AIW is an Android systems and performance ebook you can read online, download as an EPUB, and check against source code. Its five parts and 26 chapters connect application code with Framework, Native and Kernel mechanisms, including how to investigate them with Perfetto and other tools.

Bring a slow startup, janky scroll, ANR or battery problem to the book, or follow the contents to build a broader understanding. Both the web edition and the ebook are free to read:

• Read online: wiki.androidperformance.com
• Source text and full contents: GitHub
• Download EPUB: GitHub Releases

This introduction reflects the content available in November 2026. The book remains in alpha. Android 17 / API 37 is the highest version covered by its definitive claims; the complete English edition is planned after v1.0. The book itself is currently in Chinese.

In his book , Paul Graham states: “The execution efficiency gap between different programming languages is becoming increasingly large, so profilers are becoming more important. Currently, performance profiling is not receiving enough attention. Many people still believe that the key to improving program running speed is developing compilers that can generate faster code. The gap between code efficiency and machine performance is continuously increasing, and we will increasingly clearly see that the key to improving application software running speed is having a good performance profiler to guide program development.”

By Paul Graham — Hackers and Painters

Search for “Android optimization tools” and you’ll find plenty of articles. Many repeat the same material or go straight to instructions without explaining how the tools fit together. It is easy to come away thinking one tool can solve everything. Our team’s experience says otherwise: there is no silver bullet. Tools change, and familiar problems return in new forms. You still need to understand what is happening underneath.

We’ll start with the data we collect, how we collect it, and how we analyze it. Then we’ll look at Google’s traditional “big three” performance tools. We want you to understand the measurements as well as the tools, and save yourself some of the detours others have already taken.

In his book Hackers & Painters, Paul Graham asserted, “The disparity in the efficiency of languages is becoming more pronounced, hence the rising importance of profilers. Currently, performance analysis isn’t given the attention it deserves. Many still seem to hold onto the belief that the key to accelerating program execution lies in developing compilers that generate faster code. As the gap between code efficiency and machine performance widens, it will become increasingly apparent that enhancing the execution speed of application software hinges on having a good profiler to guide program development.” by Paul Graham, Hackers & Painters

Search for “Android optimization tools” and you’ll find plenty of articles. Many repeat the same material or go straight to instructions without explaining how the tools fit together. It is easy to come away thinking one tool can solve everything. Our team’s experience says otherwise: there is no silver bullet. Tools change, and familiar problems return in new forms. You still need to understand what is happening underneath.

We’ll start with the data we collect, how we collect it, and how we analyze it. Then we’ll look at Google’s traditional “big three” performance tools. We want you to understand the measurements as well as the tools, and save yourself some of the detours others have already taken.

This article records a 2019 issue: animation work continued after the app’s UI was no longer visible. However, some apps continue to run “zombie animations”—animations that are completely invisible to the user yet consume precious CPU cycles and battery. When users discover this, the result is often a manual kill, an OS-level background restriction, or an outright uninstallation.

This issue can be easy to miss. In the original investigation, I used Systrace after opening apps and returning home, capturing traces while swiping between launcher pages. Some departed apps still fired callbacks. A reproduction should record versions, operations, and visibility; opening many apps is not itself a diagnostic requirement or proof.

Here, “zombie animations” means updates that continue when their UI is invisible and the feature no longer needs them. Many paths can schedule animation work through Choreographer. Investigate the actual stack, playback state, and library version. A live process is not necessarily free to consume CPU indefinitely; modern systems can freeze eligible cached processes.

Whether you are an Android App developer or a System developer, having a foundational understanding of the Android system is extremely beneficial. I recently set up a development environment at home and decided to share the process for anyone interested. The general steps involved are as follows:...