We added new features for analyzing multiple programs to the IPS-2 parallel-program performance tools and were surprised at the wide range of performance problems for which this modified IPS-2 can be used. With multiapplication IPS-2, programmers can simultaneously run and analyze cooperating or contending applications; combine performance displays and metrics of multiple applications or multiple versions of the same application to directly compare performance; analyze critical paths of execution for individual applications, for a single application and the applications with which it interacts, or for entire workloads; study how the application workload performance affects the hardware, operating system, and network performance; study an application's evolution through multiple versions, hardware platforms, or input sets; study a workload's aggregate behavior, how applications interact, or how individual applications perform in the presence of other applications; and compare the measured performance of a program with predictions made by simulations or analytical models. This modified parallel-program performance tool analyzes multiple applications in a single session, allowing better performance tuning than is possible when programs are run in isolation.