JDK-8150313 : aarch64: optimise array copy using SIMD instructions
- Type: Enhancement
- Component: hotspot
- Sub-Component: compiler
- Affected Version: 9
- Priority: P4
- Status: Resolved
- Resolution: Fixed
- OS: linux
- CPU: aarch64
- Submitted: 2016-02-20
- Updated: 2021-02-01
- Resolved: 2016-03-08
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| JDK 9 | Other |
|---|---|
9 b112Fixed  |
openjdk8u292Fixed |
Related Reports
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Relates :
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Description
This uses SIMD ldp/stp Qx, Qy instructions instead of scalar ldp/stp instructions, thereby loading/storing 32 bytes at a time instead of 16. It also extends the small copy code to copy 0-96 instead of 0-80 (because 80 is not divisible by 32). This improves performance on some micro-arches and not on others so I have provided a -XX:+UseSIMDForMemoryOps switch which defaults to false (we could look at enabling this by default for micro-arches where we know SIMD is better).