PERFETTO(1)

NAME
perfetto - capture traces

DESCRIPTION
This section describes how to use the perfetto commandline binary to capture traces. Examples are given in terms of an Android device connected over ADB.

perfetto has two modes for configuring the tracing session (i.e. what and how to collect):

lightweight mode
    all config options are supplied as commandline flags, but the available data sources are restricted to ftrace and atrace. This mode is similar to systrace (https://developer.android.com/topic/performance/tracing/command-line) .

normal mode
    the configuration is specified in a protocol buffer. This allows for full customisation of collected traces.

GENERAL OPTIONS
The following table lists the available options when using perfetto in either mode.

-d, --background
    Perfetto immediately exits the command-line interface and continues recording your trace in background.

-D, --background-wait
    Like --background, but waits (up to 30s) for all data sources to be started before exiting.

--notify-fd FD
    Like --background-wait, but instead of daemonizing and waiting before exiting, writes one status byte and closes the given file descriptor. Writes 0 on success, non-zero on timeout/error. Not supported on Windows.

-o, --out OUT_FILE
    Specifies the desired path to the output trace file, or - for stdout. perfetto writes the output to the file described in the flags above. The output format compiles with the format defined in AOSP trace.proto.

--no-clobber
    Do not overwrite an existing output file.

--clone TSID
    Creates a read-only clone of an existing tracing session identified by session id (see --query).

--clone-by-name NAME
    Creates a read-only clone of an existing tracing session identified by unique_session_name.

--clone-for-bugreport
    Can only be used with --clone or --clone-by-name. Disables trace_filter on the cloned session.

--add-note key[=value]
    Adds a user note to the trace config. If =value is omitted, value is an empty string.

--version
    Prints the perfetto version string and exits.

--dropbox TAG
    Deprecated. Uploads your trace via the https://developer.android.com/reference/android/os/DropBoxManager.html DropBoxManager API using the tag you specify. Android only. Use --upload instead.

--upload
    Uploads trace output to Android framework reporting paths configured in TraceConfig (android_report_config). Android only.

--alert-id ID
    Statsd metadata. ID of the alert that triggered this trace.

--config-id ID
    Statsd metadata. ID of the triggering config.

--config-uid UID
    Statsd metadata. UID of app which registered the triggering config.

--subscription-id ID
    Statsd metadata. ID of the subscription that triggered this trace.

--save-for-bugreport
    If a trace with bugreport_score > 0 is running, saves it into a file and outputs the path when done.

--save-all-for-bugreport
    Clones all eligible bugreport sessions and saves them into bugreport output files.

--no-guardrails
    Disables protections against excessive resource usage when using --upload (testing only).

--reset-guardrails
    Compatibility option. Guardrails no longer exist in perfetto_cmd; this option remains for backwards compatibility.

--query
    Queries the service state and prints it as human-readable text.

--long
    Expands some fields in --query output (for example category lists). Can only be used with --query.

--query-raw
    Similar to --query, but prints raw proto-encoded bytes of tracing_service_state.proto.

--detach KEY
    Detach from tracing session using the given key.

--attach KEY
    Re-attach to a detached tracing session using the given key.

--stop
    Stop tracing once re-attached. Supported only with --attach.

--is_detached KEY
    Checks whether the session can be re-attached. Exit code semantics: 0 yes, 2 no, 1 error.

-h, --help
    Prints out help text for the perfetto tool.

SIMPLE MODE
For ease of use, the perfetto command includes support for a subset of configurations via command line arguments. On-device, these configurations behave equivalently to the same configurations provided by a CONFIG_FILE (see below).

The general syntax for using perfetto in simple mode is as follows:

         adb shell perfetto [ --time TIMESPEC ] [ --buffer SIZE ] [ --size SIZE ]
             [ --app APP_NAME ]
            [ ATRACE_CAT | FTRACE_GROUP/FTRACE_NAME]...

The following table lists the available options when using perfetto in simple mode.

-t, --time TIME[s|m|h]
    Specifies the trace duration in seconds, minutes, or hours. For example, --time 1m specifies a trace duration of 1 minute. The default duration is 10 seconds.

-b, --buffer SIZE[mb|gb]
    Specifies the ring buffer size in megabytes (mb) or gigabytes (gb). The default parameter is --buffer 32mb.

-s, --size SIZE[mb|gb]
    Specifies the max file size in megabytes (mb) or gigabytes (gb). By default perfetto uses only in-memory ring-buffer.

-a, --app APP_NAME
    Specifies an Android app name for atrace app-level tracing.

This is followed by a list of event specifiers:

ATRACE_CAT
    Specifies the atrace categories you want to record a trace for. For example, the following command traces Window Manager using atrace: adb shell perfetto --out FILE wm. To record other categories, see the https://cs.android.com/android/platform/superproject/main/+/main:frameworks/native/cmds/atrace/atrace.cpp list of atrace categories . Note: Available categories are Android version dependent.

FTRACE_GROUP/FTRACE_NAME
    Specifies the ftrace events you want to record a trace for. For example, the following command traces sched/sched_switch events: adb shell perfetto --out FILE sched/sched_switch

NORMAL MODE
The general syntax for using perfetto in normal mode is as follows:

         adb shell perfetto [ --txt ] --config CONFIG_FILE

The following table lists the available options when using perfetto in normal mode.

-c, --config CONFIG_FILE
    Specifies the path to a configuration file. In normal mode, some configurations may be encoded in a configuration protocol buffer. This file must comply with the protocol buffer schema defined in AOSP trace_config.proto. You select and configure the data sources using the DataSourceConfig member of the TraceConfig, as defined in AOSP data_source_config.proto. Use - to read config bytes from stdin.

--txt
    Instructs perfetto to parse the config file as pbtxt. This flag is not a stable API and is not recommended for production.