Memory Controller Garbage Collection Timing Based on Write Command Groups

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Solution Overview

Problem

Conventional memory systems experience delayed command processing and degraded write performance due to garbage collection, which can lead to insufficient free memory blocks, especially when handling a high workload of write commands.

Innovation Solution

A memory system and controller that determine the timing for garbage collection based on a write command group's transmission time and data size information, stored in an entry buffer, to dynamically adjust the garbage collection time and secure free memory blocks, thereby minimizing delays and maintaining stable write performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If garbage collection is performed to secure free memory blocks, then the number of free memory blocks is increased, but command processing is delayed and write performance is degraded

Engineering Contradiction:

Improvenumber of free memory blocksVSAvoidcommand processing delay

Core Design Contradiction:

Quantity of substanceVSLoss of time

Solution Approach 1:

The memory controller performs garbage collection in advance before the number of free memory blocks becomes insufficient. By monitoring the count of free blocks and proactively executing GC operations, the system secures free blocks before they are critically depleted, preventing command processing delays while maintaining adequate free block availability.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The memory controller dynamically adjusts garbage collection operations based on real-time workload conditions and free block counts. When write commands are queued and free blocks are sufficient, GC is performed; when free blocks are low or workload is high, GC timing is adjusted. This dynamic adaptation resolves the contradiction by making GC execution conditional rather than fixed.

Inventive Principle:

Principle #15Dynamics

2Quantity of substance

If garbage collection is performed frequently to maintain free memory blocks, then free block availability is improved, but write performance is degraded due to continuous GC operations

Engineering Contradiction:

Improvefree memory block availabilityVSAvoidwrite performance

Core Design Contradiction:

Quantity of substanceVSProductivity

Solution Approach 1:

The memory controller performs garbage collection partially - only when specific conditions are met (free block count above threshold, write commands queued in buffer). Rather than continuously or excessively performing GC, the controller applies GC selectively based on monitored parameters, achieving sufficient free block availability without overdoing GC operations that would harm write performance.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The memory controller implements feedback mechanisms by continuously monitoring the number of free memory blocks and the state of command buffers. Based on this feedback, the controller intelligently decides when to initiate garbage collection - only when free blocks are adequate and work can be deferred. This feedback-driven approach balances free block maintenance with write performance preservation.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11061815B2Memory system, memory controller and operating method

Publication Date: 2021.07.13 MIMIRIP LLC

AI summary

A memory system, a memory controller and an operating method are disclosed. By determining a time for garbage collection, based on information for a write command group including a plurality of write commands inputted from a host, it is possible to minimize a time in which processing a command transmitted from the host is delayed due to garbage collection, and ensure stable write performance.