Throughout most of our B2G test automation deployment, we’ve been very conscious about not enabling too many tests simply because we didn’t have enough capacity on our test slaves to run them all. Regardless it was still bad enough as it was (many of you probably experienced very long wait times for results). Thanks to releng (and especially Rail Aliiev) we are now running most of our B2G tests in Amazon AWS which means we can be much more flexible in accomodating load.