DISCLAIMER: This is not an official Google product.
Post about WALT on Android Developers Blog
WALT is designed to measure the latency of physical sensors and outputs on phones and computers. It can currently perform the following measurements:
- Tap latency - time from the moment a finger-like probe touches down (or up) on the screen until the kernel timestamps an ACTION_DOWN (or ACTION_UP) event. This physical contact with the screen is timed using an accelerometer mounted on the probe - details
- Drag latency (scroll) - details
- Screen draw latency - using a photodiode that detects whether the screen is black or white.
- Audio input / output latencies. Input latency will be usually referred as microphone latency.
- Hardware build instructions can be found in this repository under hardware/
- Clock syncrhonization details are described here
- The Android device and Teensy clocks have a tendency to diverge due to differing clock frequencies. This means they will go out of sync after approximately 5 minutes. The workaround is to use the app to re-sync the clocks.
- Python code used to communicate with WALT from ChromeOS can be found here