Invention Grant
US08015364B2 Method and apparatus for filtering snoop requests using a scoreboard
有权
使用记分板过滤窥探请求的方法和装置
- Patent Title: Method and apparatus for filtering snoop requests using a scoreboard
- Patent Title (中): 使用记分板过滤窥探请求的方法和装置
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Application No.: US12129289Application Date: 2008-05-29
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Publication No.: US08015364B2Publication Date: 2011-09-06
- Inventor: Matthias A. Blumrich , Alan G. Gara , Thomas R. Puzak , Valentina Salapura
- Applicant: Matthias A. Blumrich , Alan G. Gara , Thomas R. Puzak , Valentina Salapura
- Applicant Address: US NY Armonk
- Assignee: International Business Machines Corporation
- Current Assignee: International Business Machines Corporation
- Current Assignee Address: US NY Armonk
- Agency: Scully, Scott, Murphy & Presser, P.C.
- Agent Daniel P. Morris, Esq.
- Main IPC: G06F12/00
- IPC: G06F12/00 ; G06F13/00

Abstract:
An apparatus for implementing snooping cache coherence that locally reduces the number of snoop requests presented to each cache in a multiprocessor system. A snoop filter device associated with a single processor includes one or more “scoreboard” data structures that make snoop determinations, i.e., for each snoop request from another processor, to determine if a request is to be forwarded to the processor or, discarded. At least one scoreboard is active, and at least one scoreboard is determined to be historic at any point in time. A snoop determination of the queue indicates that an entry may be in the cache, but does not indicate its actual residence status. In addition, the snoop filter block implementing scoreboard data structures is operatively coupled with a cache wrap detection logic means whereby, upon detection of a cache wrap condition, the content of the active scoreboard is copied into a historic scoreboard and the content of at least one active scoreboard is reset.
Public/Granted literature
- US20080294850A1 METHOD AND APPARATUS FOR FILTERING SNOOP REQUESTS USING A SCOREBOARD Public/Granted day:2008-11-27
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