Cache Lockout Policy for Error Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Data processing devices face issues with erroneous data storage and retrieval in caches due to hard and soft errors, which existing error protection modules and lockout schemes struggle to address effectively, leading to potential hardware failures and performance impacts.
Innovation Solution
A programmable cache lockout policy is implemented using lockout bits and a cache control module that manages the lockout state of cache lines, allowing for flexible error management by adjusting the lockout policy and generating interrupts based on error types, thereby isolating erroneous cache lines and preventing them from being used for data access or storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a lockout scheme is implemented to isolate erroneous cache lines, then data integrity is improved, but device complexity increases due to additional control logic and interrupt management
Solution Approach 1:
The patent segments the cache system by introducing individual lockout bits for each cache line, allowing independent isolation of erroneous lines. The error protection module is divided into distinct functional components: error detection logic, lockout control logic, and interrupt generation logic, enabling modular management of complexity while maintaining data integrity.
Solution Approach 2:
The patent implements dynamic control of the lockout mechanism through a programmable cache control register that allows runtime configuration of lockout policy. The interrupt enable bit can be dynamically adjusted to control whether interrupts are generated, providing adaptability in error handling strategies based on system conditions and reducing unnecessary complexity.
2Loss of time
If interrupts are generated for every error detected, then error response time is improved, but productivity decreases due to increased interrupt overhead and performance impact
Solution Approach 1:
The patent introduces a dynamic interrupt control mechanism through an interrupt enable bit in the cache control register. This allows the system to adaptively enable or disable interrupt generation based on error severity and system conditions, balancing rapid error response with minimal performance overhead by generating interrupts only when necessary.
Solution Approach 2:
The patent changes the parameter of interrupt generation from a fixed always-on mode to a configurable mode controlled by the interrupt enable bit. This parameter change allows the system to optimize between rapid error response (interrupts enabled) and performance efficiency (interrupts disabled), resolving the contradiction between response time and productivity.
3Ease of operation
If a fixed lockout policy is implemented, then ease of operation is improved, but adaptability decreases when different error types require different handling strategies
Solution Approach 1:
The patent transforms the lockout policy from a fixed configuration to a dynamic, programmable control structure. The cache control register contains dedicated bits for lockout enable, interrupt enable, and lockout mode selection, allowing the policy to be changed at runtime without hardware redesign, thus providing both ease of operation and adaptability.
Solution Approach 2:
The patent creates a universal error handling framework where a single cache control register and lockout mechanism can handle multiple error types and scenarios through programmable configuration. The same hardware structure adapts to different error handling strategies (immediate lockout, delayed lockout, interrupt-based, or silent lockout) based on the configured policy, achieving versatility without complicating operation.
Data Source
AI summary
A data processing device includes a cache having a plurality of cache lines. Each cache line has a lockout state that indicates whether an error has been detected for data accessed at the cache line. The lockout state of a cache line is indicated by a set of one or more lockout bits associate with the cache line. When a cache line is in a locked-out state, the cache line is not used by the cache. Accordingly, a locked-out cache line is not employed by the cache to satisfy a cache accesses, and is not used to store data retrieved from memory in response to a cache miss. In response to determining the detected error likely did not result from a hardware failure or other persistent condition, memory error management software can reset the lockout state of the cache line.