Component used: Version used: Latest (1.3.0-alpha04) Devices/Android versions reproduced on: all devices

TL;DR

Macrobenchmark tests fails with IllegalArgumentException: At least one result is necessary when using FrameTimingMetric together with tooling that adds trace sections to the root of the main thread section stacks. See attached screenshot for an example of what that might look like.

Details

FrameTimingQuery (source) makes the assumption that frames can be located by looking for "Choreographer#doFrame%" sections at the top of the main thread section stack. This is explicitly called on in a query comment:

---- parent_stack_id = 0 to filter to top of trace stack
            ( slice.name LIKE "Choreographer#doFrame%" AND process.pid LIKE thread.tid AND slice.parent_stack_id = 0)

Unfortunately, this assumption is broken when 3rd party code inserts additional sections to the top of the main thread section stack.

For example, the papa library adds a top trace section to every running main thread section (source), leveraging the logged name provided through Looper.getMainLooper().setMessageLogging() (see screenshot for what that looks like).

Side note 1: I'm aware that Looper.getMainLooper().setMessageLogging() wasn't exactly designed for this purpose, but having toString() details for all messages that run on the main thread is incredibly useful to help understand perfetto traces. Ideally there would be a dedicated API to help understand what runs on main.

Side note2: if anyone using papa runs into this issue, you can disable the additional tracing with a boolean resource override for R.bool.papa_trace_main_thread. Unfortunately that will make your perfetto traces a lot less easy to investigate.