Quickstart: Record traces on Linux

Perfetto can capture system traces on Linux. All ftrace-based data sources and most other procfs / sysfs-based data sources are supported.

Currently there are no packages or prebuilts for Linux. In order to run Perfetto on Linux you need to build it from source.

Building from source

  1. Check out the code:
git clone https://android.googlesource.com/platform/external/perfetto/ && cd perfetto
  1. Download and extract build dependencies:
tools/install-build-deps

If the script fails with SSL errors, try upgrading your openssl package.

  1. Generate the build configuration
tools/gn gen --args='is_debug=false' out/linux
# Or use `tools/setup_all_configs.py` to generate more build configs.
  1. Build the Linux tracing binaries (On Linux it uses a hermetic clang toolchain, downloaded as part of step 2):
tools/ninja -C out/linux tracebox traced traced_probes perfetto

Capturing a trace

Due to Perfetto's service-based architecture, in order to capture a trace, the traced (session daemon) and traced_probes (probes and ftrace-interop daemon) need to be running. As per Perfetto v16, the tracebox binary bundles together all the binaries you need in a single executable (a bit like toybox or busybox).

Capturing a trace with ftrace and /proc pollers, no SDK

If you are interested in overall system tracing and are not interested in testing the SDK, you can use tracebox in autostart mode as follows:

out/linux/tracebox -o trace_file.perfetto-trace --txt -c test/configs/scheduling.cfg

Testing the SDK integration in out-of-process tracing mode (system mode)

If you are using the Perfetto tracing SDK and want to capture a fused trace that contains both system traces events and your custom app trace events, you need to start the traced and traced_probes services ahead of time and then use the perfetto cmdline client.

For a quick start, the tools/tmux script takes care of building, setting up and running everything. As an example, let's look at the process scheduling data, which will be obtained from the Linux kernel via the ftrace interface.

  1. Run the convenience script with an example tracing config (10s duration):
tools/tmux -c test/configs/scheduling.cfg -C out/linux -n

This will open a tmux window with three panes, one per the binary involved in tracing: traced, traced_probes and the perfetto client cmdline.

  1. Start the tracing session by running the pre-filled perfetto command in the down-most [consumer] pane.

  2. Detach from the tmux session with Ctrl-B D,or shut it down with tmux kill-session -t demo. The script will then copy the trace to /tmp/trace.perfetto-trace, as a binary-encoded protobuf (see TracePacket reference).

Visualizing the trace

We can now explore the captured trace visually by using a dedicated web-based UI.

NOTE: The UI runs in-browser using JavaScript + Web Assembly. The trace file is not uploaded anywhere by default, unless you explicitly click on the ‘Share’ link. The ‘Share’ link is available only to Googlers.

  1. Navigate to ui.perfetto.dev in a browser.

  2. Click the Open trace file on the left-hand menu, and load the captured trace (by default at /tmp/trace.perfetto-trace).

  3. Explore the trace by zooming/panning using WASD, and mouse for expanding process tracks (rows) into their constituent thread tracks. Press “?” for further navigation controls.

Alternatively, you can explore the trace contents issuing SQL queries through the trace processor.