As of r209827, 64-bit ARM and x86 WebKit ports use a new garbage collector called Riptide. Riptide reduces worst-case pause times by allowing the app to run concurrently to the collector. This can make a big difference for responsiveness since garbage collection can easily take 10 ms or more, even on fast hardware. Riptide improves WebKit’s performance on the JetStream/splay-latency test by 5x, wh