JTE : mémoires partagées réparties

A Persistent Distributed Shared Memory and its Garbage Collector
Marc Shapiro INRIA Rocquencourt and Microsoft Research Cambridge

Abstract: Collaborative applications need to share state across machines. Client-server technology is not adequate for these applications because of the need for disconnected operation and of the cost of remote access. Furthermore the shared data needs to be persistent.

We present PerDiS, a platform that transparently replicates shared information to client machines. PerDiS makes it simple to write applications thanks to automatic memory management. Extended transactions enable both isolation and cooperation. Reachable data is automatically persistent.

Garbage collection is a crucial issue in such a persistent store. We relate the principles of distributed garbage collection protocols that is independent of application semantics (in particular, of the coherence status of replicated data), does not impose any application or compiler changes, and minimizes overhead and interference.

We present some performance results from a proof-of-concept platform that runs a number of small, but real, distributed applications on Unix and Windows NT. These confirm that the PerDiS abstraction is well adapted to the targeted application area and that the overall performance is promising compared to alternative approaches.