REGRESSION(r268161?): [ macOS ] imported/w3c/web-platform-tests/webaudio/the-audio-api/the-audiocontext-interface/processing-after-resume.https.html is a flaky failure

• Component: New Bugs
• Status: RESOLVED FIXED

[Hector Lopez]

imported/w3c/web-platform-tests/webaudio/the-audio-api/the-audiocontext-interface/processing-after-resume.https.html

Test is a flaky failure according to history on macOS. First occurrence of failure is at r268163 but I believe the change that restarted the testing for this test at r268161 might be a better regression point.

History:

https://results.webkit.org/?suite=layout-tests&test=imported%2Fw3c%2Fweb-platform-tests%2Fwebaudio%2Fthe-audio-api%2Fthe-audiocontext-interface%2Fprocessing-after-resume.https.html&platform=mac

Diff:

--- /Volumes/Data/slave/catalina-debug-tests-wk2/build/layout-test-results/imported/w3c/web-platform-tests/webaudio/the-audio-api/the-audiocontext-interface/processing-after-resume.https-expected.txt
+++ /Volumes/Data/slave/catalina-debug-tests-wk2/build/layout-test-results/imported/w3c/web-platform-tests/webaudio/the-audio-api/the-audiocontext-interface/processing-after-resume.https-actual.txt
@@ -1,3 +1,3 @@
 
-PASS Test consistency of processing after resume()
+FAIL Test consistency of processing after resume() assert_equals: node1 processed frame count expected 128 but got 0

[Radar WebKit Bug Importer]

<rdar://problem/70159546>

[Hector Lopez]

Test expectation while investigated:

https://trac.webkit.org/changeset/268301/webkit

[Chris Dumez]

Looks like I was able to reproduce like so:
 Tools/Scripts/run-webkit-tests imported/w3c/web-platform-tests/webaudio/the-audio-api/the-audiocontext-interface/processing-after-resume.https.html  --repeat-each=100 -g --additional-env-var=JSC_collectContinuously=true --force -1

Diff:
@@ -1,3 +1,3 @@

-PASS Test consistency of processing after resume()
+FAIL Test consistency of processing after resume() assert_equals: construct time before resume expected 0.19156462585034015 but got 0.20317460317460317

[Chris Dumez]

Created attachment 413068 [details]
Patch

[youenn fablet]

Comment on attachment 413068 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=413068&action=review

> Source/WebCore/ChangeLog:13
> +        still increase a bit, a short while after the suspend promise has been resolved. To address the issue, we now to a round

s/to/do/

> Source/WebCore/platform/audio/cocoa/AudioDestinationCocoa.cpp:132
> +        dispatchToRenderThread(WTFMove(callCompletionHandlerOnMainThread));

dispatchToRenderThread takes a function not a completion handler.
Should we make it take a CompletionHandler? It seems it should always call the function in normal cases.

[Chris Dumez]

Comment on attachment 413068 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=413068&action=review

>> Source/WebCore/platform/audio/cocoa/AudioDestinationCocoa.cpp:132
>> +        dispatchToRenderThread(WTFMove(callCompletionHandlerOnMainThread));
> 
> dispatchToRenderThread takes a function not a completion handler.
> Should we make it take a CompletionHandler? It seems it should always call the function in normal cases.

I do not believe this is currently possible because there is an assertion in CompletionHandler enforcing that the CompletionHandler gets called on the thread it was constructed on.

[Chris Dumez]

Created attachment 413164 [details]
Patch

[EWS]

Committed r269383: <https://trac.webkit.org/changeset/269383>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 413164 [details].

[Diego Pino]

The only test filed under this bug was:

  - imported/w3c/web-platform-tests/webaudio/the-audio-api/the-audiocontext-interface/processing-after-resume.https.html

GTK post-commit test bot reports the test has been failing consistently for the last 4000 revisions.

Diff:

--- /home/buildbot/worker/gtk-linux-64-release-tests/build/layout-test-results/imported/w3c/web-platform-tests/webaudio/the-audio-api/the-audiocontext-interface/processing-after-resume.https-expected.txt
+++ /home/buildbot/worker/gtk-linux-64-release-tests/build/layout-test-results/imported/w3c/web-platform-tests/webaudio/the-audio-api/the-audiocontext-interface/processing-after-resume.https-actual.txt
@@ -1,3 +1,3 @@
 
-PASS Test consistency of processing after resume()
+FAIL Test consistency of processing after resume() assert_equals: construct time before resume expected 0.06965986394557823 but got 0.07546485260770976