Adaptive Patrol Scrub Period for Memory ECC Power Optimization
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Solution Overview
Problem
Memory modules with on-die ECC capabilities face challenges in power consumption and memory throughput due to the need for continuous patrol scrubbing operations, which can lead to accumulation of bad data bits and potentially catastrophic system errors, especially in battery-based compute devices where power is a diminishing resource.
Innovation Solution
Implementing a programmable patrol scrub period based on the power status of an energy storage device, allowing the memory controller to set a schedule for error correction operations that adapts to the device's power state, such as shorter periods when discharging and longer periods when charging, to optimize power usage and prevent data corruption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous patrol scrubbing operations are performed at high frequency to prevent data corruption, then memory reliability is improved, but power consumption increases
Solution Approach 1:
The patent applies dynamics by making the patrol scrub frequency adaptive rather than fixed. The memory controller dynamically adjusts the scrubbing interval based on real-time power status detection - using higher frequencies when power is abundant (AC power) and lower frequencies when power is limited (battery power). This resolves the contradiction by allowing the system to maintain reliability when possible while conserving energy when necessary.
Solution Approach 2:
The patent changes the temporal parameter of patrol scrubbing frequency based on power conditions. By modifying the scrubbing interval parameter according to power status, the system can optimize between reliability and power consumption - using shorter intervals (higher frequency) when reliability is prioritized and longer intervals (lower frequency) when power conservation is needed.
2Reliability
If patrol scrubbing frequency is increased to prevent bad bit accumulation, then data error prevention is improved, but battery life deteriorates
Solution Approach 1:
The system dynamically adapts patrol scrub frequency based on power source detection. When AC power is detected, the system uses higher scrubbing frequencies to prevent bad bit accumulation. When battery power is detected, the system automatically reduces scrubbing frequency to extend battery life. This dynamic adjustment resolves the contradiction between data error prevention and battery life preservation.
Solution Approach 2:
The patent modifies the patrol scrubbing interval parameter based on power status. By changing this temporal parameter, the system balances data integrity requirements against battery conservation needs - using more frequent scrubbing when reliability is critical and less frequent scrubbing when extending battery operation is the priority.
3Reliability
If patrol scrubbing is performed at high rate to ensure no data errors, then memory reliability is improved, but power savings are reduced
Solution Approach 1:
The patent implements dynamic frequency adjustment of patrol scrubbing operations based on real-time power status monitoring. The system transitions between high-frequency mode (when AC power is available) and low-frequency mode (when battery power is available), allowing it to maximize power savings during battery operation while maintaining high reliability when AC power supplies the system.
Solution Approach 2:
By changing the patrol scrubbing frequency parameter according to power conditions, the system optimizes the balance between memory reliability and energy consumption. The parameter adjustment allows the system to achieve power savings during battery operation by reducing scrubbing frequency, while maintaining high reliability through increased frequency when AC power is available.
Data Source
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AI summary
In one implementation, a memory module with on-die error correction code (ECC) with scrub operation capabilities and a programmable patrol scrub period is coupled to a memory controller that causes error correction operations to perform based on a power status of an energy storage device.