User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:18.0) Gecko/20100101 Firefox/18.0
Build ID: 20130116073211
Steps to reproduce:
1. Navigated to http://voxeljs.com/
2. Selected the "voxel forest" demo (http://substack.net/projects/voxel-forest/)
Firefox froze for a minute or so, The animated loader was visible but not rotating. Could not switch between tabs.
Firefox should have stayed responsive while loading the demo.
Confirmed against Mozilla/5.0 (Windows NT 6.1; WOW64; rv:21.0) Gecko/20130127 Firefox/21.0 ID:20130127031042.
Did the slow script dialog show up for you? I got one. The first time I used it to stop the script, and things seemed to be OK after that. I tried it again and let the script continue, and that eventually worked too.
(In reply to Reece H. Dunn from comment #3)
> I didn't see the slow script dialog on FF18, Firefox was frozen while it was
Hmmm, I was testing in Nightly. I just tried again in Fx18 (this time on Mac), and I still got the slow script dialog. I have seen cases before where the slow script dialog should have appeared, but didn't, but I don't know when or why.
This may or may not be a perf bug. Once the demo gets going, I get a 10% better frame rate in Fx than in Chrome. But the app doesn't time startup, and I didn't either, so it's possible the app startup is slower than it should be.
*** Bug 847218 has been marked as a duplicate of this bug. ***
The page hung for me, but not for so long. It didn't even made the slow script dialog show up.
Checking about:telemetry I see
Hang Report #1 (8 seconds)
js::GCMarker::processMarkStackTop(js::SliceBudget &) (in mozjs.pdb)
js::GCMarker::drainMarkStack(js::SliceBudget &) (in mozjs.pdb)
GCCycle (in mozjs.pdb)
Collect (in mozjs.pdb)
js::GCSlice(JSRuntime *,js::JSGCInvocationKind,JS::gcreason::Reason,__int64) (in mozjs.pdb)
js_InvokeOperationCallback(JSContext *) (in mozjs.pdb)
js::jit::InterruptCheck(JSContext *) (in mozjs.pdb)
js::jit::CheckOverRecursed(JSContext *) (in mozjs.pdb)