This is the first article in the Perfetto series. It mainly provides a brief introduction to the Perfetto tool, including its history, development, and what Perfetto can do.

Android documentation labels Systrace a legacy tool and recommends Perfetto on Android 10+. By the time I wrote this article, Perfetto had largely replaced Systrace in my daily work, and the OPPO and vivo teams I encountered were also migrating. Newcomers facing its complex interface asked me to revisit the Systrace articles using Perfetto.

Technical review: 2026-10-14. The original article and screenshots date from 2024. The updates below distinguish Android 10/11/12 data-source requirements and Perfetto v48.0/v49.0 UI changes from that earlier experience. Available data still depends on the device, recording configuration, and tool version.

Perfetto has largely replaced the old Systrace workflow in my daily work. Android recommends Perfetto for Android 10 and later and describes the Systrace command-line tool as legacy. Developers new to Android performance analysis often find Perfetto’s interface and features complex, so this series revisits the subjects of my Systrace articles through Perfetto.

I’m taking the easy way out this year and using a template to look back at the past year through several lenses: Health/Fitness, Work/Career, Friendship/Social, Personal Life/Family, Learning/Knowledge Management, Travel/Culture, Interests/Creativity, Emotions/Mental State, and Finances.

This post is more of a personal record for 2023 than a formal summary, and my writing isn’t anything special. But as I’ve realized, if you don’t record things, they slowly fade away. I hope that whenever I look back at this post, I’ll remember 2023 as a vibrant year—filled with unforgettable moments, low points, visits from distant friends, and journeys through mountains and rivers. I also want to remember the things I did poorly so I can do better next time, and to remind myself to fight the laziness that often prevents me from following through on what I know is right.

Feel free to read along and have a laugh at my expense.

This article was originally written by Yingyun for my Knowledge Planet. Since the Planet has closed, I am publishing this series on OS performance design here.

Yingyun is a veteran performance optimization expert with deep insights into system-level tuning, having worked at several major smartphone manufacturers. He is currently active in our community. If you have any questions or feedback, feel free to join our WeChat group.

1. The Genesis

This starts a new series exploring the various considerations in OS architectural design. In reality, these principles apply to the design of any large-scale software.

My knowledge and experience have limits, and these views are subjective. There will be gaps. I would like to hear other views and see what I have missed.

In 2023, public research described vulnerability exploitation code and dynamically delivered DEX files associated with an Android app. I wanted to see which system capabilities this code attempted to use. I put the original article together in a hurry and did not examine all the code closely. The walkthrough remains here, with corrections based on the screenshots and AOSP source. The original references follow:

1. Deep Blue Insight: The Most “Unpardonable” Vulnerabilities of 2022
2. XXX apk embedded privilege escalation code and dynamic delivery dex analysis
3. History of Android Deserialization Vulnerability Attack and Defense

Security is not my specialty. For background, see History of Android Deserialization Vulnerability Attack and Defense. This article does not reproduce the exploit chain or treat an API call as proof of root access.

On Friday, March 25, 2022, at 9 PM, “The Performance” Knowledge Planet held its first online “Tea Talk.” We were joined by 3 planet hosts, 5 guest experts, and over 50 members. Thank you all for coming!

We had no set topic and expected to finish in an hour. We ended up talking for two and a half hours; introductions alone took an hour! We had talked plenty in the group and on Knowledge Planet, but this was our first voice chat together. People worked across the Android ecosystem, from app companies and phone manufacturers to chip companies and EV startups. Someone would mention their work, someone else would ask a question, and off we went.

At the time, we planned to hold more sessions with clearer themes and more guests, on topics beyond technology too. We did not record this session to protect participants’ privacy. The notes below reconstruct part of the conversation without including private details.

This is the third article in the “Systrace Thread CPU State Analysis Tips” series. It focuses on the Sleep and Uninterruptible Sleep states in Systrace—their causes, troubleshooting, and optimization. These states often represent normal waiting; investigate their conditions and dependencies when they delay a critical path.

The goal of this series is to use Systrace to view the Android system from a different perspective and to learn the Framework through visualization. While reading Framework source code can be difficult to remember, seeing the flow in Systrace can lead to deeper understanding. You can find the complete Systrace Basics and Action Series here.

This is the second article in the “Systrace Thread CPU State Analysis Tips” series. It analyzes the causes of the “Running” state in Systrace and provides optimization strategies for when Running segments are excessively long.

The goal of this series is to use Systrace to view the Android system from a different perspective and to learn the Framework through visualization. While reading Framework source code can be difficult to remember, seeing the flow in Systrace can lead to deeper understanding. You can find the complete Systrace Basics and Action Series here.

This is the first article in the “Systrace Thread CPU State Analysis Tips” series. It analyzes the causes of the “Runnable” state in Systrace and provides optimization strategies for when Runnable segments are excessively long.

The goal of this series is to use Systrace to view the Android system from a different perspective and to learn the Framework through visualization. While reading Framework source code can be difficult to remember, seeing the flow in Systrace can lead to deeper understanding. You can find the complete Systrace Basics and Action Series here.

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.

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.

2021 has passed. Taking advantage of the New Year holiday, I’d like to look back at the year. This will be a casual review—writing whatever comes to mind. 2021 for me was marked by becoming a father, changing jobs (including a long, boring spell at home in between), and making new friends. Overall, it was a pretty good year.

However, in terms of personal growth, I feel like I might have stagnated or even regressed, which is a bit alarming. Learning is like rowing upstream; if you don’t move forward, you fall back. In 2022, I need to spend more time working through things properly. I hope to progress together with everyone reading this.

I’ve also tallied some data related to my technical sharing, shared my income from these platforms, and listed some hardware and software I recommend. Feel free to take a look.

Recently, I read a new book: Building Smooth Android Apps (JD link: https://item.jd.com/10035215362170.html). I bought it because of the title, and after reading it, I felt it was necessary to write an article so that colleagues who haven’t bought it yet can understand what it’s about.

My personal suggestion is: if you are an experienced developer, I don’t recommend buying it. This book doesn’t go into much depth on principles and doesn’t offer a comprehensive overview of Android smoothness. If you are a beginner, it’s decent for broadening your horizons and identifying gaps in your knowledge, but it’s still a bit lacking for a deep understanding of Android smoothness.

I say this because the book doesn’t focus much on performance or smoothness. It lacks deep theoretical parts. Instead, a large portion is dedicated to static code analysis, using Android Studio Profiler, App architecture, app stay-alive techniques, network performance optimization, APK size optimization, app power consumption, etc. These topics are covered briefly and at a shallow level.

Android 12 source was released in 2021. My test phone at the time was a Pixel 3 XL. This article keeps that hands-on record and pins the release-build example to android-12.0.0_r3. Verify version mappings in the AOSP tags/build numbers table.

Compiling the code locally offers several advantages:

1. Direct Debugging: You can flash the build onto a physical device for local debugging and import the code into Android Studio.
2. Userdebug Builds: These provide additional debugging capabilities. adb root/remount still depends on adbd, AVB/verity, partition layout, and build configuration. A userdebug build does not make every directory writable or replace an app’s own debugging permissions.
3. Studying the System: You can enable more system debug logs, add your own, and change the code to see how it works.

Jank, slow response, and ANRs can share causes or occur together, but they are not three severity levels of the same problem. When a user says an app feels slow, first distinguish uneven animation, a long delay after an action, and a system-detected failure to respond.

Animation and scrolling stutter is usually called jank. Long startup, screen wake-up, or navigation delays are slow response / high latency. An ANR depends on a specific system timeout condition. Frame-drop rate, startup duration, and ANR rate measure different things.

This is the third article in the Responsiveness series, focusing on extended knowledge when using Systrace to analyze app responsiveness, including startup speed testing, log interpretation, state analysis, and third-party startup libraries.