Technical update — 2026-10-13: The historical screenshots and code are retained. Code excerpts were checked against AOSP android-10.0.0_r1; modern differences use android-16.0.0_r1 as an example. These tags do not identify the screenshot devices: the original traces, ROMs and build details were not supplied. The descriptions of animation ownership, StartingWindow and thread interactions are corrected below.

This is the fourth article in the Systrace series, primarily providing a brief introduction to SystemServer. It covers several important threads within SystemServer. Since Input and Binder are particularly critical, they are discussed separately and won’t be covered in detail here.

The purpose of this series is to view the overall operation of the Android system from a different perspective using Systrace, while also providing an alternative angle for learning the Framework. Perhaps you’ve read many articles about the Framework but can never remember the code, or you’re unclear about the execution flow. Maybe from Systrace’s graphical perspective, you can gain a deeper understanding.