Cache Memory Sector-Level Dirty Bit Management
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Solution Overview
Problem
Conventional electronic devices face challenges in minimizing power consumption and maintaining data consistency due to errors during cache line fill and flush operations, which can lead to unnecessary data storage and increased power consumption.
Innovation Solution
The implementation of a cache memory system that manages dirty information in units of sector rather than cache lines, using a data mask signal to selectively store data in memory devices, thereby minimizing errors and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cache line flush operations are performed to ensure data consistency, then data reliability is improved, but power consumption increases due to unnecessary data storage
Solution Approach 1:
The patent segments the dirty bit management from cache line level to sector level within the cache line. Each sector has its own dirty bit, allowing selective flushing of only the modified sectors rather than the entire cache line. This segmentation enables precise control over which data portions are flushed to memory, avoiding unnecessary power consumption from flushing unchanged data while maintaining data consistency for modified portions.
Solution Approach 2:
The patent applies local quality by treating different sectors within a cache line differently based on their modification status. Instead of uniformly flushing entire cache lines, the system selectively flushes only those sectors that have been modified (indicated by dirty bits set to logic high). This localized approach ensures data consistency only where needed while minimizing unnecessary memory operations and power consumption.
2Reliability
If all sector data are stored in memory devices during cache flush, then data consistency is maintained, but power consumption increases due to unnecessary storage operations
Solution Approach 1:
The patent segments the flush operation into sector-level granularity using individual dirty bits for each sector. The memory controller examines each sector's dirty bit and selectively transfers only modified sectors to the memory device. This segmentation prevents unnecessary energy loss by avoiding the transfer and storage of unchanged data portions that would otherwise consume power during the flush operation.
Solution Approach 2:
The patent applies partial action by performing flush operations only on the necessary portion of data (modified sectors) rather than the entire cache line. The memory controller uses dirty bits to identify which sectors require flushing and executes storage operations only for those sectors, avoiding excessive action that would waste energy on storing unchanged data while still maintaining data consistency for the modified portions.
3Device complexity
If dirty bits are managed at cache line level, then management is simpler, but data management precision is reduced leading to unnecessary operations
Solution Approach 1:
The patent segments the dirty bit structure from a single cache line-level bit into multiple sector-level bits within the cache line. Each sector has its own dirty bit, providing precise tracking of modifications at the sector level. This segmentation increases management precision without significantly increasing overall complexity, as the segmented structure is systematically organized and managed by the memory controller through standardized operations.
Data Source
AI summary
An electronic device includes a cache memory including a memory space for storing a first cache set including a plurality of sector data and a plurality of dirty bits, each of the plurality of dirty bits representing whether corresponding sector data of the plurality of sector data are modified, a memory controller, connected to a plurality of data lines and a data mask line, for receiving the plurality of sector data and the plurality of dirty bits from the cache memory, setting a logic level of a data mask signal based on a logic level of each of the plurality of dirty bits, and outputting the plurality of sector data through the plurality of data lines and the data mask signal through the data mask line, and a memory device, connected to the plurality of data lines and the data mask line, for receiving the plurality of sector data through the plurality of data lines, and receiving the data mask signal through the data mask line.