TrackEvent counter from different tracks has different range

[wangjiyang]

Hi,

I am using python perfetto lib to write track events sythetically. However, i found TrackEvent counter from different tracks has different range. This makes tracks difficult to compare. Eg, if i want to compare interrupt counts of different irq name, which resides in different tracks. If they have different range, lower value curves may actually have very big counter value, and developers may not notice it.

[LalitMaganti]

This is working as implemented as in most cases you don't want counters to share a y-axis but if the counters are linked, makes sense to change a y-axis range.

We'd be open to adding a "range key" option to the CounterDescriptor [1] which would allow you to indicate that all tracks with the same key and same parent id for the track should have the same y-axis in the UI. The code for this already exists in the UI through the use of the yRangeShareKey [2]. Would just require some plumbing work in trace processor to parse the proto (around [3]) + some work in the TrackEvent UI plugin to take advantage of this [4].

[1] https://source.chromium.org/chromium/chromium/src/+/main:third_party/perfetto/protos/perfetto/trace/track_event/counter_descriptor.proto;l=35?q=f:counter_descriptor&ss=chromium
[2] https://source.chromium.org/chromium/chromium/src/+/main:third_party/perfetto/ui/src/components/tracks/base_counter_track.ts;l=175?q=base_counter_track&ss=chromium%2Fchromium%2Fsrc:third_party%2Fperfetto%2Fui%2Fsrc%2F
[3] https://source.chromium.org/chromium/chromium/src/+/main:third_party/perfetto/src/trace_processor/importers/proto/track_event_event_importer.h;l=1244
[4] https://source.chromium.org/chromium/chromium/src/+/main:third_party/perfetto/ui/src/plugins/dev.perfetto.TrackEvent/index.ts;l=1?q=f:trackEvent%20f:index.ts&sq=&ss=chromium%2Fchromium%2Fsrc

[LalitMaganti]

Filed #2461 to track this.