This article introduces Choreographer, a class that App developers may not frequently encounter but is critically important in the Android Framework rendering pipeline. We will cover the background of its introduction, a brief overview, partial source code analysis, its interaction with MessageQueue, its application in APM (Application Performance Monitoring), and some optimization ideas for Choreographer by mobile phone manufacturers.

The introduction of Choreographer is mainly to cooperate with Vsync to provide a stable Message processing timing for upper-layer application rendering. When the Vsync signal arrives, the system controls the timing of each frame’s drawing operation by adjusting the Vsync signal cycle. Currently, the screen refresh rate of mainstream mobile phones has reached 120Hz, which means refreshing once every 8.3ms. The system adjusts the Vsync cycle accordingly to match the screen refresh frequency. When each Vsync cycle arrives, the Vsync signal wakes up the Choreographer to execute the application’s drawing operation. This is the main purpose of introducing Choreographer. Understanding Choreographer can also help application developers deeply understand the operating principle of each frame, and at the same time deepen their understanding of core components such as Message, Handler, Looper, MessageQueue, Input, Animation, Measure, Layout, and Draw. Many APM (Application Performance Monitoring) tools also utilize the combination mechanisms of Choreographer (via FrameCallback), FrameMetrics/gfxinfo framestats (internally backed by FrameInfo), MessageQueue (via IdleHandler), and Looper (via custom MessageLogging) for performance monitoring. After deeply understanding these mechanisms, developers can conduct performance optimization more specifically and form systematic optimization ideas.

This is the fourth article in the Perfetto series, explaining how to use trace_processor_shell to open large files exceeding 2GB locally. In actual problem analysis, we often encounter very large Trace files (greater than 2GB) that cannot be opened by directly dragging them into ui.perfetto.dev due to browser memory limitations. In this case, we need to use the trace_processor_shell tool provided by the official to open large files locally.

With Google announcing the deprecation of the Systrace tool and the release of Perfetto, Perfetto has basically replaced Systrace in my daily work. At the same time, major manufacturers like OPPO and Vivo have also switched from Systrace to Perfetto. Many friends who are new to Android performance optimization feel a headache when facing the dazzling interface and complex functions of Perfetto. They hope that I can present those previous Systrace articles using Perfetto.

This is the third article in the Android App ANR series, focusing on real-world ANR cases. The series includes:

1. Android App ANR Series 1: Understanding Android ANR Design Philosophy
2. Android App ANR Series 2: ANR Analysis Workflow and Key Logs
3. Android App ANR Series 3: ANR Case Studies

This is the second article in the Android App ANR series, focusing on ANR analysis methodology and key logs. The series includes:

1. Android App ANR Series 1: Understanding Android ANR Design Philosophy
2. Android App ANR Series 2: ANR Analysis Methodology and Key Logs
3. Android App ANR Series 3: ANR Case Studies

This is the first article in the Android App ANR series, mainly analyzing the design philosophy of Android ANR from a system perspective. The series directory is as follows:

1. Android App ANR Series 1: Understanding Android ANR Design Philosophy
2. Android App ANR Series 2: ANR Analysis Routines and Key Log Introduction
3. Android App ANR Series 3: ANR Case Sharing

This is the third article in the Perfetto series. The first two articles introduced what Perfetto is and how to capture Perfetto Trace. This article simply introduces how to look at the complex Perfetto information after opening Perfetto Trace on the web side.

With Google announcing the deprecation of the Systrace tool and the release of Perfetto, Perfetto has basically replaced Systrace in my daily work. At the same time, major manufacturers like OPPO and Vivo have also switched from Systrace to Perfetto. Many friends who are new to Android performance optimization feel a headache when facing the dazzling interface and complex functions of Perfetto. They hope that I can present those previous Systrace articles using Perfetto.

The previous article Android Perfetto Series 1: Introduction to Perfetto introduced what Perfetto is. This article provides a brief introduction to Perfetto capture.

With Google announcing the deprecation of the Systrace tool and the release of Perfetto, Perfetto has basically replaced Systrace in my daily work. At the same time, major manufacturers like OPPO and Vivo have also switched from Systrace to Perfetto. Many friends who are new to Android performance optimization feel a headache when facing the dazzling interface and complex functions of Perfetto. They hope that I can present those previous Systrace articles using Perfetto.

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.

With Google announcing the deprecation of the Systrace tool and the release of Perfetto, Perfetto has basically replaced Systrace in my daily work. At the same time, major manufacturers like OPPO and Vivo have also switched from Systrace to Perfetto. Many friends who are new to Android performance optimization feel a headache when facing the dazzling interface and complex functions of Perfetto. They hope that I can present those previous Systrace articles using Perfetto.

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.

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.