Dynamic reconfiguration of streaming graphs

Consumer electronics products are multi-functional devices that combine a set of media applications. Media data in such products is largely processed in heterogeneous multiprocessor subsystems that are integrated into a system on chip (SoC). A product engineer configures each subsystem for a collection of predefined applications when deploying the SoC in a product. Oftentimes, the system supports a large number of desired application configurations, or ‘use cases’. The system moves from one configuration to the next by adapting the configuration of a running application, referred to as ‘dynamic reconfiguration’. This paper presents a practical approach to dynamic application reconfiguration in a heterogeneous multiprocessor subsystem. The targeted media applications are constructed as a graph of concurrently executing interconnected tasks that exchange information through streams of data. Configuring such a streaming graph entails the instantiation and interconnection of tasks, setting of task parameters, assignment of tasks to coprocessors, and the allocation of communication buffers in memory. The paper derives a reconfiguration interface that can be supported in hardware, yet isolates application configuration knowledge from the coprocessor hardware. Though simple and easy to use, the interface addresses the key challenge of reconfiguring individual tasks while maintaining real-time behavior and data integrity of the overall set of concurrently executing applications. Keywords: streaming graph reconfiguration, multiprocessor architecture, MPEG-2, media processing, SoC subsystem 1