Without a doubt the build queue mechanism is the cause for the endless spin we see all too often on the Builder when testing and downloading an add-on. Whether we need to use a different task system, upgrade the current one, or stop using a task queue entirely, it has to happen ASAP, nothing is off the table.
I believe this is squashed with Wil/Sean's recent changes, shall I mark this fixed?
I still see some pretty good sized spikes on the graphs. Are you able to make it hang anymore?
Just testing around on builder.addons.mozilla.org, I'm still occasionally seeing 30+ second wait times for add-ons to install when I click "test".
@KWiero: Most recent changes that we're considering aren't live yet. They're on preview/stage.
I was actually looking at the wrong graphs. The trunk ones don't have enough data on them to be conclusive that this is fixed, but it's fair to say our patch addresses the main point of concern so I'll close this.