A Design Method of Coarse Structure Directory Based on Counter

Abstract

The invention discloses a method for designing a coarse-structure directory based on a counter, which belongs to the technical field of computer system structure; based on a directory-based Cache consistency protocol, when a shared data block requests exclusive authority, the coarse-structure directory controller records according to the shared list of directory items Send copy invalidation or update message to the processor with valid copy of the data block in the system, the shared list vector of each directory entry in the coarse structure directory corresponds to a group of processors, and any processor in each group of processors has a data block When the copy is valid, the corresponding position is 1, otherwise it is 0; set a counter for each group of processors, and record the number of processors that are valid copies in the group, and only when the count of the counter corresponding to the processor group is greater than 0, the sent data is invalid or Update message: The present invention reduces copy invalidation or excessive broadcast of update messages by introducing a counter in the traditional rough structure directory to record the number of shared copies in the processor group.

Description

technical field [0001] The invention discloses a method for designing a rough structure catalog based on a counter, and belongs to the technical field of computer system structures. Background technique [0002] Although the traditional full mapping directory is simple to implement and can accurately record the copy information of the system's shared storage blocks to avoid invalid message broadcasts, the hardware storage overhead of the shared list of directory items implemented using the full mapping method is too large, which is not conducive to system expansion. Therefore, a large-scale multi-core multi-processor system usually uses a more compact directory structure design, such as a limited directory or a coarse directory (coarse directory). In the traditional coarse structure directory, all processors in the system are numbered and grouped, and each group of processors corresponds to a bit in the shared list vector. When a certain processor has a valid copy of the da...

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Problems solved by technology

[0004] The present invention aims at the problem of excessive broadcasting of messages caused by the inability to judge the copy situation in the processor in the traditional coarse-structured directory, and provides a method for designing a coarse-structured directory based on a counter. ) introduces a counter (counter) to record the number of shared copies in the processor group to reduce copy invalidation or excessive broadcast of update messages

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