What Is the Price of Simplicity? A Cross-Platform Evaluation of the SAGA API

摘要

The abundance of middleware to access grids and clouds and their often complex APIs hinders ease of programming and portability. The Open Grid Forum (OGF) has therefore initiated the development and standardization of SAGA: a Simple API for Grid Applications. SAGA provides a simple yet powerful API with high-level constructs that abstract from the details of the underlying infrastructure. In this paper we investigate the price that possibly comes with such an API. We discuss the effects on expressiveness and ease of programming, and analyze the performance overhead of three different SAGA implementations (written in Java, Python, and C++) on various middleware. We conclude that SAGA is a good pragmatic approach to make grids easily accessible. The API considerably improves usability and uniformity, but offers a compromise between expressiveness and runtime dependencies. The overall performance of the tested implementations is acceptable, but the strict API semantics require various runtime checks that occasionally cause significant overhead, depending on the underlying infrastructure.