Bug 201012 – perf/clone-with-focus.html is a flaky failure

• Component: Tools / Tests
• Status: RESOLVED FIXED

[Russell Epstein]

The following layout test is a flaky failure on iOS:

perf/clone-with-focus.html

History:

https://webkit-test-results.webkit.org/dashboards/flakiness_dashboard.html#tests=perf%2Fclone-with-focus.html

We have some failures such as:

-PASS. Cloning elements takes roughly as long with as without focus.
+FAIL. Cloning 1000 elements with focus took 1ms, without took 0ms.

Where a difference of 1ms leads to a fail, leading to flakiness, which seems wrong given the nature of the test. Other failures (such as the provided diff) have slightly larger time differences.


Spoke with Ryosuke offline, who said the following:
"I think the test is written to fail when cloning with focus is twice is as slow as closing without focus. However, the issue is that the bot / WebKit has gotten fast enough that cloning without focus finishes within 0ms. So twice of that is still 0ms.

We need to increase the number of cloning steps such that the measurement for cloning without focus is at least 10ms."

Diff:

--- /Volumes/Data/slave/ios-simulator-12-release-tests-wk2/build/layout-test-results/perf/clone-with-focus-expected.txt
+++ /Volumes/Data/slave/ios-simulator-12-release-tests-wk2/build/layout-test-results/perf/clone-with-focus-actual.txt
@@ -1,2 +1,2 @@
 
-PASS. Cloning elements takes roughly as long with as without focus.
+FAIL. Cloning 1000 elements with focus took 5ms, without took 2ms.

[Radar WebKit Bug Importer]

<rdar://problem/54577399>

[Radar WebKit Bug Importer]

<rdar://problem/54577402>

[Ryosuke Niwa]

Created attachment 376951 [details]
Fixes the test

[Ryosuke Niwa]

Comment on attachment 376951 [details]
Fixes the test

View in context: https://bugs.webkit.org/attachment.cgi?id=376951&action=review

> LayoutTests/perf/clone-with-focus.html:34
> +            listElement.appendChild(originalItem);

This makes the test run faster.

[Ryosuke Niwa]

Thanks!

[Ryosuke Niwa]

Committed r248996: <https://trac.webkit.org/changeset/248996>