Capture a system trace on the command line

The systrace command invokes the Systrace tool, which allows you to collect and inspect timing information across all processes running on your device at the system level.

This document explains how to generate Systrace reports from the command line. On devices running Android 9 (API level 28) or higher, you can also generate Systrace reports using the System Tracing system app.

In order to run systrace, complete the following steps:

  1. From Android Studio, download and install the latest Android SDK Tools.
  2. Install Python and include it in your workstation's PATH environment variable.
  3. Add android-sdk/platform-tools/ to your PATH environment variable. This directory contains the Android Debug Bridge binary (adb), which is called by the systrace program.
  4. Connect a device running Android 4.3 (API level 18) or higher to your development system using a USB debugging connection.

The systrace command is provided in the Android SDK Tools package and is located in android-sdk/platform-tools/systrace/.

Syntax

To generate the HTML report for app, you need to run systrace from the command line using the following syntax:

python systrace.py [options] [categories]

For example, the following command calls systrace to record device activity and generate a HTML report named mynewtrace.html. This list of categories is a reasonable default list for most devices.

$ python systrace.py -o mynewtrace.html sched freq idle am wm gfx view \
    binder_driver hal dalvik camera input res memory

Tip: If you want to see the names of tasks in the trace output, you must include the sched category in your command parameters.

To view the list of categories that your connected device supports, run the following command:

$ python systrace.py --list-categories

If you don't specify any categories or options, systrace generates a report that includes all available categories and uses default settings. The categories available depend on the connected device you're using.

Global options

Global options Description
-h | --help Show the help message.
-l | --list-categories Lists the tracing categories available to your connected device.

Commands and command options

Commands and options Description
-o file Write the HTML trace report to the specified file. If you don't specify this option, systrace saves your report to the same directory as systrace.py and names it trace.html.
-t N | --time=N Trace device activity for N seconds. If you don't specify this option, systrace prompts you to end the trace by pressing the Enter key from the command line.
-b N | --buf-size=N Use a trace buffer size of N kilobytes. This option lets you limit the total size of the data collected during a trace.
-k functions
| --ktrace=functions		 Trace the activity of specific kernel functions, specified in a comma-separated list.
-a app-name
| --app=app-name		 Enable tracing for apps, specified as a comma-separated list of process names. The apps must contain tracing instrumentation calls from the Trace class. You should specify this option whenever you profile your app—many libraries, such as RecyclerView, include tracing instrumentation calls that provide useful information when you enable app-level tracing. For more information, see Define custom events.

To trace all apps on a device running Android 9 (API level 28) or higher, pass the wildcard character "*", including the quotation marks.

--from-file=file-path Create an interactive HTML report from a file, such as TXT files that include raw trace data, instead of running a live trace.
-e device-serial
| --serial=device-serial		 Conduct the trace on a specific connected device, identified by its device serial number.
categories Include tracing information for the system processes you specify, such as gfx for system processes that render graphics. You can run systrace with the -l command to see a list of services available to your connected device.