Sources
open directory project
Help build the largest human-edited directory on the web.
Submit a site - Become an editor
Wikipedia. Licensed under the GNU Free Documentation License.
Are you an expert in this subject? Join the discussion and share your knowledge at Wikipedia.org.
Shared memory
From Wikipedia, the free encyclopedia
In computer hardware, shared memory refers to a (typically) large block of random access memory that can be accessed by several different central processing units (CPUs) in a multiple-processor computer system.
A shared memory system is relatively easy to program since all processors share a single view of data and the communication between processors can be as fast as memory accesses to a same location.
The issue with shared memory systems is that many CPUs need fast access to memory and will likely cache memory,which has two complications:
- CPU-to-memory connection becomes bottleneck. Shared memory computers can not scale very well. Most of them have only ten processors.
- Cache coherence: Whenever one cache is updated with information that may be used by other processors, the change needs to be reflected to the other processors, otherwise the different processors will be working with incoherent data (see cache coherence and memory coherence). Such coherence protocols can, when they work well, provide extremely high performance access to shared information between multiple processors. On the other hand they can sometimes become overloaded and become a bottleneck to performance.
The alternatives to shared memory are distributed memory and distributed shared memory, with another, similar set of issues. See also Non-Uniform Memory Access.
- Shared Memory Architecture, where the graphics chip uses main system RAM
- Shared Memory Allocation
- Shared Memory Interface
- Shared Memory Library FAQ by Márcio Serolli Pinho
- Article "IPC:Shared Memory" by Dave Marshall
- shared memory facility from the Single UNIX® Specification
- shm_open - POSIX
- shmop - documentation from SunOS 5.9
- CreateSharedMemory function from Win32-SDK
- Functions in PHP-API
- Paper "A C++ Pooled, Shared Memory Allocator For The Standard Template Library" by Marc Ronell
- Citations from CiteSeer
- Linux Shared Memory Allocation with example
 |
Topics in Parallel Computing | |||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
||||||||||||||||||||||
 |
This computer-related article is a stub. You can help Wikipedia by expanding it. |