I'm 60% confident that the regression in bug 1227663 is due to the addon shim layer sending synchronous IPC traffic to the parent when it's busy measuring something unrelated. We need to get these Talos addons off the shims stat.
:mconley, can you elaborate on what this is. We are working on signing the talos addons and they need small modifications to be successfully signed. i would rather do the proper cleanup!
(In reply to Joel Maher (:jmaher) from comment #1) > :mconley, can you elaborate on what this is. We are working on signing the > talos addons and they need small modifications to be successfully signed. i > would rather do the proper cleanup! By default, any old-style add-ons that don't set <em:multiprocessCompatible>true</em:multiprocessCompatible> in their install.rdf's will activate the browser CPOW shims, which makes it easier for them accidentally use them (for example, setting a load event listener on a <xul:browser>, which will cause load events in the content process to be synchronously dispatched to and handled in the parent). We should make all of the Talos add-ons multiprocess-compatible to disable the shims, and fix any that are broken by this.
Stanley, this might be a good bug for you to pick up!