Execution-time Prediction for Dynamic Streaming Applications with Task-level Parallelism

Programmable multiprocessor systems-on-chip are becoming the preferred implementation platform for embedded streaming applications. This enables using more software components, which leads to large and frequent dynamic variations of data-dependent execution times. In this context, accurate and conservative prediction of execution times helps in maintaining good audio/video quality and reducing energy consumption by dynamic evaluation of the amount of on-chip resources needed by applications. To be effective, multiprocessor systems have to employ the available parallelism. The combination of task-level parallelism and task delay variations makes predicting execution times a very hard problem. So far, under these conditions, no appropriate techniques exist for the conservative prediction of execution times with the required accuracy. In this paper, we present a novel technique for this problem, exploiting the concept of scenario-based prediction, and taking into account the transient and periodic behavior of scenarios and the effect of scenario transitions. In our MPEG-4 shape-decoder case study, we observe no more than 11% average overestimation.