Hi All, At Qualcomm Innovation Center we have been working on a parallel algorithm for CSS styling and wanted to see if there is any interest in the community to see it implemented in WebKit. The overall idea is that we replace CSS matching and styling with a parallel implementation assuming there is a barrier before and after the computation. CSS style application will be performed by the main thread, such that we avoid the need to make thread safe data structures accessed in other passes. The algorithm is task-based, so we would need to implement a thread pool and a simple task scheduler (or maybe use an existing one).
In particular, our algorithm requires modifying Element::recalcStyle() and some of the methods it invokes. Code that calls Element::recalcStyle() will not have to be changed. By the time Element::recalStyle() returns, all threads involved on the parallel CSS styling have completed their execution. Effectively, there is a barrier when Element::recalcStyle() begins and another before it returns. Our experiments show that our CSS computation for complex websites scales rather well. For example, we observed that, for flickr.com, Webkit spends 75% of its time in CSS doing CSS matching. Thus, our algorithm would give a maximum speedup of 1.6X on 2 cores and 2.3X on 4 cores. Please let us know whether this would be of interest to the community. -Kulanthaivel _______________________________________________ webkit-dev mailing list [email protected] http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev
