Talk:Cache coherence

Merge

This article should not be merged with cache. Cache coherency is a distinct topic. Dennis 20:01, 18 Dec 2004 (UTC)

I agree. Suggest template removed? EdwardHades 11:36, 13 January 2007 (UTC)[reply]

Consistency vs coherency

Whoever wrote this needs to go back and make a couple of changes:

1. Cache consistency != cache coherency

Coherency has to do with what values can be returned from a read, consistency has to do with the propagation of writes and when written values can/will be returned by a read. Read Hennessey and Patteron's book Ch6 to get an overview.

2. It might be nice to give some different examples of different CC protocols. The three major families of protocols are broadcast snoop, directory based, and hybrid (the only hybrid I know of is the IBM X3, see http://www.realworldtech.com/includes/templates/articles.cfm?ArticleID=RWT042405213553&mode=print for a description of the hybrid broadcast, directory protocol.

David Kanter

Generalization

I think the article should be generalized to apply to any kind of cache, and make a clear distinction when it's speaking about the CPU cache and when not. I have also added the {{mergefrom}} tag for caching failure, as it is an artifact of cache incoherency. -- intgr 11:37, 6 December 2006 (UTC)[reply]

Please do not merge cache failure into this article Cache incoherency can lead to cache failure however as the that is but one of the many causes. Cache failure article also gives examples of failures in web browser caching that have nothing to do with coherency as defined today.