Top Document: Comp.os.research: Frequently answered questions [3/3: l/m 13 Aug 1996] Previous Document: [1.5.1.3] Application-specific coherence Next Document: [1.5.3] Transfer and caching granularity See reader questions & answers on this topic! - Help others by sharing your knowledge From: Distributed systems Most parallel applications will use some sort of synchronisation system to order and control accesses to shared data before actually accessing the data. The most important thing to note in DSM systems is that just blindly using standard test and set operations on bytes in shared pages will produce a high fault rate; faults are usually expensive, making this approach unacceptable. Clouds merges locking with the cache consistency protocol, so that the user may obtain both a lock and the data in one network transaction. This system has the advantage that no invalidation messages are required, since the granting of the lock guarantees that there are no conflicting copies; it has the disadvantage that an explicit unlock/discard operation is required to release access to the data. This is acceptable in Clouds, as the DSM system was designed specifically to support object invocation, so it is easy to discard on a return. Munin provides a distributed lock mechanism using `proxy objects' to reduce network load. Proxy objects are maintained by a lock server on each node; when a thread wants to obtain a lock on an object, it attempts to lock the proxy instead. The server obtains the global lock if it is not already held locally. Global locking is done by negotiating with all the other lock servers in the system. Each lock may be migrated from server to server, and part of the Munin system allows objects to be migrated along with their locks. Other systems, such as IVY and Mermaid, use modified versions of classic multiprocessor synchronisation facilities. User Contributions: 1 UoowNen ⚠ Sep 24, 2021 @ 7:07 am buy zithromax online https://zithromaxazitromycin.com/ - buy zithromax online zithromax online https://zithromaxazitromycin.com/ - buy zithromax Comment about this article, ask questions, or add new information about this topic:Top Document: Comp.os.research: Frequently answered questions [3/3: l/m 13 Aug 1996] Previous Document: [1.5.1.3] Application-specific coherence Next Document: [1.5.3] Transfer and caching granularity Part1 - Part2 - Part3 - Single Page [ Usenet FAQs | Web FAQs | Documents | RFC Index ] Send corrections/additions to the FAQ Maintainer: os-faq@cse.ucsc.edu
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