Device performance

CPU, memory, thermal and battery readings taken alongside the network metrics, on the same one-second tick. They exist to separate network problems from phone problems: thermal throttling and battery-saver modes are classic causes of a “slow network” that has nothing wrong with the network at all.

Metric	What it means	Unit	How to read	Source	Learn more
App CPU `perf.cpu_app`	CPU used by the YANL app process.	%	Lower is better	Android	Reference
Battery saver `perf.power_save`	Whether battery saver is switched on. Battery saver throttles background work, which can slow transfers and delay anything the app is not actively doing.	—	—	Android	Reference
Current `perf.battery_current`	Battery current draw in milliamps.	mA	Lower is better	Android	Reference
Doze `perf.doze_state`	Whether Android has put the device into deep doze, which suspends background network access. Only deep doze is visible to apps; light doze is not exposed below Android 13, so 0 does not prove the system is leaving traffic alone.	—	—	Android	Reference
Memory `perf.mem_percent`	Device memory utilisation percentage.	%	Lower is better	Android	Reference
Power `perf.battery_power`	Instantaneous power draw while testing.	mW	Lower is better	Android	Reference
Relative drain `perf.battery_drain_norm`	How fast the battery is draining right now compared with the typical rate for this session. Around 1 is normal for the session; higher means this moment is costing more than usual.	×	Lower is better	YANL	—
Screen `perf.screen_state`	Whether the display was on at each sample. Useful for telling apart what the phone does while you are using it and what it does in your pocket.	—	—	Android	Reference
Thermal `perf.thermal`	Device thermal status, useful when testing under load.	°C	Lower is better	Android	Reference