DRAM Row Hammer Management via Dynamic Counter Increment
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Solution Overview
Problem
Existing memory devices face challenges in managing and preventing the memory row-hammering effect, especially as memory capacities increase and finer geometries are used, leading to increased resource consumption and lower critical hammering values.
Innovation Solution
A DRAM memory device with a logic block that implements hammer counters to quantify the row hammer effect based on activation and preload durations, and refreshes rows when the counter threshold is reached, thereby preventing the row hammer effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the scope of row hammering consideration is expanded to include rows beyond immediate neighbors, then the prevention effectiveness is improved, but the table size and resource consumption increase significantly
Solution Approach 1:
The patent divides the memory bank into sub-banks, where each sub-bank is monitored by its own counter. This segmentation allows the system to track row hammer effects in finer granules without requiring a single massive table to track all rows across the entire memory bank, thus reducing overall resource consumption while maintaining comprehensive protection.
Solution Approach 2:
The patent applies different monitoring strategies to different regions of the memory bank by using sub-bank level counters. Each sub-bank can be independently monitored and managed, allowing the system to focus resources on areas with higher hammering risk while using fewer resources for lower-risk areas, optimizing the balance between prevention effectiveness and resource consumption.
2Measurement precision
If the critical hammering value is reduced to account for finer geometries, then the prevention accuracy is improved, but the frequency of refresh operations increases
Solution Approach 1:
The patent uses dynamic counter incrementation where the increment value is not fixed but varies based on the detected row activation pattern. By adjusting the counter increment dynamically according to actual hammering conditions, the system can accurately detect row hammer effects at finer geometries while avoiding unnecessary refresh operations during normal operation, thus maintaining both precision and productivity.
Solution Approach 2:
The patent changes the parameter of counter increment value based on the activation pattern detected. Instead of using a fixed threshold, the system adjusts the increment parameter dynamically, allowing it to adapt to different operating conditions and geometry scales. This enables accurate detection at finer geometries without triggering excessive refresh operations under normal conditions.
3Ease of manufacture
If simple row activation counting is used, then the implementation simplicity is improved, but the performance penalty increases due to lack of dynamic adjustment
Solution Approach 1:
The patent introduces dynamic adjustment to the counter incrementation process by detecting row activation patterns and adjusting the increment value accordingly. This dynamic approach allows the system to maintain simple implementation while avoiding performance penalties, as the counter can adapt to different access patterns and reduce unnecessary refresh operations.
Solution Approach 2:
The patent implements feedback mechanisms where the system detects row activation patterns and uses this information to adjust counter incrementation. This feedback loop allows the system to learn from actual usage patterns and optimize its behavior, maintaining implementation simplicity while improving performance by reducing unnecessary refresh operations.
Data Source
AI summary
The invention relates to a memory device that comprises: —a memory bank provided with n memory rows, each row i being liable to effect a row hammer having a range p; —a block for preventing the hammer effect which comprises counting means implementing m hammer counters, each counter k being associated with one or more of the rows i, and is configured to increment a count k by an increment value kN, the increment value kN being a decreasing function of the duration TPN and also a function of the duration TAN, the increment value kN quantifying the effect of the hammer from the one or more rows i on rows j within hammering range; —a row refresh block configured to refresh one or more rows as soon as a count k reaches a threshold value M.