Supporting high level programming with high performance: the Illinois Concert system

Programmers of concurrent applications are faced with a complex performance space in which data distribution and concurrency management exacerbate the difficulty of building large, complex applications. To address these challenges, the Illinois Concert system provides a global names-pace, implicit concurrency control and granularity management, implicit storage management, and object oriented programming features. These features are embodied in a language ICC++ (derived from C++) which has been used to build a number of kernels and applications. As high level features can potentially incur overhead, the Concert system employs a range of compiler and runtime optimization techniques to efficiently support the high level programming model. The compiler techniques include type inference, inlining and specialization; and the runtime techniques include caching, prefetching and hybrid stack/heap multithreading. The effectiveness of these techniques permits the construction of complex parallel applications that are flexible, enabling convenient application modification or tuning. We present performance results for a number of application programs which attain good speedups and absolute performance.