Multi-Stage Garbage Collector for Adaptive Heap Management

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Solution Overview

Problem

Existing garbage collection methods in computing systems face inefficiencies, particularly in managing heap size stages, leading to unpredictable performance and potential memory issues due to the inability to adaptively adjust garbage collection strategies based on dynamic heap conditions.

Innovation Solution

Implementing multiple garbage collection strategies, including concurrent non-compacting garbage collection, which distinguishes between heap size growth and stable stages, using dynamically tunable parameters and closed-loop feedback to optimize memory management, allowing for adaptive garbage collection based on free space ratios and performance goals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single garbage collection strategy is used for all heap conditions, then the garbage collection mechanism is simple to implement, but performance becomes unpredictable and memory management efficiency deteriorates

Engineering Contradiction:
Improveperformance predictabilityVSAvoidgarbage collection mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements dynamic garbage collection by switching between different GC strategies (incremental GC, concurrent GC, compacting GC) based on the current heap size stage. The system monitors heap usage and automatically selects the appropriate GC algorithm, making the garbage collection mechanism adaptive rather than static. This resolves the contradiction by improving performance predictability through context-aware strategy selection while managing complexity through automated decision-making.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the operational parameters of garbage collection based on heap conditions. When the heap is in growth stage, one set of GC parameters is used; when stable, different parameters are applied. This allows the system to optimize for different phases of memory usage, improving overall reliability without requiring a completely different system architecture.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If adaptive garbage collection strategies are implemented for different heap stages, then memory management efficiency improves, but system complexity increases

Engineering Contradiction:
Improvememory management efficiencyVSAvoidgarbage collection system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the heap lifecycle into distinct stages (growth stage and stable stage) and applies different garbage collection strategies to each segment. This segmentation allows optimized handling for each phase - using incremental GC during growth to minimize overhead, and compacting GC during stable phases to maximize memory utilization. The segmentation approach improves productivity by tailoring GC behavior to specific heap conditions while keeping the overall system manageable through clear stage boundaries.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system implements feedback mechanisms to monitor heap size and usage patterns, then uses this information to dynamically adjust garbage collection strategy. The feedback loop continuously evaluates heap conditions and selects appropriate GC algorithms, improving memory management efficiency through data-driven decisions while automating the complexity management process.

Inventive Principle:
Principle #23Feedback

3Ease of operation

If multiple garbage collection algorithms are used concurrently, then responsiveness during GC operations improves, but implementation complexity and resource overhead increase

Engineering Contradiction:
Improveapplication responsiveness during GCVSAvoidmultiple GC algorithms implementation
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent dynamically selects which garbage collection algorithm to execute based on the current heap stage and system conditions. Rather than running multiple algorithms simultaneously or requiring manual selection, the system automatically transitions between incremental GC, concurrent GC, and compacting GC based on real-time heap metrics. This dynamic approach maintains application responsiveness by choosing the most appropriate algorithm for each situation while avoiding the complexity of managing all algorithms concurrently.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3577567B1Multiple stage garbage collector
Publication Date: 2024.10.23 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP3577567B1 patent drawingFigure 1
  • EP3577567B1 patent drawingFigure 2~3
  • EP3577567B1 patent drawingFigure 4~5

AI summary

A method for use with a garbage collector to provide different garbage collections is disclosed. The garbage collections are concurrent garbage collection provided in a dedicated thread concurrently running in a computing device with a mutator thread. A heap size stage, from multiple heap size stages including a heap size growth stage and a heap size stable stage, is determined from a free space amount subsequent a garbage collection. A heap stable garbage collection is applied in response to the heap size stage being the heap size stable stage. A heap growth garbage collection is applied in response to the heap size stage being the heap size growth stage.