Sectored Cache Tag Structure for Reducing Storage Fragmentation
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Solution Overview
Problem
Current cache systems are inefficient in storing and retrieving data from multiple distinct blocks, leading to storage fragmentation and reduced cache capacity, which increases cache miss rates and energy consumption.
Innovation Solution
A sectored cache system with a tag array and data array, where a processor copies and updates data from memory into cache lines, using sector bit vectors and tag structures to efficiently store and index data from multiple blocks in a single cache line, reducing storage fragmentation and increasing effective cache capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If data from multiple distinct blocks is stored in separate cache lines, then data organization is simple, but storage fragmentation increases and cache capacity is reduced
Solution Approach 1:
The patent merges data from multiple distinct blocks into a single cache line by using a sectored cache structure. Instead of allocating separate cache lines for each block, the system divides cache lines into sectors and allows multiple blocks to share the same cache line by storing their data in different sectors. This is achieved through a tag structure that includes a sector bit vector field to track which sectors contain data from which blocks, effectively combining storage resources and reducing fragmentation while maintaining organized access through the tag array.
2Device complexity
If traditional cache tagging is used, then tag structure is simple, but tracking data from multiple blocks in a single cache line is inefficient
Solution Approach 1:
The patent segments the cache line into multiple sectors, with each sector capable of storing data from different blocks. The tag structure is enhanced with a sector bit vector field that provides a bit for each sector, allowing efficient tracking of which sectors contain valid data and from which blocks. This segmentation approach enables the system to track multiple blocks within a single cache line without significantly increasing tag structure complexity, as the bit vector provides compact representation of sector status.
3Device complexity
If cache capacity is reduced due to storage fragmentation, then storage management is simpler, but cache miss rates increase
Solution Approach 1:
The patent introduces a new dimension to cache organization by dividing cache lines into sectors along the data dimension. This allows the system to store data from multiple blocks in what would traditionally be considered a single-dimensional cache line structure. By adding the sector dimension and corresponding tag fields (sector bit vector, way field, start sector field), the system effectively increases cache capacity without complicating storage management, as the extended tag structure provides clear indexing and tracking mechanisms for the sectored organization.
Data Source
AI summary
Technologies are generally described for a system for copying particular data in a particular sector of a particular block from a memory into a cache, in some examples, the cache includes a tag array and a data array. In some examples, a processor may be adapted to copy data in the particular sector from the memory into a way of the data array starling at a start sector. In some examples, the processor may be adapted to update the tag array to identify the particular sector. In some examples, the processor may be adapted to update the tag array to identify the way in the data array, in some examples, the processor may be adapted to update the tag array to identify the start sector.