We propose a methodology to effectively characterize the architecture and system performance of distributed systems designed to operate in frame-based real-time environments. Important characteristics that define the real-time performance of a distributed system are identified and classified at the hardware, operating system, and user application levels. A synthetic workload model, called the Distributed Real-Time Workload (DRTW), is designed to fully characterize a broad range of real-time applications and to exercise a single- or multiple-node distributed system under measurement. A set of data collection tools to obtain empirical performance data at different levels of a distributed system is also proposed. For the purpose of illustration, these tools are used to obtain data on several real-time systems from Encore Computer Corporation.