928179 - Investigate why cycle collector doesn't merge compartments in three.js demo

Status: RESOLVED INCOMPLETE

(Core :: XPCOM, defect)

Description

[Andrew McCreight [:mccr8]]

If you load this demo:
  http://threejs.org/examples/webgl_materials_cars_camaro.html
...and hit reload in the middle of the loading, you get a CC that looks like this:

CC(T+151.9) duration: 1330ms, suspected: 1252, visited: 1632 RCed and 1065891 GCed, collected: 1090 RCed and 1065783 GCed (1066873|3 waiting for GC)

In theory, we should be trying to merge the JS compartments in the CC graph, and then we wouldn't get such a long CC, and it would be harder to blow up the hash table memory.  I should look into why that isn't happening...

Comment 1

[Andrew McCreight [:mccr8]]

Well, it looks like sometimes it works, so maybe this is just the heuristic being touchy, which isn't surprising:
CC(T+34.6) duration: 3348ms, suspected: 214, visited: 1100 RCed and 1183 merged GCed, collected: 979 RCed and 1080 GCed (2059|2 waiting for GC)

Comment 2

[Andrew McCreight [:mccr8]]

Compartment merging was a cool idea, but it basically failed in practice. I don't think having these old bugs around is useful. Maybe somebody can revive it, but they'd need to start over from the ground up.