Compute total GC time wherever we compute new/old GC metrics - Githubissues

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Compute total GC time wherever we compute new/old GC metrics #108049

Open dnfield opened 2 years ago

dnfield commented 2 years ago

@jonahwilliams says we have this, but at least in the benchmark run I'm looking at I only see the GC counts and not the time. We should make sure that we get the total runtimes.

@a-siva FYI if you have further input

See https://ci.chromium.org/ui/p/flutter/builders/prod/Linux_android%20opacity_peephole_opacity_of_grid_perf__e2e_summary/2528/overview and specifically https://storage.googleapis.com/flutter_logs/flutter/81300293747d258587008c01f3a858275773006c/opacity_peephole_opacity_of_grid_perf__e2e_summary/01de952f-a9fb-4a52-a486-6d465dc5f872/e2e_perf_summary.json which has the GC counts but no times. That is further compounded by that benchmark not producing a full timeline, which is tracked in https://github.com/flutter/flutter/issues/108046

dnfield commented 2 years ago

Desired end state:

All tests that produce a timeline_summary.json, in addition to having a new_gen_gc_count and old_gen_gc_count, will also have the total time in GC, at least total time on UI thread but including total time on other threads would be helpful as well.
All tests that use PerfTest.e2e (or subclasses) or package:integration_test without producing a full timeline still produce total GC time.

Here are locations where we're doing something close to this:

https://github.com/dnfield/flutter/blob/7db25c36ad02d601dc9189264282df66d97765c3/packages/flutter_driver/lib/src/driver/timeline_summary.dart#L102-L102 (counts GCs but does not count time). Only used in tests that produce a timeline summary, i.e. flutter_driver tests
https://github.com/dnfield/flutter/blob/7db25c36ad02d601dc9189264282df66d97765c3/packages/flutter_driver/lib/src/driver/gc_summarizer.dart#L29-L29 Counts total UI thread time for GCs, but not number of GCs or time on other threads or types of GC. Only used in some tests.
https://github.com/dnfield/flutter/blob/7db25c36ad02d601dc9189264282df66d97765c3/packages/integration_test/lib/integration_test.dart#L366-L366 - only used in package:integration_test tests that explicitly call watchPerformance - so not used by PerfTest.e2e or its subclasses.