Multiobject Garbage Collection for Memory Bandwidth Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current garbage collection techniques face inefficiencies in managing large multi-threaded applications with vast memory heaps and power-constrained devices, particularly in detecting and collecting garbage cycles spanning multiple regions, which leads to high memory bandwidth requirements and power consumption.
Innovation Solution
The approach organizes objects into larger groups called multiobjects, maintaining remembered sets between them instead of individual objects, allowing for efficient copying and garbage cycle detection without object-level tracing, and reducing memory access and power usage by using multiobject-level transitive closure computation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If object-level tracing is used to detect garbage cycles spanning multiple regions, then garbage collection accuracy is improved, but memory bandwidth requirements and power consumption increase significantly
Solution Approach 1:
The patent segments the heap into multiple independently collectable regions and groups individual objects into multiobjects. By maintaining remembered sets at the multiobject level rather than individual object level, the system reduces the volume of data that must be traced during garbage collection, thereby reducing memory bandwidth requirements and power consumption while still accurately detecting garbage cycles spanning multiple regions.
2Measurement precision
If individual objects are tracked separately in remembered sets, then reference tracking precision is improved, but memory overhead and collection overhead increase
Solution Approach 1:
The patent merges multiple individual objects into multiobjects and maintains a single remembered set entry per multiobject rather than per individual object. This consolidation reduces the size of remembered sets and decreases the overhead associated with tracking references during garbage collection, while still maintaining sufficient precision to identify garbage cycles.
3Productivity
If parallel copying collector is used to copy heap objects, then collection speed is improved, but memory bandwidth requirements increase
Solution Approach 1:
The patent divides the heap into multiple independently collectable regions and processes them in parallel. By copying entire multiobjects as units rather than individual objects, the system reduces the total number of memory copy operations required, thereby reducing memory bandwidth consumption while maintaining high collection throughput through parallel processing of multiple regions.
4Measurement precision
If global snapshot-at-the-beginning tracing is performed concurrently with mutators, then garbage cycle detection accuracy is improved, but pause times and mutator interference increase
Solution Approach 1:
The patent segments the tracing process into region-level operations rather than requiring a global snapshot of all objects. By performing tracing at the multiobject level and processing multiple regions in parallel, the system achieves accurate garbage cycle detection with shorter pause times and reduced interference with mutator operations.
Data Source
AI summary
Computer system, method and article of manufacture for garbage collection in computer systems that combines individual objects into linearized trees called multiobjects and thereafter utilizes multiobjects to implement most memory management operations such as detection of dead objects and compaction without the need to inspect individual objects, thereby improving performance and reducing power consumption.