Pi3B thermal throttling

[clivem]

You might want to consider throttling the Pi3B lower than 600MHz from the VC firmware.

This is with a 10mm high Pimoroni ali heatsink fitted to Pi3B, in the official case, 4 cpu cores being stressed, and it appears, that even though the temp is still just shy of 91degC, the firmware won't throttle any lower than the base 600MHz.

$ vcgencmd measure_temp && vcgencmd measure_clock arm
temp=90.8'C
frequency(45)=600000000

[popcornmix]

Are you testing with latest rpi-update firmware? There have been some tweaks since launch.
Can you show output of vcgencmd get_config int and say what you are running to stress it?

[clivem]

cpuburn-a53 generates the most heat!

$ vcgencmd version
Mar 7 2016 17:08:55
Copyright (c) 2012 Broadcom
version 552adf40d2c18ab95fbfbbca990d303a170f3d74 (clean) (release)

$ vcgencmd get_config int
arm_freq=1200
audio_pwm_mode=1
audio_sdm_mod_order=2
config_hdmi_boost=5
core_freq=250
desired_osc_freq=0x36ee80
disable_audio_dither=1
disable_commandline_tags=2
disable_l2cache=1
emmc_pll_core=1
force_eeprom_read=1
force_pwm_open=1
framebuffer_ignore_alpha=1
framebuffer_swap=1
gpu_freq=300
hdmi_drive=2
hdmi_force_cec_address=65535
init_uart_clock=0x2dc6c00
lcd_framerate=60
max_usb_current=1
over_voltage_avs=0x1cfde
overscan_bottom=47
overscan_left=47
overscan_right=47
overscan_top=47
pause_burst_frames=1
program_serial_random=1
sdram_freq=450
sdtv_aspect=1
temp_limit=85

[clivem]

$ vcgencmd measure_temp && vcgencmd measure_clock arm
temp=90.8'C
frequency(45)=600000000

$ vcgencmd version
Mar 9 2016 18:12:03
Copyright (c) 2012 Broadcom
version 3a754304b032a5298ee7889b179c667bbc75dec5 (clean) (release)

[popcornmix]

Can you confirm that vcgencmd measure_volts is returning 1.2V

[clivem]

$ vcgencmd measure_volts
volt=1.2000V

[robingroppe]

Wow. That thing is getting really hot. I cannot get it any hotter than 70deg C with the powersave governor selected.

[clivem]

Yep, after leaving it overnight, it's now > 100degC, while throttled to 600MHz. I really do think the firmware should throttle lower than 600MHz if temp > 85degC.

Fri 11 Mar 11:16:04 GMT 2016
temp=101.0'C
frequency(45)=600000000

[popcornmix]

On my pi3 with your set up, the temperature is constrained to ~85'C (86'C is the highest I see). The arm is mostly held at 600MHz but occasionally gets to about 800MHz.
This is without a heat sink and with no case. What effect does removing the case lid and/or removing the whole case have?

Can you test with this firmware: https://dl.dropboxusercontent.com/u/3669512/temp/firmware_thermal.zip
It should allow the arm to be limited down to 300MHz. Would be interesting to know how low it gets for you.

[robingroppe]

I dont think that it would help. I have tested a few things over the last
few days. Reducing the clock to 400mhz has no impact on temerature neither
have i noticed a difference with over_voltage=-2.
Am 11.03.2016 12:20 schrieb "Clive Messer" notifications@github.com:

Yep, after leaving it overnight, it's now > 100degC, while throttled to
600MHz. I really do think the firmware should throttle lower than 600MHz if
temp > 85degC.

Fri 11 Mar 11:16:04 GMT 2016
temp=101.0'C
frequency(45)=600000000

—
Reply to this email directly or view it on GitHub
#1337 (comment).

[robingroppe]

Cool! Hopefully ;) I will try that too.
Am 11.03.2016 12:58 schrieb "popcornmix" notifications@github.com:

On my pi3 with your set up, the temperature is constrained to ~85'C (86'C
is the highest I see). The arm is mostly held at 600MHz but occasionally
gets to about 800MHz.
This is without a heat sink and with no case. What effect does removing
the case lid and/or removing the whole case have?

Can you test with this firmware:
https://dl.dropboxusercontent.com/u/3669512/temp/firmware_thermal.zip
It should allow the arm to be limited down to 300MHz. Would be interesting
to know how low it gets for you.

—
Reply to this email directly or view it on GitHub
#1337 (comment).

[popcornmix]

@clivem can you report output of:

for i in 1 2 8 10 11 14; do vcgencmd read_ring_osc $((100+$i)); done
for i in 1 2 8 10 11 14; do vcgencmd read_ring_osc $((200+$i)); done

[clivem]

Will try your test firmware next.....

$ for i in 1 2 8 10 11 14; do vcgencmd read_ring_osc $((100+$i)); done
read_ring_osc(101)=16.150MHz (@1.2000V)
read_ring_osc(102)=2.836MHz (@1.2000V)
read_ring_osc(108)=16.669MHz (@1.2000V)
read_ring_osc(110)=2.818MHz (@1.2000V)
read_ring_osc(111)=2.926MHz (@1.2000V)
read_ring_osc(114)=3.106MHz (@1.2000V)

$ for i in 1 2 8 10 11 14; do vcgencmd read_ring_osc $((200+$i)); done
read_ring_osc(201)=19.588MHz (@1.3000V)
read_ring_osc(202)=3.280MHz (@1.3000V)
read_ring_osc(208)=20.194MHz (@1.3000V)
read_ring_osc(210)=3.259MHz (@1.3000V)
read_ring_osc(211)=3.373MHz (@1.3000V)
read_ring_osc(214)=3.600MHz (@1.3000V)

[clivem]

OK, running your test firmware... Will look again in 10 mins. (cpuburn-a53 running on 4 cores)

$ while true; do echo date && vcgencmd measure_temp && vcgencmd measure_clock arm && vcgencmd measure_clock core; sleep 1; done
Fri 11 Mar 13:19:09 GMT 2016
temp=82.7'C
frequency(45)=600000000
frequency(1)=250000000
Fri 11 Mar 13:19:10 GMT 2016
temp=83.8'C
frequency(45)=874000000
frequency(1)=400000000
Fri 11 Mar 13:19:11 GMT 2016
temp=86.0'C
frequency(45)=710000000
frequency(1)=400000000
Fri 11 Mar 13:19:12 GMT 2016
temp=85.4'C
frequency(45)=600000000
frequency(1)=250000000
Fri 11 Mar 13:19:13 GMT 2016
temp=84.4'C
frequency(45)=600000000
frequency(1)=250000000

[clivem]

OK, starting to see CPU speed drop below 600MHz.

temp=86.0'C
frequency(45)=593000000
frequency(1)=250000000
Fri 11 Mar 13:22:28 GMT 2016
temp=86.0'C
frequency(45)=589000000
frequency(1)=250000000
Fri 11 Mar 13:22:30 GMT 2016
temp=86.0'C
frequency(45)=593000000
frequency(1)=250000000
Fri 11 Mar 13:22:31 GMT 2016
temp=86.0'C
frequency(45)=583000000
frequency(1)=250000000
Fri 11 Mar 13:22:32 GMT 2016
temp=86.5'C
frequency(45)=563000000
frequency(1)=250000000
Fri 11 Mar 13:22:33 GMT 2016
temp=86.5'C
frequency(45)=588000000
frequency(1)=250000000
Fri 11 Mar 13:22:34 GMT 2016
temp=86.0'C
frequency(45)=582000000
frequency(1)=250000000
Fri 11 Mar 13:22:35 GMT 2016
temp=86.5'C
frequency(45)=588000000
frequency(1)=250000000

[clivem]

With 10mm high passive heatsink...
Fri 11 Mar 13:46:26 GMT 2016
temp=86.5'C
frequency(45)=559000000
frequency(1)=250000000

Without heatsink ....
Fri 11 Mar 13:47:12 GMT 2016
temp=87.0'C
frequency(45)=498000000
frequency(1)=250000000