ACE - LINGUISTIC MECHANISMS FOR CUSTOMIZABLE PROTOCOLS

Customizing the protocols used to manage accesses to different data st ructures within an application can improve the performance of shared-m emory programs substantially [10, 21]. Existing systems for using cust omizable protocols are, however, hard to use because they force progra mmers to rely on low-level mechanisms for manipulating these protocols . Since several shared-memory systems implement protocols in software and can support customizable protocols, the development of intuitive a bstractions for the use of application-specific protocols is important . We have designed a language, Ace, that integrates support for custom izable protocols with minimal extensions to C. Ace applications are de veloped using the standard shared-memory model with a default sequenti ally consistent protocol. Performance can then be optimized, with mino r modifications to the application, by experimenting with different pr otocol libraries. In this paper, we isolate the issues involved in pro viding language support for using customizable protocols and present n ovel language abstractions for their easy use. We describe the impleme ntation of a compiler and runtime system for Ace, and discuss the issu es involved in their design. We also present measurements that demonst rate that Ace has good performance compared to an efficient software d istributed shared-memory system.