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This paper introduces an optically interconnected distributed shared memory system. The distributed shared memory approach integrates both shared memory and distributed memory system ideas to extract the strengths of each while balancing their respective weaknesses. The system is a system based on a photonic network to support the high communication requirement of . The employs wavelength division multiple access on the photonic network, enabling multiple channels to be formed on a single optical fiber. A result of the high communication capacity is the simplification of the global address mapping problem. This simplified uniform address allocation scheme is introduced. The advantages of the proposed approach are examined through a performance analysis based on a closed queueing network which has been validated through extensive simulation. The performance of the system is evaluated in terms of transaction time of a memory request and system throughput. The impact of variations in the number of channels and processors in the system on these metrics is studied. The effect of variations in memory and channel service times are also evaluated.

Software distributed shared memory (DSM) provides a convenient and effective solution for programming parallel applications on distributed systems. However, the performance of current implementations suffers from large overhead in enforcing memory coherence. Coherence faults are the sources of massive network traffic. Various memory consistency models have been proposed in order to eliminate the effects of network traffic and memory latency. In this paper, we present a novel approach that combines relaxed memory consistency models and a compiler strategy to solve memory coherence problems for DSM. This approach produces fewer coherence faults. Experimental results also show this hybrid approach is effective for reducing the memory coherence overhead of DSM.

In this paper, we present fundamental mechanisms for global process and memory management in an efficient single system image cluster operating system designed to execute workloads composed of high performance sequential and parallel applications. Their implementation in Kerrighed, our proposed distributed operating system, is composed of a set of Linux modules and a patch of less than 200 lines of code to the Linux kernel. Kerrighed is a unique single system image cluster operating system providing the standard Unix interface as well as distributed OS mechanisms such as load balancing on all cluster nodes. Our support for standard Unix interface includes support for multi-threaded applications and a checkpointing facility for both sequential and shared memory parallel applications. We present an experimental evaluation of the Kerrighed system and demonstrate the feasibility of the single system image approach at the kernel level.

Recently, distributed shared memory systems have received much attention because such an abstraction simplifies programming. In this paper, we present a simple protocol which implements the linearizability consistency criterion in a distributed shared memory system. Unlike previously implemented protocols, our protocol is based on an optimistic approach. The protocol eliminates the necessity of potentially expensive synchronization among processors for each write operation, but may require processes to rollback.

Existing user-level network interfaces deliver high bandwidth, low latency performance to applications, but are typically unable to support diverse styles of communication and are unsuitable for use in multiprogrammed environments. Often this is because the network abstraction is presented at too high a level, and support for synchronisation is inflexible.

In this paper we present a new primitive for in-band synchronisation: the Tripwire. Tripwires provide a flexible, efficient and scalable means for synchronisation that is orthogonal to data transfer. We describe the implementation of a non-coherent distributed shared memory network interface, with Tripwires for synchronisation. This interface provides a low-level communications model with gigabit class bandwidth and very low overhead and latency. We show how it supports a variety of communication styles, including remote procedure call, message passing and streaming.