Dynamic Garbage Collection Algorithm Selection for Heap Regions

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Solution Overview

Problem

Current garbage collection algorithms in languages like Java are static and do not adapt to the dynamic nature of heap regions, leading to inefficiencies as they treat all objects uniformly, regardless of their lifespan or type, resulting in suboptimal performance.

Innovation Solution

A system and method that dynamically selects a garbage collection algorithm based on the contents of heap regions by instrumenting software applications to allocate objects into specific regions and scanning object statistics to determine the appropriate algorithm for each region, allowing for the use of different algorithms for movable, non-movable, short-lived, or long-lived objects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a static garbage collection algorithm is used for all heap regions, then the system is simple to implement and manage, but performance is suboptimal because it cannot adapt to different object types and lifecycles

Engineering Contradiction:
Improvegarbage collection performanceVSAvoidgarbage collection system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The heap is divided into multiple regions, with each region dedicated to specific object types or lifecycle categories (e.g., short-lived objects, long-lived objects, movable objects, non-movable objects). This segmentation allows different garbage collection algorithms to be applied to different regions based on their specific characteristics, optimizing performance for each category while maintaining manageable system complexity through modular organization.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system dynamically selects appropriate garbage collection algorithms for each heap region based on the objects contained within them. Rather than using a fixed algorithm for the entire heap, the system adapts its behavior by examining object characteristics and applying the most suitable collection strategy (e.g., copying, mark-sweep, reference counting) to each region, thereby improving overall performance without requiring complete system redesign.

Inventive Principle:
Principle #15Dynamics

2Productivity

If different garbage collection algorithms are used for different heap regions, then performance is optimized for specific object types, but the system complexity increases due to multiple algorithms and selection logic

Engineering Contradiction:
Improveapplication throughputVSAvoidalgorithm selection complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

Objects are pre-categorized and placed into appropriate heap regions during allocation based on their type and expected lifecycle characteristics. This preliminary classification is performed through instrumentation of software applications that allocate objects, allowing the garbage collection system to automatically apply the correct algorithm without requiring complex runtime analysis or manual configuration during garbage collection events.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system automatically determines which garbage collection algorithm to apply to each heap region by examining the objects contained within them. Rather than requiring external configuration or complex selection logic, the garbage collection system self-adapts by analyzing object characteristics and selecting appropriate algorithms, thereby reducing the burden on application developers and simplifying system management.

Inventive Principle:
Principle #25Self-service

3Loss of time

If all objects are treated uniformly during garbage collection, then the collection process is simple and fast, but memory fragmentation increases and pause times are longer

Engineering Contradiction:
Improvegarbage collection pause timeVSAvoidregion-based collection complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

Different garbage collection strategies are applied to different heap regions based on the specific characteristics of objects within each region. For example, regions containing short-lived objects may use copying collection for rapid reclamation, while regions with long-lived objects may use mark-sweep to minimize pause times. This localized approach optimizes performance for each region's specific needs rather than applying a one-size-fits-all solution.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system changes the garbage collection parameters and algorithm selection based on the contents of each heap region. By examining object statistics such as lifespan, size, and mobility characteristics, the system dynamically adjusts which collection algorithm is applied to each region, thereby reducing overall pause times and minimizing memory fragmentation through region-specific optimization.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4012568A1System and method for dynamically selecting a garbage collection algorithm based on the contents of heap regions
Publication Date: 2022.06.15 ORACLE INT CORP
  • EP4012568A1 patent drawingFigure 1
  • EP4012568A1 patent drawingFigure 2
  • EP4012568A1 patent drawingFigure 3

AI summary

A system and method for dynamically selecting a garbage collection algorithm based on the contents of heap regions. In accordance with an embodiment, a software application can be instrumented so that the system can place software objects allocated by the application, or by different parts of the application, into different regions of the heap. When garbage collection is invoked, the system can scan the heap, examine object statistics to determine if particular objects are, e.g., short-lived, long-lived, or some other type of object, and then use this information to determine which garbage collection algorithm to use with particular heap regions. In accordance with an embodiment, the system can identify regions as containing particular object types, for example, movable or non-movable object types, or object liveness, and use different garbage collection algorithms accordingly. Different garbage collection algorithms can be used with different regions, based on their content at a particular time.