Using shared memory for read-mostly RPC services

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 remote procedure calls (RPC) 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 efficient access to server data by client read-sharing of some server objects and methods. Local client calls to read-only 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 performance close to an unprotected implementation, but with the modularity and server protection of traditional RPC