New Relic has what looks like a really nice tool for monitoring Rails applications. It’s called RPM and it looks to give some really good insight into where performance bottlenecks occur in a Rails app.

37signals reported some excellent results after a round of performance tuning based on their findings from RPM.

Your mileage may vary. But RPM looks to be one of a very small number (perhaps the number 1) of tools that can help in this way with performance analysis, which is the first step to performance improvement.

Definitely worth a look if you’re doing any Rails development.