A lightweight execution framework for massive independent tasks

This paper presents a lightweight framework for executing many independent tasks efficiently on grids of heterogeneous computational nodes. It dynamically groups tasks of different granularities and dispatches the groups onto distributed computational resources concurrently. Three strategies have been devised to improve the efficiency of computation and resource utilization. One strategy is to pack up to thousands of tasks into one request. Another is to share the effort in resource discovery and allocation among requests by separating resource allocations from request submissions. The third strategy is to pack variable numbers of tasks into different requests, where the task number is a function of the destination resource´s computability. This framework has been implemented in Gracie, a computational grid software platform developed by Peking University, and used for executing bioinformatics tasks. We describe its architecture, evaluate its strategies, and compare its performance with GRAM. Analyzing the experiment results, we found that Gracie outperforms GRAM significantly for execution of sets of small tasks, which is aligned with the intuitive advantage of our approaches built in Gracie.