Julian has some measurements that suggest that rayon is burning a lot more cycles than it should. This bug tracks investigating that.
Rayon-0.7.0 can spin under certain circumstances that might sometimes happen with Stylo. This is tracked at https://github.com/nikomatsakis/rayon/issues/343. Ideally we can fix this in a Rayon-0.7.1 release and use that instead.
This is fixed with the pairing (rayon 0.7.1, rayon-core 1.0.2). Next is to update the m-c tree to use those versions.
Filed https://github.com/servo/servo/pull/17105 to update Servo's rayon dependency.
(In reply to Cameron McCormack (:heycam) from comment #3) > Filed https://github.com/servo/servo/pull/17105 to update Servo's rayon > dependency. Said PR has been merged.
(In reply to Nathan Froyd [:froydnj] from comment #4) > Said PR has been merged. Thanks!