http://trac.webkit.org/browser/trunk/PerformanceTests/Layout/subtree-detaching.html is very noisy: http://webkit-perf.appspot.com/graph.html#tests=[[8408562,2001,173262],[8408562,2001,32196]]&sel=1349139712989,1349744512989&displayrange=7&datatype=running and took 112s to run on Chromium Mac: http://build.webkit.org/builders/Chromium%20Mac%20Release%20%28Perf%29/builds/6462/steps/perf-test/logs/stdio We need to fix this test.