Martin was impressed by New Relic's demonstration of Rails profiling (screen shots follow) I had the pleasure Friday of speaking with Lew Cirne and Mike Malloy of New Relic about RPM and RPM Lite, which as I discussed in July, make Rails site profiling easy using a SaaS model. These products compete with the free FiveRuns TuneUp service. (In other news, FiveRuns TuneUp now works with Merb.)RPM comes in four levels: Lite, which is free; Bronze, which costs $40 per month; Silver, which costs $85 per month; and Gold, which costs $200 per month. All EngineYard hosting customers get RPM Bronze for free. The functional differences between the levels have to do with the amount of historical data that is retained and various analysis capabilities.Cirne, who is CEO and founder of New Relic, previously founded Wily Technology, designed Introscope, and sold Wily to CA. “I took a year off from development after we sold Wily,” Cirne told me, “and kept thinking about what I’d do differently if I had the chance to do Introscope all over. RPM is the result.” One selling point of RPM is that it literally takes a few minutes to set up, and customers can find out useful information about their Rails sites almost instantly.As a demo, Cirne showed me (via WebEx) a live RPM session looking at Shopify, which hosts roughly 3,000 storefronts on four hosts. Below is a screen shot of the main control panel (click on the image to see it full size):You can zoom in on the application and see revealing performance graphs: I was especially taken with the bar chart listing the slowest controller actions.Drilling down further, you can look at scalability by graphing the relationship between throughput and response time. The color of the points indicates the time of day. Even a big Rails site can scale well, if the choke points are identified and fixed:If you want to dig into the causes of a controller’s slow response time, you can get all the way down to the level of individual SQL queries: I was impressed.An obvious next question would be how does this compare to FiveRuns TuneUp. I have to say that I can’t answer that right now, but perhaps a reader who has done the comparison with a real Rails site would share his or her experience, either in the comments below or by e-mailing me (martin_heller@infoworld.com). Software Development