139738 2014-12-17 11:49:59 -0800 [iOS] run-webkit-tests significantly slows down when running the last bunch of tests 2022-02-12 19:08:30 -0800 1 1 1 Unclassified WebKit Tools / Tests 528+ (Nightly build) iPhone / iPad iOS 8.1 RESOLVED CONFIGURATION CHANGED InRadar P2 Normal --- 1 dbates webkit-unassigned ap bfulgham ddkilzer webkit-bug-importer oldest_to_newest 1056487 0 dbates 2014-12-17 11:49:59 -0800 I noticed when using run-webkit-tests to run iOS layout tests using WebKit1 an WebKit2 that the rate at which tests are run significantly slows down as run-webkit-tests nears completion. This behavior tends to be more noticeable when running large batches of tests (> 10000). I am using a Mac Pro with 2 x 2.66 GHz 6-Core Intel Xeon processors, 12 GB RAM, OS X Yosemite (14A378) with a debug build of WebKit at r177430. I invoke run-webkit-tests to run tests using WebKit2 with a command line of the form: Tools/Scripts/run-webkit-tests --ios-sim --runtime com.apple.CoreSimulator.SimRuntime.iOS-[...] --device-type com.apple.CoreSimulator.SimDeviceType.iPhone-5s --no-sample-on-timeout --results-directory layout-test-results-rebase -2 [...] (I omit the argument -2 in the above command to run the specified tests using WebKit1). When invoked with [...] as the empty string (i.e. to run the full suite of layout tests), run-webkit-test will run 24 instances of WebKitTestRunnerApp.app in parallel. 1056491 1 webkit-bug-importer 2014-12-17 12:04:19 -0800 <rdar://problem/19282201> 1056518 2 ap 2014-12-17 13:04:43 -0800 Is it just that some workers finish, and there are only a few of them remaining at the end? Running run-webkit-tests with --debug-rwt-logging should tell.