Evaluating support for global address space languages on the Cray X1

The Cray X1 was recently introduced as the first in a new line of parallel systems to combine high-bandwidth vector processing with an MPP system architecture. Alongside capabilities such as automatic fine-grained data parallelism through the use of vector instructions, the X1 offers hardware support for a transparent global-address space (GAS), which makes it an interesting target for GAS languages. In this paper, we describe our experience with developing a portable, opensource and high performance compiler for Unified Parallel C (UPC), a SPMD global-address space language extension of ISO C. As part of our implementation effort, we evaluate the X1’s hardware support for GAS languages and provide empirical performance characterizations in the context of leveraging features such as vectorization and global pointers for the Berkeley UPC compiler. We discuss several difficulties encountered in the Cray C compiler which are likely to present challenges for many users, especially i...

• Type: Conference
• Year: 2004
• Where: ICS
• Authors: Christian Bell, Wei-Yu Chen, Dan Bonachea, Katherine A. Yelick
• Keywords: Berkeley UPC Compiler, GAS Languages, ICS 2004, Theoretical Computer Science, X1 Offers Hardware