Persistent Memory Background Eviction for Low-Latency Flush

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Solution Overview

Problem

Existing memory systems face high latency and energy consumption during data transfer from volatile to persistent storage, leading to increased system costs and limited storage capacity.

Innovation Solution

Implement a persistent memory controller with metadata management and a weighted round-robin selection process for data eviction, utilizing device idle time to perform background flush, thereby reducing latency and energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If data is moved from volatile memory to persistent storage immediately, then data persistence is ensured, but system latency increases and energy consumption rises

Engineering Contradiction:
Improvedata persistenceVSAvoidsystem latency
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary actions by identifying and prioritizing dirty data in advance using metadata tracking (access patterns, age, hotness), then executes flush operations during idle periods. This preliminary identification allows the system to ensure data persistence without immediate full flush, reducing latency while maintaining reliability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The memory controller autonomously manages data eviction by monitoring its own idle time and automatically initiating flush operations without external intervention. The system uses its own idle periods to perform background eviction, eliminating the need for host-initiated flush commands and reducing system latency.

Inventive Principle:
Principle #25Self-service

2Quantity of substance

If large amounts of data are moved to persistent storage, then storage capacity is utilized, but energy consumption increases

Engineering Contradiction:
Improvedata transfer volumeVSAvoidenergy consumption
Core Design Contradiction:
Quantity of substanceVSUse of energy by moving object

Solution Approach 1:

Instead of flushing all dirty data immediately, the system performs partial flushes by prioritizing critical data (based on metadata such as access frequency and age) and leaving less critical data for later. This partial action approach reduces energy consumption per operation while ensuring essential data persistence.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The system uses periodic idle time detection to trigger batched flush operations. By accumulating flush operations during idle periods and executing them periodically rather than continuously, the system reduces peak energy consumption while maintaining data persistence requirements.

Inventive Principle:
Principle #19Periodic action

3Productivity

If data eviction is performed during active operations, then memory management efficiency improves, but system latency and communication delays increase

Engineering Contradiction:
Improvememory management efficiencyVSAvoidcommunication delay
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The system extracts the data eviction function from the critical data path by implementing background eviction that operates independently during idle periods. This separation allows memory management to proceed efficiently without blocking host communications, as eviction operations are performed in parallel during non-critical times.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The metadata controller acts as an intermediary that tracks data characteristics and priorities without directly interfering with host memory operations. This intermediary layer enables efficient memory management decisions to be made based on metadata analysis, while actual data movement occurs during idle periods without impacting communication latency.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4586099B1Memory management based on background eviction
Publication Date: 2025.12.24 SAMSUNG ELECTRONICS CO LTD
  • EP4586099B1 patent drawingFigure 1
  • EP4586099B1 patent drawingFigure 2
  • EP4586099B1 patent drawingFigure 3

AI summary

Provided are systems (300), methods, and apparatuses for low latency global persistent flush based on background eviction. In one or more examples, the systems (300), devices (325), and methods include generating metadata based on monitoring data in volatile memory (370), generating a request to remove the data in the volatile memory (370) based on the metadata, and processing the request based on the request being allowed to proceed to a data controller (355) in response to a granting of the request based on a request criterion.