With Google announcing the deprecation of Systrace in favor of Perfetto, Perfetto has essentially replaced Systrace in my daily workflow. Major manufacturers like OPPO and vivo have also transitioned to Perfetto. Many developers new to Android performance optimization find Perfetto’s complex interface and features overwhelming, which is why I’ve decided to re-present my previous Systrace articles using 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.

For those reading, just enjoy the ride!

Currently, the “Knowledge Planet” (ZSXQ) is a paid community. The income mainly goes towards blog server costs and buying cat food for my cat, Douzi. It also serves as my motivation to keep updating the blog. If you find the content helpful, consider joining to support the work! Thank you very much!

The community is named The Performance, a circle for sharing Android performance optimization. I am the host—an Android performance developer at a top-tier smartphone manufacturer in China with years of experience in performance, power consumption analysis, and case studies. This community provides a one-stop-shop for performance knowledge, covering fundamentals, methodologies, tools, and valuable real-world case analyses.

[!NOTE]
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.

These views are my own and carry a subjective perspective. I welcome different viewpoints and hope that through their collision, we can all reach a deeper understanding of the field.

Recently, there was a major buzz around an Android app that exploited a system vulnerability to gain system-level privileges. I wanted to see exactly what an app does once it breaks out of its sandbox and gains that level of control. This led to this article. Due to time constraints, some code wasn’t examined in detail. Interested readers can study it themselves and discuss further. The corresponding articles and code links are below:

1. Deep Blue Insight: 2022’s Most “Unforgivable” Vulnerability
2. XXX apk Embedded Privilege Escalation Code and Dynamic Dex Delivery Analysis
3. History of Android Deserialization Vulnerability Attacks and Defenses

Regarding how this app obtained system permissions, History of Android Deserialization Vulnerability Attacks and Defenses explains it clearly, so I won’t elaborate further. I’m not a security expert, but I recommend reading this article multiple times.

A while ago, a certain App became very popular because it exploited Android system vulnerabilities to gain system permissions and did a lot of things. I wanted to see what these Apps did after gaining system permissions by exploiting system vulnerabilities, hence this article. Due to hasty preparation, some Code was not looked at carefully. Interested students can research it themselves and discuss more. The corresponding articles and Code links are below:

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

Regarding how this App obtained these system permissions, History of Android Deserialization Vulnerability Attack and Defense explains it very clearly, so I won’t repeat it here. I am not a security expert either, but I suggest everyone read this article a few times.

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!

While we expected to wrap up in an hour, we ended up chatting for over two and a half hours—our introductions alone took an hour! Our community spans the entire Android ecosystem: from App-tier experts to System-level gurus at major smartphone manufacturers, silicon companies, and EV startups. Each introduction naturally evolved into deep dives into industry trends and company-specific insights.

We plan to hold these regularly with clearer themes and more guests. To protect the privacy of our members, we did not record the session. The following text is a reconstructed summary of our discussion.

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 are major performance inhibitors and are often difficult to diagnose without a systematic approach.

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 , 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

If you Google search “Android optimization tools,” you’ll find many related contents. Their problem is that content is highly repetitive, or they directly explain usage methods. They rarely introduce overall architecture, which can easily make you form the erroneous cognition of “one tool handles everything.” Based on my team’s years of experience, in the performance profiling field, such a silver bullet-level tool does not exist. Tools are evolving, old problems will appear in new forms. If you don’t master the core logic, you’ll always float on the surface of technology.

This article will systematically organize observable technologies in performance profiling, covering three parts of content: data types, capture methods, and analysis methods. After that, we’ll introduce Google’s “Big Three” analysis tools. The goal is to let you understand immutable theoretical knowledge and corresponding tools available in the Android environment, so you can take fewer detours and directly reuse predecessors’ experience.

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

A Google search for “Android optimization tools” yields an abundance of related content. The issue with these results is that they either contain highly repetitive content or directly explain usage methods. Rarely do they introduce a holistic architecture, inadvertently instilling a misguided belief of “one tool fixes all”. Drawing from the extensive experience of my team, I can assert that in the realm of performance analysis, no such magic bullet tool exists. Tools evolve, old problems re-emerge in new forms, and without mastering core logic, one remains on the technological surface.

This article first systematically untangles the observability technology in performance analysis, encompassing data types, capture methods, and analysis techniques. Subsequently, we introduce the “big three” analysis tools provided by Google. The aim is to impart immutable theoretical knowledge and corresponding tools available in the Android environment to the reader. This wealth of information can facilitate a more direct application of predecessors’ experiences, circumventing unnecessary detours.

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 boring period of working from home), 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. 2022 needs to be a year of deep cultivation. 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 has been officially released, and the source code is now available on the AOSP website. This article will guide you through the process of downloading and compiling the latest Android 12 code.

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: You can compile a userdebug version, which allows for root and remount access. This is invaluable for debugging both the system and apps, as it reveals information hidden in standard user builds—useful for competitive analysis and behavioral studies.
3. Deep Learning: It facilitates a deeper understanding of Android source code by allowing you to enable system-level debug logs, add your own logs, or even modify system workflows.