AppDynamics, the newfangled application performance management house started in 2008 to cater to mission-critical web apps, has picked up a handsome $20 million C round led by Kleiner Perkins.

Its existing VCs Greylock Partners and Lightspeed Venture Partners also kicked in. With the new infusion it's raised a total of $36.5 million.

The start-up will use the new money to enhance its product and expand sales to extend the 400% growth in bookings it says it saw last year.

It puts the surge down to a shift in application architectures and growth in mission-critical cloud applications. It says "modern applications are no longer monolithic in nature but are highly distributed and dynamic, fueled by architectural trends such as cloud, SOA, Big Data and Agile development. As a result, traditional application performance management solutions have become obsolete."

Presumably it's thinking of IBM Tivoli, CA, Compuware and HP.

It figures its "low-touch sales model" - consisting of free downloads, no risk "try-before-you-buy" software trials and zero consulting services - helps. It claims 60,000 users for AppDynamics Lite, its free Java troubleshooting solution. The company's widgetry also works in .NET environments.

Customers include Netflix, Priceline, TiVo, ZipRealty, Taleo and Swisscom. On its web site it claims 50,000 users.