[webkit-dev] parallel layout research

[Alex Russell]

After a discussion this morning about the potential for parallel CSS
layout with Erik Aarvidson, he pointed out a group at Berkeley doing
research in this area:

    http://www.eecs.berkeley.edu/~lmeyerov/projects/pbrowser/

The bits that jumped out to me were:

   * the source is available [0]
   * they've implemented an abstract language for describing the CSS
spec for parameterizing layout. It reminds me a lot of the work Badros
did circa 2000 [1]. They suggest that this model does layout of the
CSS 2.1 spec in time similar to the hand-tuned sequential engine in
Gecko [2]
   * using Cilk++ to handle low-level paralleism, they've seen
significant speedups beyond that for multi-core [2]

It's exciting to me to see this kind of parallelism being extracted
from CSS layout operations, which have shown up in profiling of Google
apps as a serious bottleneck. I hesitate to ask about the WebKit
community's interest in this since I assume that if patches show up
and can prove their value, they'll be accepted, but I would like to
know where people are either supportive or skeptical about such an
approach.

Regards

[0]: http://code.google.com/p/pbrowser/source/browse/#svn/trunk
[1]: http://www.badros.com/greg/papers/gjbadros-dissertation.pdf
[2]: http://www.eecs.berkeley.edu/~lmeyerov/projects/pbrowser/retreatwinter2009/playout.pdf
, slide #19