perfetto atrce

Perfetto Trace是一款由Google开源的高性能系统级追踪工具，它专为移动、嵌入式以及云环境设计，用于收集并分析系统性能数据。perfetto trace能够实时捕获各种类型的事件，包括CPU调度、内存分配、网络I/O、图形处理器操作等，并支持详细的上下文信息，方便开发者理解和调试复杂的系统行为。

使用perfetto trace，开发者可以创建定制化的trace配置文件，对特定部分的应用进行跟踪，然后通过perfetto的可视化工具如TraceView或在线分析平台进行查看和分析。它的优势在于高吞吐量、低开销和灵活的数据模型，使得性能分析变得更加精确和高效。

相关问题

perfetto UI

### Perfetto UI Introduction and Usage

Perfetto is an open-source performance tracing platform designed to provide detailed insights into system operations on Android devices as well as other systems that support this tool. The Perfetto user interface (UI), accessible via a web-based application, serves as a powerful visualization tool for analyzing trace data collected by the Perfetto tracer.

The Perfetto UI allows users to load traces either directly from connected devices or through uploading pre-recorded trace files. Once loaded, various aspects of device performance can be explored including CPU scheduling, memory allocation, disk I/O activity such as those obtained using `storaged` command with `-u` option[^1], network traffic, and more.

For interacting effectively within the Perfetto UI:

- **Navigating Traces:** Users may zoom in/out along timelines; pan across different sections of interest.

- **Inspecting Events:** Clickable events display additional metadata about specific occurrences during execution periods.

- **Filtering Data:** Filters help narrow down displayed information based upon event types, processes involved, etc., making it easier to focus analysis efforts where needed most.

An example Python script demonstrating how one might interact programmatically with Perfetto's capabilities could look like below but note actual implementation would depend heavily on intended use case specifics beyond simple interaction patterns shown here:

import subprocess

def start_trace():
    """Starts a perfetto trace session."""
    cmd = ["perfetto", "-c", "config.txt"]
    process = subprocess.Popen(cmd)
    
def stop_and_pull_trace(file_path):
    """Stops current perfetto trace and pulls generated file."""
    pull_cmd = f"adb shell ls /data/misc/perfetto-traces/*.trace > {file_path}"
    subprocess.run(pull_cmd, shell=True)

start_trace()
# ... perform actions you want to profile ...
stop_and_pull_trace("/path/to/local/file.trace")

--related questions--

1. How does one configure custom metrics collection when setting up Perfetto?
2. What are some common pitfalls encountered while interpreting results inside the Perfetto UI?
3. Can multiple instances of Perfetto tracers run simultaneously without interfering each other?
4. Is there any way to automate periodic capturing of performance snapshots over extended durations using Perfetto scripts?

perfetto 分析技巧

Perfetto是一款开源的性能分析工具，主要用于Android系统以及Linux环境下的实时追踪、采样和分析。它提供了一种强大的框架，允许开发者收集关于系统行为的各种详细信息，如内存使用、CPU调度、网络I/O等。以下是几个常用的 Perfetto 分析技巧：

1. **命令行启动**: 使用perfetto trace命令开始一个会话，可以指定需要追踪的进程、时间范围或特定事件。

2. **配置文件**: 创建tracing.xml配置文件，可以自定义采集哪些跟踪点（trace points）和数据模板（data model），这对于复杂场景很有帮助。

3. **实时查看**: 使用perftools如chrome://tracing 或 perfetto-gui来实时分析正在运行的系统，直观地看到性能瓶颈。

4. **分析脚本**: 结合perfetto的Python API或shell脚本，编写定制化的数据分析脚本来深入挖掘数据。

5. **聚合和过滤**: 对大量数据进行预处理，如筛选出特定事件，减少分析时的数据量。

6. **联合分析**: 结合多种数据源（如GPU tracing、Ftrace等），进行跨层的系统级分析。

7. **资源限制**: 当分析大型系统时，了解如何合理设置采样率、堆栈深度等，避免过多开销影响系统性能。