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cc...@google.com
I think at this level of depth, you're best off writing queries within ui.perfetto.dev to navigate (type ':' in the search bar to start querying in the main view), since we don't have a way to navigate you to those sections, or give you more information about them.
E.g. in ui.perfetto.dev, write the query:
SELECT * FROM slice
INNER JOIN thread_track on slice.track_id = thread_track.id
INNER JOIN thread USING(utid)
INNER JOIN process USING(upid)
WHERE (process.name like "<PROCESS_NAME>" and slice.name like "<SLICE_NAME>") ORDER BY dur DESC
LIMIT 10
Note that if you select all of the info from the slice table ("SELECT * from slice" at the beginning), you can click any of these slices in the query result at the bottom to jump right to them.
You can then turn this into a metric, e.g. mapping the results from that query to measurements.
I think maybe on macrobench side, things to improve are:
-
document or more easily support this sort of query (public version of traceProcessor.querySlices for example, which queries everything and filters to targetPackage if desired)
-
give metrics (or some parallel system) a way to link you to interesting parts of the trace (which may become more possible with Studio support for ui.perfetto.dev linking)
ml...@google.com
I thought something a bit different, not sure I have it specified in my mind anyway (need to think about it)
Something more like this: I have a parent section, for example Compose:recompose, which might have multiple children that should show one after another (serial execution).
I'd like to get the longest children sections to basically understand what takes the longest within a given parent.
This gives us a framework to get information what executes the longest in traces and where we might spend the most time optimizing.
Description
Would it be possible to retrieve
Nlongest trace sections given some criteria?Let's say I have benchmarks on CI that track regular metrics like startup or frames. Alternatively, I'm exploring some app and don't have much information about it.
To better understand where should I focus, I would like to understand the most impactful trace sections within a section to understand what might contribute the most to janky UI.
Technically, I could dive into the perfetto trace and create a query that would order N slices by
dur, but could we do something like this from metrics? Something like "give me 10 longest sections withinCompose:recomposesection` when composition tracing is enabled.I'm not sure metric outputs would be ready for something like this and/or if this is reasonable/feasible.