Partitioning Strategies for Concurrent Programming

This work presents four partitioning strategies, or design patterns, useful for decomposing a serial application into multiple concurrently executing parts. These partitioning strategies augment the commonly used task and data parallel design patterns by recognizing that applications are spatiotemporal in nature. Therefore, data and instruction decomposition are further distinguished by whether the partitioning is done in the spatial or in temporal dimension. Thus, this work describes four decomposition strategies: spatial data partitioning (SDP), temporal data partitioning (TDP), spatial instruction partitioning (SIP), and temporal instruction partitioning (TIP), while cataloging the benefits and drawbacks of each. These strategies can be combined to realize the benefits of multiple patterns in the same program. The practical use of the partitioning strategies is demonstrated through a case study which implements several different parallelizations of a multicore H.264 encoder for HD video. This case study illustrates the application of the patterns, their effects on the performance of the encoder, and the combination of multiple strategies in a single program.