Part of the Microprocessors glossary:

Memory coherence is a desirable condition in which corresponding memory locations for each processing element in a multi-core processor always contain the same cached data. Without memory coherence, programs can be adversely affected.

In multi-core processors, two or more processing elements work concurrently. Once in a while they will simultaneously access the same memory location. As long as no processing element alters the data at the affected location, all of those elements can share and cache the data without any problems. But if one of the processing elements changes the data in the shared location and does not inform the others of the change, the other elements might use the outdated version of the data that remains in their local caches.

In a multi-core processing system, a so-called memory coherence protocol notifies all the processing elements of changes to shared values, thereby ensuring that all copies of the data remain consistent.

This was last updated in July 2012
Contributor(s): Stan Gibilisco
Posted by: Margaret Rouse

Related Terms

Definitions

  • cache memory

    - Definition: Learn what cache memory is, what it has to do with RAM, how it is categorized and how it is configured. (SearchStorage.com)

  • quad-core processor

    - A quad-core processor is a chip with four independent units called cores that read and execute central processing unit (CPU) instructions such as add, move data, and branch. (WhatIs.com)

  • embedded device

    - An embedded device is an object that contains a special-purpose computing system. The system, which is completely enclosed by the object, may or may not be able to connect to the Internet. (WhatIs.com)

Glossaries

  • Microprocessors

    - Terms related to microprocessors, including definitions about silicon chips and words and phrases about computer processors.

  • Internet applications

    - This WhatIs.com glossary contains terms related to Internet applications, including definitions about Software as a Service (SaaS) delivery models and words and phrases about web sites, e-commerce ...

Ask a Question About memory coherencePowered by ITKnowledgeExchange.com

Get answers from your peers on your most technical challenges

Tech TalkComment

Share
Comments

    Results

    Contribute to the conversation

    All fields are required. Comments will appear at the bottom of the article.