[webkit-dev] Slowest regression tests in debug builds

[Darin Adler]

Just out of curiosity, I used the "--slowest" option to see which tests were slowest in a debug build. On my fairly-fast Mac Pro the tests took 14 minutes overall (849.76s), and these were the ten slowest tests:

	9.57 secs: editing/selection/move-left-right.html
	7.64 secs: editing/selection/extend-selection.html
	6.91 secs: websocket/tests/frame-lengths.html
	6.67 secs: http/tests/cache/subresource-expiration.html
	5.41 secs: fast/js/toString-and-valueOf-override.html
	5.13 secs: http/tests/xmlhttprequest/small-chunks-response-text.html
	5.11 secs: http/tests/navigation/slowtimerredirect-basic.html
	5.06 secs: http/tests/navigation/slowmetaredirect-basic.html
	3.94 secs: http/tests/misc/acid3.html
	3.64 secs: fast/workers/worker-cloneport.html

Out of 11955 tests, these are 0.08% of the tests and they take 6.95% of the time. To me that means we might be able to speed things up quite a bit by tackling the slowest tests.

But making the test engine run tests on multiple cores in parallel could probably speed things up a lot more.

And I’m sure that release builds will be quite different.

It was not long ago when the entire run-webkit-tests process completed in 1 minute. 14 minutes is significantly different, and I’m wondering if there’s something we can do.

I have nothing specific to suggest, but wanted to share this data.

    -- Darin