Memory-Efficient and Skew-Tolerant MapReduce Over MPI for Supercomputing Systems
Tao Gao, Yanfei Guo, Boyu Zhang, Pietro Cicotti, Yutong Lu, Pavan Balaji, Michela Taufer · IEEE Transactions on Parallel and Distributed Systems · 2020
Data analytics has become an integral part of large-scale scientific computing. Among various data analytics frameworks, MapReduce has gained the most traction. Although some efforts have been made to enable efficient MapReduce for supercomputing systems, they are often limited to fairly homogeneous workloads where equal partitioning of input data across tasks results in essentially equal output or temporary data generated on each task. For workloads that are more skewed, however, current implementations can result in imbalance in memory usage and, consequently, can cause a slowdown in execution time and a loss in data scalability. To tackle this problem, we enhance a previously published memory-conscious MapReduce over MPI framework called Mimir. Our enhancements to Mimir include combiner and dynamic repartition optimizations to minimize and balance memory usage and to achieve close to optimal balance of the memory usage across processes and to reduce the execution time by up to 12 times. Experimental results show that Mimir can scale to at least 3072 processes on the Tianhe-2 supercomputer on skewed datasets.