Debug Tracks

Debug Tracks are a way to display tabular results from running a PerfettoSQL query as a new so-called "debug" track. Specifically, if the resultant table can be visualised in a slice format (for example, the slice table), a debug track can be created from it.

For a result table to be able to be visualised in a slice format, it should include:

  1. A name (the name of the slice) column.
  2. A non-null timestamp (the timestamp, in nanoseconds, at the start of the slice) column.
  3. (Optionally) a duration (the duration, in nanoseconds, of the slice) column.

To create a new debug track:

  1. Run a SQL query, and ensure its results are slice-like (as described above). Query for debug track
  2. Navigate to the Timeline view, and click on "Show debug track" to set up a new debug track. Note that the names of the columns in the result table do not necessarily have to be name, ts, or dur. Columns which semantically match but have a different name can be selected from the drop-down selectors. Create a new debug track
  3. The debug track is visible as a pinned track near the top of the Timeline view with slices from the table from which the track was created (note that slices with no/zero duration will be displayed as instant events). The debug track may be manually unpinned and then it should appear on the top of other unpinned tracks. Resultant debug track