AbstractPerformance analysis is essential to fully exploit the potential of high‐performance computers. With the imminence of petascale systems which will consist of ten thousands or even hundred thousands of processor cores, this task will increase in complexity. Hence, tools are required that automatically detect the performance bottlenecks and thus ease the performance analysis of an application. On large‐scale systems, collecting information about performance‐relevant events of an application can easily produce a huge amount of data whose analysis is very challenging. Aggregating the performance data during runtime and conducting the search for performance properties online allows users to distill essential performance bottlenecks without overwhelming the user with an uncontrollable load of data. In this paper we present the recent developments on Periscope, a highly scalable tool for the automatic distributed online search for the performance properties of large‐scale applications on high‐end computers. It allows for both detection of the performance bottlenecks limiting the scalability on parallel systems as well as pinpointing the issues concerning the single‐node performance of an application. Copyright © 2009 John Wiley & Sons, Ltd.