Architectural level analysis of a software system for its quality attributes is a proven cost-effective approach. This is particularly significant for performance, which defines multiple aspects of the quality of the system. In this paper we outline the contribution of a PhD, which provides architecture viewpoint based modeling and analysis support for parallelism and flow latency aspects of the performance, in legacy systems. The main contribution of the PhD includes Parallelism Viewpoint and Flow Latency Viewpoint. We use the proposed viewpoints to find parallelism and flow latencies specific performance bottlenecks of an industrial case, a precision critical electron microscope software system. The preliminary results of using Parallelism Viewpoint for our example case show that the viewpoint provides a profound insight into the thread-model of the system, which helps in reducing the excessively used parallelism in the system. Categories and Subject Descriptors: C.0 [Computer Syste...