We'll respond shortly.
Q: A team is looking for options to test their app’s response times under load. What’s the recommended tool?
A: Browser Mob was recommended as a hosted option. They have scripted browsers that make requests against your site.
Tsung is an Erlang project that can send a bunch of traffic to your site.
Q: Is it possible to deploy without downtime to Heroku?
A: The closest option is to have two apps that share a single database and coordinate your deploys and A/B which one serves the app publicly. This is clunky. Perhaps Heroku is working on a supported solution for rolling restarts of dynos.