PROLAS: a Novel Dynamic Load Balancing Library for Advanced Scientific Computing
Mississippi State University
Bridges, Susan M.
Little, R. Rainey
Date of Degree
Graduate Thesis - Open Access
Master of Science
College of Engineering
Department of Computer Science and Engineering
Scientific and engineering problems are often large, complex, irregular and data-parallel. The performance of many parallel applications is affected by factors such as irregular nature of the problem, the difference in processor characteristics and runtime loads, the non-uniform distribution of data, and the unpredictable system behavior. These factors give rise to load imbalance. In general, in order to achieve high performance, dynamic load balancing strategies are embedded into solution algorithms. Over time, a number of dynamic load balancing algorithms have been implemented into software tools and successfully used in scientific applications. However, most of these dynamic load balancing tools use an iterative static approach that does not address irregularities during the application execution, and the scheduling overhead incurred is high. During the last decade, a number of dynamic loop scheduling strategies have been proposed to address causes of load imbalance in scientific applications running in parallel and distributed environments. However, there is no single strategy that works well for all scientific applications, and it is up to the user to select the best strategy and integrate it into the application. In most applications using dynamic load balancing, the load balancing algorithm is directly embedded in the application, with close coupling between the data structures of the application and the load balancing algorithm. This typical approach leads to two disadvantages. First, the integration of each newly developed load balancing algorithm into the application needs to be performed from scratch. Second, it is unlikely that the user has incorporated the optimal load balancing algorithm into the application. Moreover, in a certain application (of various problem sizes and number of processors), it is difficult to assess in advance the advantage of incorporating one load balancing algorithm versus another. To overcome these drawbacks, there is a need for developing an application programming interface (API) for dynamic load balancing scientific applications using the recently developed dynamic loop scheduling algorithms. This thesis describes the design and development of such an API, called ProLAS, which is scalable, and independent of data structures of a host application. ProLAS performance is evaluated theoretically and experimentally (after being used in scientific applications). A qualitative and quantitative analysis of ProLAS is presented by comparing its performance with the state of the art technology in dynamic load balancing tools (e.g. CHARM++ library) for parallel applications. The analysis of the experimental results of using ProLAS in a few scientific aplications indicate that it consistently outperforms the existing technology in dynamic load balancing.
Krishnan, Manoj Kumar, "PROLAS: a Novel Dynamic Load Balancing Library for Advanced Scientific Computing" (2003). Theses and Dissertations. 3658.