Cooling CPU in software S905X2/S922?

Development Development & Testing
15

If my S912 box is typical it has 2 sets of 4 cores the first set of 4 cores uses
/sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
and is set to ondemand Minimum frequency 1Ghz (1000000) Maximum 1.5Ghz (1512000)
Available Frequencies 100000 250000 500000 667000 1000000 1200000 1512000

The second set of 4 are controlled by
/sys/devices/system/cpu/cpu4/cpufreq/scaling_governor
and is set to ondemand Minimum frequency 1Ghz (1000000) Maximum 1Ghz (100000). So the scaling governor has no effect.
Available Frequencies 100000 250000 500000 667000 1000000

I tried the following but it only makes a couple of degrees C difference as the S912 has already got the ondemand governor enabled. The box does idle at 600Mhz even playing UHD content.

#!/bin/bash
echo 500000 > /sys/devices/system/cpu/cpu4/cpufreq/scaling_min_freq
echo 500000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq

On the S905x2 the default is ‘performance’ so the cpus run flat out all the time so there is a dramatic drop in power/temperature by changing the governor to interactive/schedutil.

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