Memory Command Insertion for Row Hammer Refresh Optimization
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Solution Overview
Problem
Current memory systems face limitations in communication efficiency between memory devices and controllers, particularly in addressing conditions initiated by memory devices, which can lead to increased power consumption and bandwidth usage due to statistical sampling techniques for row hammer refresh operations.
Innovation Solution
Implementing a command insertion signal trace to enable memory devices to communicate directly with the memory controller, allowing for deterministic identification and management of row hammer refresh operations, and performing these operations outside of traditional refresh time periods to reduce power demands and improve bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If statistical sampling techniques are used for row hammer refresh operations, then memory reliability is improved, but power consumption and bandwidth usage increase
Solution Approach 1:
The memory device autonomously monitors its own refresh requirements and generates refresh commands without requiring continuous controller intervention. The device uses its internal resources to track activation counts and determine when row hammer refreshes are needed, eliminating unnecessary refresh operations and reducing power consumption while maintaining reliability
Solution Approach 2:
The memory device performs preliminary monitoring of memory row activation counts and identifies potential row hammer conditions before they occur. By detecting conditions that can be addressed by refresh operations in advance, the system can perform targeted refreshes only when needed, rather than using continuous statistical sampling, thereby reducing unnecessary power consumption and bandwidth usage
2Reliability
If memory devices communicate with controllers through traditional interfaces, then communication is maintained, but communication efficiency and bandwidth are reduced
Solution Approach 1:
The patent introduces a new communication dimension by enabling memory devices to initiate commands directly to the controller through a dedicated command insertion interface. This breaks the traditional unidirectional controller-to-device communication model, allowing devices to proactively communicate refresh requirements and other conditions, thereby improving communication efficiency and reducing bandwidth constraints on traditional buses
3Stability of the object's composition
If row hammer refresh operations are performed during traditional refresh time periods, then memory stability is maintained, but system bandwidth and timing flexibility are limited
Solution Approach 1:
The system dynamically schedules row hammer refresh operations based on real-time memory conditions rather than adhering to fixed refresh time periods. The memory device monitors activation counts and triggers refresh operations when conditions indicate they are needed, allowing the system to adapt refresh timing to actual workload patterns. This maintains memory stability while significantly improving timing flexibility and bandwidth utilization
Data Source
AI summary
Memory devices and systems with memory-initiated command insertion (and associated methods) are disclosed herein. In one embodiment, a memory device comprises a command insertion terminal configured to be operably connected to a memory controller. The memory device can (i) identify a condition that can be addressed by receiving a command from the memory controller, and (ii) output, via the command insertion terminal, the command or an indication of the condition such that the command is inserted into a command queue of the memory controller. The memory device can include a command terminal over which the memory device can receive the command from the memory controller after the command is inserted in the command queue. In some embodiments, the condition can be a memory region of the memory device requiring a refresh cycle, and the command can be a command to perform a refresh cycle on the memory region.