Compile-Time Memory Allocation Folding for Garbage Collection Overhead
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Solution Overview
Problem
Automatic memory management systems, particularly those using garbage collection, incur significant overhead due to memory allocation operations and write barriers, which can impact application performance and user experience, especially in low-pause-time garbage collectors.
Innovation Solution
A compiler-based approach that folds multiple memory allocation instructions into a single operation at compile-time, eliminating the need for write barriers by ensuring memory allocations are contiguous and reducing garbage collection triggers, thereby minimizing runtime overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple memory allocation operations are performed separately at runtime, then memory can be allocated dynamically as needed, but memory allocation overhead increases and write barriers are required
Solution Approach 1:
The patent combines multiple separate memory allocation operations into a single folded allocation instruction at compile-time. This merging eliminates redundant allocation overhead and removes the need for multiple write barriers, directly improving application throughput while reducing time loss.
Solution Approach 2:
The patent performs memory allocation folding during the compile-time phase rather than at runtime. By preliminarily analyzing and combining allocation instructions before execution, the system eliminates runtime overhead and write barriers, improving both productivity and reducing time loss.
2Reliability
If write barriers are implemented with multiple instructions to track inter-generational pointers, then garbage collection correctness is maintained, but allocation overhead increases
Solution Approach 1:
The patent extracts and removes write barrier instructions from the compiled code by folding allocations at compile-time. Since folded allocations create contiguous memory regions with single ownership, the complex write barrier mechanism becomes unnecessary, reducing device complexity while maintaining garbage collection correctness through alternative means.
Solution Approach 2:
The patent creates temporary folded allocation regions that exist only during specific execution paths. These short-lived folded allocations eliminate the need for persistent write barrier infrastructure, reducing overall system complexity while maintaining correctness where needed.
3Ease of manufacture
If memory allocations are performed separately in different code blocks, then code modularity is maintained, but allocation overhead accumulates and write barriers are needed
Solution Approach 1:
The patent introduces a compile-time dimension for analyzing and folding allocation instructions across different code blocks. By operating in this temporal dimension before runtime, the system can combine allocations from modular code blocks without sacrificing modularity, thereby improving throughput without penalizing code organization.
Data Source
AI summary
A computer-implemented method for compilation of applications can include receiving a set of software instructions and traversing the set of software instructions based on a control-flow order of the set of software instructions. The traversing can include identifying a first allocation instruction in the set of software instructions, the first allocation instruction being configured to allocate a first amount of memory for a first object and identifying a second allocation instruction in the set of software instructions, the second allocation instruction being configured to allocate a second amount of memory for a second object. The method can include determining that the first allocation instruction dominates the second allocation instruction and, in response to the determining, combining the first allocation instruction and the second allocation instruction into a folded allocation instruction that allocates the first amount of memory and the second amount of memory in a single memory allocation operation.