02-23-2020, 04:17 PM
(This post was last modified: 02-23-2020, 09:20 PM by Der Geist der Maschine.)
Power measurements of kernel builds on X cores with make -jX. [Note, the base system is booted off an SD card with the kernel source code located on the eMMC card. Eventually, I will redo the measurements when booted straight from eMMC].
-j1: 10.0W +/- 0.5W (0 ... 07.0W with screen disabled)
-j2: 12.7W +/- 0.5W (0 ... 09.6W with screen disabled)
-j3: 13.7W +/- 0.5W (0 ... 10.2W with screen disabled)
-j4: 14.3W +/- 0.5W (0 ... 11.2W with screen disabled)
-j5: 15.0W /- 0.5W (0 ... 11.3W with screen disabled)
-j6: 15.0W /- 0.5W (0. .. 11.4W with screen disabled)
When the screen is turned on, power consumption is quite constant with a variance of +/- 0.5W. It's puzzling that occasionally no power is consumed for a few seconds when the screen is turned off. Maybe the battery is taking over during these short intervals?
The external power supply can provide up to 15W. Utilizing 4 cores, the system requires from time to time almost all that power and while utilizing 5 or 6 core, the system requires all the time all that power and probably occasionally even more. This helps explaining the sudden drops in battery charge from 100% to 91% on systems under load (there are are a few threads here on this board).
I also noticed weird things going on which are barely explainable [the actual timestamps are rough guesses. Numbers for the sake of numbers]:
t=00min. I stress the system with make -j5. Power consumption 15W
t=10min. I continue stressing the system with make -j5: Power consumption goes to 0W.
t=11min. I stop the make -j5. Power consumption remains at 0W.
t=20min. Power consumption goes to 13W.
t=40min. Over the last 20 min, the power consumption went slowly down from 13W eventually reaching 8.4W. 8.4W also the power consumption of a freshly booted system.
I gain the impression that at t=10min, the internal battery may have taken over and then from t=20 to 40, the power supply charged back the internal battery. I did not see any capacity drops on /sys/class/power_supply/cw2015-battery/charge, though. Maybe the charge dropped by less than 0.5% keeping the rounded value of 100?
Let's focus on display off (without load): When the display is off, there is an oscillation of 0W for 2 seconds and 5.4W for two seconds. Do here really main power and battery flip flop charging the Pinebook Pro?
Any comments? Can you guys do further power measurements?
-j1: 10.0W +/- 0.5W (0 ... 07.0W with screen disabled)
-j2: 12.7W +/- 0.5W (0 ... 09.6W with screen disabled)
-j3: 13.7W +/- 0.5W (0 ... 10.2W with screen disabled)
-j4: 14.3W +/- 0.5W (0 ... 11.2W with screen disabled)
-j5: 15.0W /- 0.5W (0 ... 11.3W with screen disabled)
-j6: 15.0W /- 0.5W (0. .. 11.4W with screen disabled)
When the screen is turned on, power consumption is quite constant with a variance of +/- 0.5W. It's puzzling that occasionally no power is consumed for a few seconds when the screen is turned off. Maybe the battery is taking over during these short intervals?
The external power supply can provide up to 15W. Utilizing 4 cores, the system requires from time to time almost all that power and while utilizing 5 or 6 core, the system requires all the time all that power and probably occasionally even more. This helps explaining the sudden drops in battery charge from 100% to 91% on systems under load (there are are a few threads here on this board).
I also noticed weird things going on which are barely explainable [the actual timestamps are rough guesses. Numbers for the sake of numbers]:
t=00min. I stress the system with make -j5. Power consumption 15W
t=10min. I continue stressing the system with make -j5: Power consumption goes to 0W.
t=11min. I stop the make -j5. Power consumption remains at 0W.
t=20min. Power consumption goes to 13W.
t=40min. Over the last 20 min, the power consumption went slowly down from 13W eventually reaching 8.4W. 8.4W also the power consumption of a freshly booted system.
I gain the impression that at t=10min, the internal battery may have taken over and then from t=20 to 40, the power supply charged back the internal battery. I did not see any capacity drops on /sys/class/power_supply/cw2015-battery/charge, though. Maybe the charge dropped by less than 0.5% keeping the rounded value of 100?
Let's focus on display off (without load): When the display is off, there is an oscillation of 0W for 2 seconds and 5.4W for two seconds. Do here really main power and battery flip flop charging the Pinebook Pro?
Any comments? Can you guys do further power measurements?