1572337 - Monitor event delays to allow modeling of input event latency at any point

Status: RESOLVED FIXED

(Core :: Performance: General, enhancement)

Description

[Randell Jesup [:jesup] (needinfo me)]

We want to be able to get a finer-grained view of jank by inferring what would be the delay of a hypothetical input event at any point in time. By monitoring the queue and run-start times of events in threads, we can reconstruct what delays an input event would see at any given point. See mozilla.dev.platform post "Measuring interactivity in a browser (especially during load)" 2019/7/31 Message-ID: <[e-mail]>

We want to be able to visualize these delays in the profiler (and replace the existing inject-events-every-16ms responsiveness code). We also would like to be able to collect this data (outside the profiler) during raptor runs, and maybe at other times (devtools?)

Comment 1

[Randell Jesup [:jesup] (needinfo me)]

Attachment: Bug 1572337: Monitor running event delays and start times r=froydnj

Comment 2

[Randell Jesup [:jesup] (needinfo me)]

Attachment: Bug 1572337: replace Responsiveness measurement with Event delay measurements r=mstange

Depends on D41279

Comment 3

[Greg Tatum [:gregtatum]]

Hey there Randell. We're starting an effort to back-fill test coverage on all of our existing profiler features, in order to provide a more reliable product, especially as we're scaling up the users of the profiler. Would you mind adding a test to this new feature? I'd be happy to help point to some of our existing tests, and to review.

I know Gerald has been writing new unit tests for his new C++ machinery, but this feels like a good place to have a more integration style test.

For features that have different behaviors in the parent and content processes I've been using browser tests to ensure both pathways have coverage.

https://searchfox.org/mozilla-central/source/tools/profiler/tests/browser/browser_test_feature_jsallocations.js

For features that behave consistently no matter the process they are in, I've been using the faster xpcshell tests, e.g.

https://searchfox.org/mozilla-central/source/tools/profiler/tests/xpcshell/test_merged_stacks.js
https://searchfox.org/mozilla-central/source/tools/profiler/tests/xpcshell/test_feature_mainthreadio.js

Comment 4

[Randell Jesup [:jesup] (needinfo me)]

Attachment: Bug 1572337: ensure MainThread is registered with the profiler properly r=gerald

Comment 5

[Randell Jesup [:jesup] (needinfo me)]

Attachment: Bug 1572337: Test that we get non-0 responsiveness values in the profiler r=gregtatum

Depends on D41280

Comment 6

[Randell Jesup [:jesup] (needinfo me)]

Profile collected using this code to capture responsiveness: https://perfht.ml/2N8pV99

Comment 7

[Randell Jesup [:jesup] (needinfo me)]

Attachment: Bug 1572337: Make GetRunningEventDelay handle threadpools r=froydnj

Threadpools run an event that then runs other events, so we need to tweak
things for GetRunningEventDelay()

Depends on D41279

Comment 8

[Randell Jesup [:jesup] (needinfo me)]

Attachment: Bug 1572337: Remove old responsiveness profiler measurement r=gerald

Depends on D41280

Comment 9

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/ea6d5b4b038b
Monitor running event delays and start times r=froydnj

Comment 10

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/4eda65e054d8
ensure MainThread is registered with the profiler properly r=gerald

Comment 11

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/00da7156d3fa
Make GetRunningEventDelay handle threadpools r=froydnj

Comment 12

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/b3510afc9f79
replace Responsiveness measurement with Event delay measurements r=mstange

Comment 13

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/913d6bd82284
Remove old responsiveness profiler measurement r=gerald

Comment 14

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/fc8a37c2c22c
Test that we get non-0 responsiveness values in the profiler r=gregtatum

Comment 15

[Andrei Ciure[:aciure]]

Backed out changeset b3510afc9f79 (bug 1572337) for causing a linting failure in platform.cpp

push that caused the backout: https://treeherder.mozilla.org/#/jobs?repo=autoland&group_state=expanded&selectedJob=275080356&resultStatus=testfailed%2Cbusted%2Cexception%2Cusercancel%2Crunnable&revision=b3510afc9f796da5a0a5fb1a74eb0d4c96d5d494

backout: https://hg.mozilla.org/integration/autoland/rev/46f56b04700693c563081aa7a56a0f79b9e2176a

Comment 16

[Andrei Ciure[:aciure]]

Backed out 3 changesets (bug 1572337, bug 1594015) for causing linting failures and build bustages

Follow up to the backout above.

Comment 17

[Pulsebot]

Backout by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/3334e244dd72
Backed out 3 changesets (bug 1572337, bug 1594015) for causing linting failures and build bustages CLOSED TREE

Comment 18

[Razvan Maries]

Al changesets got backed out: https://treeherder.mozilla.org/#/jobs?repo=autoland&revision=9671d807910645adcfce06425bc2f734d9c5bf9e

Failures: https://treeherder.mozilla.org/#/jobs?repo=autoland&resultStatus=testfailed%2Cbusted%2Cexception&failure_classification_id=2&selectedJob=275088536

Comment 19

[Randell Jesup [:jesup] (needinfo me)]

Attachment: Bug 1572337: Don't call TimeStamp::Now() within SuspendAndSample r=froydnj

Avoids deadlocks on Windows

Depends on D41637

Comment 20

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/3d2bf6bfe931
ensure MainThread is registered with the profiler properly r=gerald
https://hg.mozilla.org/integration/autoland/rev/1eedae351266
Monitor running event delays and start times r=froydnj
https://hg.mozilla.org/integration/autoland/rev/e25cefd5d1d1
Make GetRunningEventDelay handle threadpools r=froydnj
https://hg.mozilla.org/integration/autoland/rev/1167a0ab6288
replace Responsiveness measurement with Event delay measurements r=mstange
https://hg.mozilla.org/integration/autoland/rev/fef6230f3cb2
Remove old responsiveness profiler measurement r=gerald
https://hg.mozilla.org/integration/autoland/rev/2c97624e0f19
Test that we get non-0 responsiveness values in the profiler r=gregtatum
https://hg.mozilla.org/integration/autoland/rev/620c4222c7f3
Don't call TimeStamp::Now() within SuspendAndSample r=froydnj

Comment 21

[Cosmin Sabou [:CosminS]]

https://hg.mozilla.org/mozilla-central/rev/3d2bf6bfe931
https://hg.mozilla.org/mozilla-central/rev/1eedae351266
https://hg.mozilla.org/mozilla-central/rev/e25cefd5d1d1
https://hg.mozilla.org/mozilla-central/rev/1167a0ab6288
https://hg.mozilla.org/mozilla-central/rev/fef6230f3cb2
https://hg.mozilla.org/mozilla-central/rev/2c97624e0f19
https://hg.mozilla.org/mozilla-central/rev/620c4222c7f3

Comment 22

[Florin Strugariu [:Bebe]]

== Change summary for alert #23812 (as of Mon, 11 Nov 2019 12:32:18 GMT) ==

Improvements:

11% perf_reftest_singletons external-string-pass.html macosx1014-64-shippable opt e10s stylo 1,138.65 -> 1,012.04

For up to date results, see: https://treeherder.mozilla.org/perf.html#/alerts?id=23812