Joyent — the originators of the Ruby 1.8.5 DTrace provider and Ruby 1.8.6 DTrace provider — have set up a dedicated DTrace site, which Jason and company discuss in their latest podcast. If you are a Rails shop that cares about performance (and, yes, they very much exist), the resources at the Joyent page should become invaluable to you. And as long as we’re on the topic, if you’re in San Francisco this Tuesday (May 22nd), and you have fifteen clams burning a hole in your pocket, you might be interested in attending a panel that Jason and I will both be on: Ruby on Rails: To Scale or Not to Scale? (Once we have a few drinks in us, Jason and I also anticipate hosting a follow-up panel: “Jason Hoffman and Bryan Cantrill: Will the Real Doogie Howser Please Stand Up?”)