| Summary: | 碩士 === 國立成功大學 === 電機工程研究所 === 83 === In this thesis, efforts are devoted to the design and
implementation of lazy release consistency (LRC) on
Cohesion which is a distributed shared memory system
developed in our laboratory. Release consistency is a more
relaxed protocol in comparison with the well-known sequential
consistency and it can be implemented by either lazy or
eager algorithm. The lazy release protocol guarantees the
shared data becoming consistent at a processor when the
processor acquires the synchronization object. It implies that
no consistency is enforced for the shared accesses between the
synchronization points. The lazy algorithm is better than the
eager one because it requirs fewer messages sent across the
interconnection network while maintaining the consistency.
However, LRC needs more complicated data structures and
operations to keep trace of the internal state of each page.
Cohesion supports a simple thread model that makes the
multithreaded parallel program development available.
By exploiting the multithreading technique, we may overlap
the computation and the network transfer to hide the latency
incurred in sending data across network. However, the
implementation of LRC in the multithreaded environment is more
complicate and some of the policies must be reconsidered and
be refined. We have implemented LRC on Cohesion without
the assistant of special preprocessor or compiler. From
experimental results, we find out that the false sharing is
remedied, the number of message is reduced and a better
performance can be achieved.
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