Java Array Copy Elimination via Length Parameter Modification
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Solution Overview
Problem
Array copying operations in Java Virtual Machines are time-expensive due to memory bandwidth limitations, particularly in high-performance computer hardware systems, and existing optimizations fail to adequately address these issues, especially in scenarios like JDBC drivers converting network bytes to strings.
Innovation Solution
A system and method that uses a compiler to perform static analysis and replace array copies with array reuse and potential length reduction by reusing the source array as the target array, modifying the generated machine code to eliminate unnecessary copies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If array copy operations are used to increase or decrease array size, then array size can be changed, but memory bandwidth is consumed and performance deteriorates
Solution Approach 1:
The invention changes the length parameter of the source array in-place to match the target array length, avoiding the need to allocate a new array and copy data. This is achieved by modifying the array's length field directly when the source and target arrays are the same object, thereby adapting the array size without consuming memory bandwidth for copying operations.
2Adaptability or versatility
If array copy operations are performed, then array size can be adjusted, but time consumption increases
Solution Approach 1:
The invention directly modifies the length parameter of the array in-place rather than performing a copy operation. By changing the length field of the source array to match the desired target length, the invention achieves array size adjustment instantly without the time-consuming data copying process, while maintaining the same array object in memory.
3Adaptability or versatility
If new arrays are allocated for size changes, then array size can be modified, but memory allocation overhead increases
Solution Approach 1:
The invention modifies the length parameter of the existing source array in-place to match the target array length, eliminating the need to allocate a new array. This approach reduces memory allocation overhead and simplifies the operation from involving multiple steps (allocation, copying, assignment) to a single parameter modification, thereby reducing device complexity.
Data Source
AI summary
A system and method for removal of array copies in Java by reusing a source array for the target array and potentially cutting the length of the source array. In accordance with an embodiment, the system comprises physical computers or similar computing devices; a computing or virtual execution environment; a virtual machine that includes a compiler and memory spaces for Java application bytecode and storage for generated machine code; and wherein the compiler performs a static analysis of the code wherever any array copy is found, and determines if the array copy can be replaced with a reuse of the source array as the target array, potentially followed by a cut operation, and if so modifies the generated machine code accordingly.