 90.2C (Just one 90.2C at that point
> and one dev.smusat.0.cpu_a1_diode_temp: 90.1C but a bunch of
> 89.[5-9]C's.)
> 
> dev.smu.0.fans.cpu_a_intake.rpm: 485 to
> dev.smu.0.fans.cpu_a_intake.rpm: 3184
> 
> dev.smu.0.fans.cpu_a_pump.rpm: 1254 to dev.smu.0.fans.cpu_a_pump.rpm:
> 3636
> 
> Letting it run longer, however, has lead to more 90.[0-9]C's and
> messages like (all but the 1st two are from after the 30 minutes):
> 
> WARNING: Current temperature (CPU A1 DIODE TEMP: 90.2 C) exceeds
> critical temperature (90.0 C); count=1 WARNING: Current temperature
> (CPU A1 DIODE TEMP: 90.1 C) exceeds critical temperature (90.0 C);
> count=1 WARNING: Current temperature (CPU A1 DIODE TEMP: 90.1 C)
> exceeds critical temperature (90.0 C); count=1 WARNING: Current
> temperature (CPU A1 DIODE TEMP: 90.2 C) exceeds critical temperature
> (90.0 C); count=2 WARNING: Current temperature (CPU A1 DIODE TEMP:
> 90.4 C) exceeds critical temperature (90.0 C); count=3 WARNING:
> Current temperature (CPU A1 DIODE TEMP: 90.6 C) exceeds critical
> temperature (90.0 C); count=4 WARNING: Current temperature (CPU A1
> DIODE TEMP: 90.4 C) exceeds critical temperature (90.0 C); count=1
> WARNING: Current temperature (CPU A1 DIODE TEMP: 90.4 C) exceeds
> critical temperature (90.0 C); count=2 WARNING: Current temperature
> (CPU A1 DIODE TEMP: 90.1 C) exceeds critical temperature (90.0 C);
> count=3 WARNING: Current temperature (CPU A1 DIODE TEMP: 90.1 C)
> exceeds critical temperature (90.0 C); count=2 WARNING: Current
> temperature (CPU A1 DIODE TEMP: 90.1 C) exceeds critical temperature
> (90.0 C); count=3 WARNING: Current temperature (CPU A1 DIODE TEMP:
> 90.1 C) exceeds critical temperature (90.0 C); count=1 WARNING:
> Current temperature (CPU A1 DIODE TEMP: 90.1 C) exceeds critical
> temperature (90.0 C); count=1 WARNING: Current temperature (CPU A1
> DIODE TEMP: 90.6 C) exceeds critical temperature (90.0 C); count=2
> 
> It did automatically shut down after about 50 min. The other 3 CPU
> diodes were in the range 68C to 74C or so. A1 just seems to register
> hotter. It ended with the recorded sequence for a1:
> 
> dev.smusat.0.cpu_a1_diode_temp: 89.2C
> dev.smusat.0.cpu_a1_diode_temp: 90.6C
> dev.smusat.0.cpu_a1_diode_temp: 90.6C
> dev.smusat.0.cpu_a1_diode_temp: 90.1C
> dev.smusat.0.cpu_a1_diode_temp: 89.9C
> dev.smusat.0.cpu_a1_diode_temp: 90.1C
> dev.smusat.0.cpu_a1_diode_temp: 90.9C
> dev.smusat.0.cpu_a1_diode_temp: 91.3C
> dev.smusat.0.cpu_a1_diode_temp: 91.1C
> dev.smusat.0.cpu_a1_diode_temp: 91.4C
> dev.smusat.0.cpu_a1_diode_temp: 91.8C
> dev.smusat.0.cpu_a1_diode_temp: 92.0C
> 
> 
> The high fan/pump figures recorded were:
> 
> dev.smu.0.fans.cpu_b_intake.rpm: 3199
> dev.smu.0.fans.cpu_a_intake.rpm: 3200
> dev.smu.0.fans.cpu_b_exhaust.rpm: 3198
> dev.smu.0.fans.cpu_a_exhaust.rpm: 3199
> dev.smu.0.fans.cpu_a_pump.rpm: 3637
> 
> These are all well above those recorded for the well-operating
> PowerMac G5 quad-core.
> 
> ===
> Mark Millard
> markmi at dsl-only.net

Could you try the attached patch? (Untested here, my quad isn't up).
It scales more exponentially, hitting full blast around the thermal
midpoint.  This can obviously be adjusted up or down, but should be a
good starting point.  We should probably also have a backoff algorithm,
to keep the fans going longer after it cools, like OS X does.

- Justin
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