CSC/ECE 506 Spring 2012/11a hn: Difference between revisions

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==Distributed Shared Memory==
==Distributed Shared Memory==


In a [http://en.wikipedia.org/wiki/Distributed_shared_memory Distributed Shared Memory (DSM)] several processors share the same address space. It is a logical abstraction of a single address space which can be accessed by all processors. Instead of implementing shared memory model with a bus support the DSM uses a more scalable and less expensive model by supporting the abstraction of shared memory by using message passing. The main memory of a cluster of processors is made to look like a single memory with a single address space. Hence a processor can access a address space held by other processors main memory. The messages/mechanism used to get data to a processor from memory is hidden from the programmer and dealt internally.
In a [http://en.wikipedia.org/wiki/Distributed_shared_memory Distributed Shared Memory (DSM)] several processors share the same address space but unlike the shared memory machines they do not actually use a single memory, but it is a logical abstraction of a single address space which can be accessed by all processors. Instead of implementing shared memory model with a bus support the DSM uses a more scalable and less expensive model by supporting the abstraction of shared memory by using message passing. The main memory of a cluster of processors is made to look like a single memory with a single address space. Hence a processor can access a address space held by other processors main memory.  
===Hardware DSM===
===Hardware DSM===



Revision as of 05:33, 13 April 2012

Distributed Shared Memory

In a Distributed Shared Memory (DSM) several processors share the same address space but unlike the shared memory machines they do not actually use a single memory, but it is a logical abstraction of a single address space which can be accessed by all processors. Instead of implementing shared memory model with a bus support the DSM uses a more scalable and less expensive model by supporting the abstraction of shared memory by using message passing. The main memory of a cluster of processors is made to look like a single memory with a single address space. Hence a processor can access a address space held by other processors main memory.

Hardware DSM

Software DSM

Performance of DSM

Performance Improvement