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80 lines
3.0 KiB
80 lines
3.0 KiB
4 months ago
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# Quickstart: Record traces on Linux
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Perfetto can capture system traces on Linux. All ftrace-based data sources
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and most other procfs / sysfs-based data sources are supported.
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Currently there are no packages or prebuilts for Linux. In order to run Perfetto
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on Linux you need to build it from source.
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## Building from source
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1. Check out the code:
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```bash
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git clone https://android.googlesource.com/platform/external/perfetto/ && cd perfetto
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```
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2. Download and extract build dependencies:
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```bash
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tools/install-build-deps
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```
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_If the script fails with SSL errors, try invoking it as `python3 tools/install-build-deps`, or upgrading your openssl libraries._
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3. Generate all most common GN build configurations:
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```bash
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tools/build_all_configs.py
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```
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4. Build the Linux tracing binaries (On Linux it uses a hermetic clang toolchain, downloaded as part of step 2):
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```bash
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tools/ninja -C out/linux_clang_release traced traced_probes perfetto
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```
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_This step is optional when using the convenience `tools/tmux` script below._
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## Capturing a trace
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Due to Perfetto's [service-based architecture](/docs/concepts/service-model.md),
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in order to capture a trace, the `traced` (session daemon) and `traced_probes`
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(probes and ftrace-interop daemon) need to be running.
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For a quick start, the [tools/tmux](/tools/tmux) script takes care of building,
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setting up and running everything.
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As an example, let's look at the process scheduling data, which will be obtained
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from the Linux kernel via the [ftrace] interface.
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[ftrace]: https://www.kernel.org/doc/Documentation/trace/ftrace.txt
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1. Run the convenience script with an example tracing config (10s duration):
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```
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OUT=out/linux_clang_release CONFIG=test/configs/scheduling.cfg tools/tmux -n
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```
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This will open a tmux window with three panes, one per the binary involved in
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tracing: `traced`, `traced_probes` and the `perfetto` client cmdline.
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2. Start the tracing session by running the pre-filled `perfetto` command in
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the down-most [consumer] pane.
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3. Detach from the tmux session with `Ctrl-B D`,or shut it down with
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`tmux kill-session -t demo`. The script will then copy the trace to
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`/tmp/trace.protobuf`, as a binary-encoded protobuf (see
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[TracePacket reference](/docs/reference/trace-packet-proto.autogen)).
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## Visualizing the trace
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We can now explore the captured trace visually by using a dedicated web-based UI.
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NOTE: The UI runs fully in-browser using JavaScript + Web Assembly. The trace
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file is **not** uploaded anywhere by default, unless you explicitly click
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on the 'Share' link.
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1. Navigate to [ui.perfetto.dev](https://ui.perfetto.dev) in a browser.
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2. Click the **Open trace file** on the left-hand menu, and load the captured
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trace (by default at `/tmp/trace.protobuf`).
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3. Explore the trace by zooming/panning using WASD, and mouse for expanding
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process tracks (rows) into their constituent thread tracks.
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Press "?" for further navigation controls.
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Alternatively, you can explore the trace contents issuing SQL queries through
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the [trace processor](/docs/analysis/trace-processor).
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