Shared Cache Line Mode Switching for Storage Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Data processing systems face inefficiencies in cache storage capacity utilization due to the binary nature of cache mode operations (inclusive and non-inclusive modes), which either consume more storage for efficient data sharing or reduce sharing efficiency for storage savings.
Innovation Solution
A shared cache memory system that selectively operates on a cache line or range basis, switching between inclusive and non-inclusive modes based on transaction types, using state data to manage cache line storage and snoop requests, thereby optimizing storage capacity and sharing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the shared cache memory operates in inclusive mode to store cache lines in multiple caches, then data sharing efficiency is improved, but cache storage capacity is consumed
Solution Approach 1:
The patent applies dynamics by making the cache mode configurable and switchable between inclusive and non-inclusive modes. The system can dynamically adjust its operation mode based on workload characteristics, allowing it to adapt the balance between data sharing efficiency and storage capacity utilization in real-time
Solution Approach 2:
The patent changes the operational parameter of the shared cache memory by allowing configuration of inclusive vs non-inclusive mode. This parameter change enables the system to alter its behavior between prioritizing data sharing (inclusive mode) and prioritizing storage efficiency (non-inclusive mode)
2Quantity of substance
If the shared cache memory operates in non-inclusive mode to reduce storage usage, then cache storage capacity is saved, but data sharing efficiency deteriorates
Solution Approach 1:
The system dynamically switches between operational modes based on actual usage patterns, allowing it to adopt non-inclusive mode when storage efficiency is prioritized and inclusive mode when data sharing is more important, thus adapting to different workload scenarios
Solution Approach 2:
The patent enables parameter change in the cache operational mode, allowing the system to adjust the inclusivity parameter based on configuration or detected workload characteristics, thereby optimizing the trade-off between storage capacity and data sharing efficiency
3Ease of operation
If dedicated directory circuitry is used to control cache mode, then cache line mode control is achieved, but device complexity increases
Solution Approach 1:
The patent implements self-service by having the cache memory itself store and process the mode control information. The cache memory uses its own storage resources to hold mode data and processes control decisions internally, eliminating the need for separate dedicated control circuitry and reducing overall system complexity
Data Source
AI summary
A data processing system 2 includes a cache hierarchy having a plurality of local cache memories and a shared cache memory 18. State data 30, 32 stored within the shared cache memory 18 on a per cache line basis is used to control whether or not that cache line of data is stored and managed in accordance with non-inclusive operation or inclusive operation of the cache memory system. Snoop transactions are filtered on the basis of data indicating whether or not a cache line of data is unique or non-unique. A switch from non-inclusive operation to inclusive operation may be performed in dependence upon the transaction type of a received transaction requesting a cache line of data.