Quickstart: Record traces on Android

perfetto allows you to collect system-wide performance traces from Android devices from a variety of data sources (kernel scheduler via ftrace, userspace instrumentation via atrace and all other data sources listed in this site).

Starting the tracing services

Due to Perfetto's service-based architecture , the traced and traced_probes services need to be running to record traces.

These services are shipped on Android system images by default since Android 9 (Pie) but are not always enabled by default. On Android 9 (P) and 10 (Q) those services are enabled by default only on Pixel phones and must be manually enabled on other phones. Since Android 11 (R), perfetto services are enabled by default on most devices.

To enable perfetto services run:

# Will start both traced and traced_probes. adb shell setprop persist.traced.enable 1

Recording a trace

You can collect a trace in the following ways:

Perfetto UI

Navigate to ui.perfetto.dev and select Record new trace.

From this page, select and turn on the data sources you want to include in the trace. More detail about the different data sources can be found in the Data sources section of the docs.

Record page of the Perfetto UI

If you are unsure, start by turning on Scheduling details under the CPU tab.

Ensure your device is connected and select Add ADB device. Once your device has successfully paired (you may need to allow USB debugging on the device), select the Start Recording button.

Allow time for the trace to be collected (10s by default) and then you should see the trace appear.

Perfetto UI with a trace loaded

Your trace may look different depending on which data sources you enabled.

Perfetto cmdline

Short syntax

If you are already familiar with systrace or atrace, there is an equivalent syntax with perfetto:

adb shell perfetto -o /data/misc/perfetto-traces/trace -t 20s sched freq idle am wm gfx view

Full trace config

The short syntax allows to enable only a subset of the data sources; for full control of the trace config, pass the full trace config in input.

See the Trace configuration page and the examples in each data source doc page for detailed instructions about how to configure all the various knobs of Perfetto.

If you are running on a Mac or Linux host, or are using a bash-based terminal on Windows, you can use the following:

WARNING: The below command does not work on Android P because the --txt option was introduced in Q. The binary protobuf format should be used instead; the details of this can be found on the Trace configuration page.

adb shell perfetto \ -c - --txt \ -o /data/misc/perfetto-traces/trace \ <<EOF duration_ms: 10000 buffers: { size_kb: 8960 fill_policy: DISCARD } buffers: { size_kb: 1280 fill_policy: DISCARD } data_sources: { config { name: "linux.ftrace" ftrace_config { ftrace_events: "sched/sched_switch" ftrace_events: "power/suspend_resume" ftrace_events: "sched/sched_process_exit" ftrace_events: "sched/sched_process_free" ftrace_events: "task/task_newtask" ftrace_events: "task/task_rename" ftrace_events: "ftrace/print" atrace_categories: "gfx" atrace_categories: "view" atrace_categories: "webview" atrace_categories: "camera" atrace_categories: "dalvik" atrace_categories: "power" } } } data_sources: { config { name: "linux.process_stats" target_buffer: 1 process_stats_config { scan_all_processes_on_start: true } } } EOF

In all other cases, first push the trace config file and then invoke perfetto:

adb push config.txt /data/local/tmp/trace_config.txt adb shell 'perfetto --txt -c - -o /data/misc/perfetto-traces/trace < /data/local/tmp/trace_config.txt'

NOTE: because of strict SELinux rules, on versions of older than Android 11 (R) passing directly the file path as -c /data/local/tmp/config might fail, hence the -c - + stdin piping above.

Pull the file using adb pull /data/misc/perfetto-traces/trace ~/trace.pftrace and upload to the Perfetto UI.

The full reference for the perfetto cmdline interface can be found here.

On-device System Tracing app

Since Android 9 (P) it's possible to collect a trace directly from the device using the System Tracing app, from Developer Settings.

See https://developer.android.com/topic/performance/tracing/on-device for instructions.