How do you measure what a chip is doing?

Chips report their own speed, power, temperature and sleep time. Tools record these numbers while the chip runs a test, busy or idle.

1. The chip's dashboard
Telemetry is data a chip reports about itself, like a car's dashboard. Tools on Windows and Linux show its clock speed (how fast it works), voltage, power, temperature and time asleep (residency).
2. Heavy work on purpose
A workload is a program run on purpose during a test. Heavy ones, like a drive up a hill, keep one part busy, such as the main cores (the main workers).
3. Light work on purpose
Other workloads are light on purpose, like playing a video or leaving the desktop alone. They show how well the chip rests, like a car waiting at a red light.
4. Watch it over time
One glance at a dashboard tells little about a whole drive. A log, a list of readings taken over time, shows clock speed and power rise and fall with the workload.
5. Check from outside
The chip's own power reading is often an estimate, so some labs also measure power from outside. A precision meter on a power rail, one of the board's power lines, checks it, like a mechanic checking a gauge.

Words to know

Telemetry: Readings a chip reports about itself while it runs.
Residency: The share of time a part of the chip spends in one state, such as asleep, often shown in percent.
Workload: A program run on purpose during a test, from heavy work to almost nothing.
Log: A list of readings taken again and again over time.
Power rail: A power line on the board that feeds one or more parts of the chip, such as the main cores.

Most test results are telemetry logs recorded while a workload runs. Testers compare them with how the chip should behave.

Why record a log instead of one reading?Think first, then tap to see the answer.

A log shows how clock speed and power change as the workload starts and stops.