NEW 161547
REGRESSION: [mac-wk2 debug] LayoutTest tiled-drawing/scrolling/fixed/four-bars-zoomed.html is a flaky failure
https://bugs.webkit.org/show_bug.cgi?id=161547
Summary REGRESSION: [mac-wk2 debug] LayoutTest tiled-drawing/scrolling/fixed/four-bar...
Ryan Haddad
Reported 2016-09-02 13:57:57 PDT
LayoutTest tiled-drawing/scrolling/fixed/four-bars-zoomed.html is a flaky failure This test is a flaky failure on mac-wk2 debug bots https://build.webkit.org/builders/Apple%20Yosemite%20Debug%20WK2%20(Tests)/builds/14759 https://webkit-test-results.webkit.org/dashboards/flakiness_dashboard.html#showAllRuns=true&tests=tiled-drawing%2Fscrolling%2Ffixed%2Ffour-bars-zoomed.html --- /Volumes/Data/slave/yosemite-debug-tests-wk2/build/layout-test-results/tiled-drawing/scrolling/fixed/four-bars-zoomed-expected.txt +++ /Volumes/Data/slave/yosemite-debug-tests-wk2/build/layout-test-results/tiled-drawing/scrolling/fixed/four-bars-zoomed-actual.txt @@ -43,9 +43,9 @@ (coverage rect 0.00, 0.00 341.30 x 254.35) (intersects coverage rect 1) (contentsScale 2.30) - (tile cache coverage 0, 0 341 x 445) - (tile size 785 x 512) - (top left tile 0, 0 tiles grid 1 x 2) + (tile cache coverage 0, 0 445 x 445) + (tile size 512 x 512) + (top left tile 0, 0 tiles grid 2 x 2) (children 4 (GraphicsLayer (position -4.00 -4.00)
Attachments
Ryan Haddad
Comment 1 2016-09-07 13:06:19 PDT
First failure according to the dashboard is ~r204892, but that change itself seems unrelated.
Alexey Proskuryakov
Comment 2 2016-09-08 13:54:45 PDT
Ryan Haddad
Comment 3 2016-09-09 12:04:38 PDT
Alexey Proskuryakov
Comment 4 2016-09-20 22:44:08 PDT
I can reproduce this 100% by simply running the test alone: run-webkit-tests LayoutTests/tiled-drawing/scrolling/fixed/four-bars-zoomed.html Or, it reproduces 50 times like this: run-webkit-tests LayoutTests/tiled-drawing/scrolling/fixed/four-bars-zoomed.html --repeat 50 --no-retry -v --run-singly
Alexey Proskuryakov
Comment 5 2016-09-20 22:44:51 PDT
The test has a 10 ms timer, which is never good in regression tests.
Alexey Proskuryakov
Comment 6 2016-09-20 22:50:20 PDT
And if I change the timeout to 1000 ms, then the results are different yet. Simon, is logging tile sizes meaningful at all? Are there any common techniques for deflaking tests of this kind?
Simon Fraser (smfr)
Comment 7 2016-09-21 08:40:45 PDT
Seems like the test is racing with the tile-size timer. I wonder if we could turn off dumping of the tile caches for this test.
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