Memory Device PPR Failure Handling With Thresholded Retries
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Solution Overview
Problem
Conventional computing devices face issues with Post Package Repair (PPR) failures in memory devices, leading to data loss and instability due to the limited number of spare memory subsystems, resulting in memory device disabling when PPR failures occur, especially during boot or runtime, which can cause system crashes.
Innovation Solution
A memory device PPR failure handling system that includes a memory management engine to identify PPR requests, perform PPR operations, increment failure counters, and disable memory devices when the failure count exceeds a threshold, preventing data loss and instability by retrying PPR operations before disabling the memory device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PPR operations are immediately disabled upon failure, then system stability is improved, but memory resource availability deteriorates
Solution Approach 1:
The system dynamically adjusts the response to PPR failures by implementing a retry mechanism with configurable thresholds. Instead of immediately disabling PPR operations upon first failure, the system allows a specified number of retry attempts before permanent disabling, making the failure handling adaptive rather than static.
Solution Approach 2:
The system prepares for potential PPR failures by establishing a retry buffer in advance. When a PPR operation fails, the system has pre-configured retry attempts available to cushion the impact of the failure, preventing immediate system instability while maintaining operational continuity.
2Quantity of substance
If PPR operations are retried multiple times before disabling, then memory resource availability is improved, but system stability deteriorates
Solution Approach 1:
The system implements feedback control by monitoring PPR operation outcomes and adjusting behavior based on failure patterns. Each failed PPR operation increments a failure counter, and when this counter reaches a predefined threshold, the system disables further retries, preventing instability from excessive retry attempts.
Solution Approach 2:
The system changes the operational parameters of PPR based on failure history. The retry threshold acts as a controllable parameter that determines when to transition from retry mode to disable mode, allowing flexible adjustment of system behavior based on observed failure patterns.
3Reliability
If spare memory subsystems are used for PPR remapping, then memory subsystem reliability is improved, but the number of available spare subsystems deteriorates
Solution Approach 1:
The system applies partial action by using only the necessary number of spare subsystems required to handle actual failures, rather than pre-allocating and permanently dedicating all spare subsystems. The retry mechanism ensures that spares are only consumed when absolutely necessary after exhausting retry options.
Data Source
AI summary
A memory device Post Package Repair (PPR) failure handling system includes a memory device having a first memory subsystem, and a memory management subsystem coupled to the memory device. The memory management subsystem identifies a first PPR request to perform first PPR operations on the first memory subsystem, and performs first PPR operations on the first memory subsystem based on the first current PPR request. The memory management subsystem may determine that the first PPR operations on the first memory subsystem have failed and, in response, increment a first PPR failure counter for the first memory subsystem, If, following the incrementing the first PPR failure counter for the first memory subsystem, the memory management subsystem determines that the first PPR failure counter for the first memory subsystem has reached a PPR failure count threshold, the memory management subsystem disables use of the memory device.