just to be sure. we define a Thread as accessing the parent shared process memory and the splitting according to en.wikipedia.org/wiki/Thread_(computing) ? if so the answer hast to be yes we need to split the threads.
Right on. As per your awesome Wikipedia link, "These threads share the process's resources, but are able to execute independently. " Imagine worker threads being able to write directly to the framebuffers used by canvas elements. Wow. Cool huh?