Using Shared Memory for Read-Mostly RPC Services

This paper describes object-based runtime support for efficient access to protected objects, i.e., objects belonging to server programs that export protected services to untrusted clients. Modern operating systems use hardware-based protection domains to protect a server's objects; clients can access those objects only through cross-domain (RPC) calls to methods that execute within the server's domain. Unfortunately, exclusive use of RPC compromises performance in exchange for protection. We show how to provide safe and e#cient access to server data by client read-sharing of some server objects and methods. Local client calls to readonly methods execute directly in shared memory, without the cost of protection crossing. We introduce a version-based mechanism to synchronize the readers with write-methods executing in the server domain. Object-based proxies hide the use of shared memory from client programs. Measurements of a simple application demonstrate that our techniques can deliver p..