Android Performance

Technical update — 2026-10-13: Historical Systrace screenshots are retained, including cases added after the original 2019 article. Colors and shortcuts refer to the legacy UI. Linux state semantics are checked against v6.6 documentation; the modern UI reference is Perfetto v58.3 (11fbaed83). Inaccurate Self Time, wakeup and scheduling-state annotations in the images are corrected in the adjacent text. These are not new device measurements.

This is the second article in the Systrace series, primarily explaining the prerequisites for analyzing Systrace. With these prerequisites, analyzing Systrace will be more effective, allowing you to identify issues faster and more efficiently.

This article introduces how to view thread states in Systrace, how to analyze thread wakeup information, how to interpret data in the information panel, and common shortcuts. By studying this article, you will gain an understanding of process and thread-related information and know how to extract key information from complex Systrace traces.

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.

Technical update — 2026-10-13: First published in 2019, this article retains Systrace HTML and script workflows as historical references. Modern capture examples start from Android 11 / API 30+, with separate version requirements for app tracing APIs, permissions and data sources. Device-side atrace, host-side systrace.py and perfetto are different tools; their options are not interchangeable.

This is the first article in the Systrace series, primarily providing a brief introduction to Systrace, its basic usage, how to interpret Systrace traces, and how to analyze phenomena in Systrace in conjunction with other tools.

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.

Technical update — 2026-10-13: First published in 2019, this article uses 60 Hz devices to explain frame pacing. 60 FPS is not a fixed standard for every Android device. The universal 16.67 ms budget, mismatched-rate examples and power claims are corrected below, with updated tools available from Android 11 / API 30 and Android 12 / API 31.

This is the third article in the Systrace series, explaining why 60 FPS is constantly emphasized. Here, FPS describes the app’s content frame rate, while Hz describes display refresh rate; they measure different things. For further context, refer to: A New Smooth Experience: A Talk on 90Hz.

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.

This article separates frame rate from refresh rate, then discusses pacing, power and response latency. On 90 Hz and 120 Hz devices, content updates still need to work with display timing, but 60 FPS and 16.67 ms are no longer universal targets.

Technical update — 2026-10-13: This page is dated 2019 and retains update records from earlier tutorials. The old Systrace tooling workflow is obsolete. Read historical screenshots, source code and experiments against the Android versions stated in each article; they do not describe every current implementation. Start with the Perfetto series below for current capture and analysis workflows.

As Systrace and Android changed, my earlier tutorials started to show their age. I had also learned to read more from a trace, which helped me solve performance problems. I wanted to write those things down and get better at explaining what I had learned. If the notes helped someone else too, all the better.

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.

Version note — reviewed October 13, 2026: This article was written in 2019. Its device opinions, 90 Hz “sweet spot,” and buying outlook are historical, not current purchase advice. The technical explanations are corrected below, with Android 11/API 30 and Android 15 QPR1 updates. The old tr...

I’ve been following the Sharp Tools Community Program for a long time. I’ve learned a lot from everyone’s sharing. As stated in the beginning: “Both tools and inspiration are sharp tools. When tools and inspiration from different fields and creators collide, more possibilities arise.“ Below are m...

I saw the Liqi Community Project a long time ago. I learned a lot from everyone’s sharing. As stated in the beginning: “Tools and inspiration are both Liqi. When tools and inspiration from different fields collide with each other, more possibilities will emerge.“ Below are my simple answers to th...

Phenomenon Version note — reviewed October 13, 2026: This is a historical 2019 case without the complete trace, ROM build, or app versions. The old call chain is checked against AOSP android-9.0.0_r1 as a reference, not an identification of the original ROM. An android-16.0.0_r1 comparison is add...

At the beginning of 2018, I wrote 2017 Best Items Recommendations. Recently, some people asked if I’d do one for 2018. Although 2018 was a tough year, there were still some great things worth recommending to everyone.

Just like in 2017, I’ll share things that I found helpful for work or life. The recommendations include apps, hardware, books, blogs, and columns. I hope they provide value to you in 2019.

Historical recommendations (reviewed October 2026): This is a record of my 2018 experience. Book lists, ratings, prices, course posters, and buying recommendations belong to that period. Updated platform support and membership limits are noted below; old QR codes are not current enrollment links.

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:...

Reposted from: Baidu Family, based on Lu Qi’s internal sharing at Baidu in July 2017. It is highly worth learning and pondering for technical personnel. Historical reprint (reviewed October 2026): The speech text and personal appreciation below are preserved. Roles, schedules, and patent count...

This is the eighth post in the reading notes series for The Programmer’s Apprenticeship: From Good to Great. The author, Jeff Atwood, is one of the founders of Stack Overflow. His articles cover a wide range of topics. He is a seasoned programmer, manager, and entrepreneur. This book discusses ma...

This is the seventh post in the reading notes series for How to Stop Sucking and Be Awesome Instead, published in Chinese as 《程序员的修炼——从优秀到卓越》 (the series title here is The Programmer’s Apprenticeship). The author, Jeff Atwood, is one of the founders of Stack Overflow. His articles cover a wide ra...

This is the sixth post in the reading notes series for How to Stop Sucking and Be Awesome Instead, published in Chinese as 《程序员的修炼——从优秀到卓越》 (the series title here is The Programmer’s Apprenticeship). The author, Jeff Atwood, is one of the founders of Stack Overflow. His articles cover a wide rang...