Memory Controller Suspend Mode Switching for Read QoS
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Solution Overview
Problem
Existing memory devices face challenges in efficiently managing suspend operations, leading to reduced read quality of service (QoS) and reliability due to inconsistent suspend modes, particularly when program/erase operations are interrupted by read requests.
Innovation Solution
A memory controller and method that dynamically control the execution of suspend operations by a memory device, using a suspend operation manager to determine and adjust the suspend mode based on threshold comparisons and request sets, ensuring high read QoS and reliability by selecting between cancel and on-going modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the memory device uses a fixed suspend mode for all suspend operations, then the control logic is simple, but the read quality of service and reliability are reduced due to inconsistent performance across different operation scenarios
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed suspend mode to a dynamic suspend mode selection mechanism. The memory controller determines the appropriate suspend mode (cancel mode or on-going mode) based on real-time factors including the current operation state, number of suspend commands, and request queue depth. This dynamic adaptation resolves the contradiction by enabling the system to optimize reliability for each specific scenario while the underlying selection logic provides the necessary complexity management.
Solution Approach 2:
The patent changes the parameter of suspend mode from a static configuration to a dynamically adjustable parameter. By introducing variables such as suspend command count thresholds and request queue depth thresholds, the system can adjust its behavior based on operational conditions. This parameter change enables improved read QoS and reliability without requiring completely complex control logic, as the changes are based on measurable operational metrics.
2Reliability
If the memory device always completes the current operation before suspending (on-going mode), then the reliability is improved, but the suspend operation speed is reduced
Solution Approach 1:
The patent dynamically selects between cancel mode (faster suspend) and on-going mode (more reliable suspend) based on real-time operational conditions. When the number of suspend commands or request queue depth exceeds thresholds, the system chooses on-going mode to prioritize reliability. When conditions are favorable, it selects cancel mode to maximize speed. This dynamic selection resolves the contradiction by adapting the suspend behavior to current system state rather than using a fixed approach.
Solution Approach 2:
The patent introduces threshold parameters (suspend command count threshold, request queue depth threshold) that control the transition between different suspend behaviors. By monitoring these parameters and adjusting the suspend mode accordingly, the system can balance reliability and speed based on operational conditions. This parameter-based control enables the system to maintain high reliability when needed while preserving speed when conditions allow.
3Speed
If the memory device immediately suspends the current operation (cancel mode), then the suspend operation speed is improved, but the reliability is reduced due to interrupted program/erase operations
Solution Approach 1:
The patent implements dynamic mode selection where the memory controller evaluates current operational conditions and selects either cancel mode or on-going mode accordingly. When operational metrics indicate low risk (few suspend commands, shallow request queue), the system uses cancel mode for fast suspension. When metrics indicate high risk, it switches to on-going mode to ensure reliable completion. This dynamic approach resolves the contradiction by enabling fast suspension only when safety conditions are met.
Solution Approach 2:
The patent uses parameter thresholds to control the transition between cancel mode and on-going mode. By monitoring parameters such as the number of suspend commands and request queue depth, the system can determine when it is safe to use cancel mode for speed versus when to use on-going mode for reliability. This parameter-driven approach enables the system to optimize suspend speed while maintaining reliability through conditional logic based on measurable operational states.
Data Source
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AI summary
A memory controller is disclosed. The memory controller is configured to control the execution of a suspend operation by a memory device. The memory controller includes: a processor configured to output an operation control signal when the memory device is performing a program/erase operation; and a suspend operation manager configured to output suspend mode change information based on the operation control signal and suspend information, wherein the processor is further configured to control the memory controller such that the memory controller outputs a suspend mode change command and a suspend command based on the suspend mode change information.