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Browse Prior Art Database

Buffer Replacement Management With Locality Detectors

IP.com Disclosure Number: IPCOM000037448D
Original Publication Date: 1989-Jan-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Liu, L: AUTHOR

Abstract

Status upgrading of data least recently used (LRU), when brought into a cache, can be done with greater assurance that a succession of hits are not transient in nature by bringing the data first to a locality detector.

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Buffer Replacement Management With Locality Detectors

Status upgrading of data least recently used (LRU), when brought into a cache, can be done with greater assurance that a succession of hits are not transient in nature by bringing the data first to a locality detector.

Although upgrading management is performed on some or all lines in a cache in a processor, a locality detector device is added. It is a set-associative or fully-associative directory with only a few entries. All data or only selected accesses, such as vector operands, problem state data operands, or software designated data, may be first assigned to the locality detector that also has a replacment strategy, for example, LRU or first in-first out (FIFO). When a relevant line L is accessed by the control processor, the following occurs: 1. If L is found, its status is adjusted according to the assigned management policy. No adjustment of replace ment status is carried out in the cache itself unless there is a cache miss; in that case, the line may be brought in with proper LRU rank. 2. If L is not found, a new entry for L is created in the locality detector. This may result in replacement of an existing entry from the detector. The replacement status of L in the cache is upgraded to higher rank of most recently used (MRU) according to the cache manage ment scheme. In case of a cache miss, the fetching of L and LRU status assignment will be similar to the preceding paragraph.

A locality detector is...