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eclipse-openj9 / openj9

Eclipse OpenJ9: A Java Virtual Machine for OpenJDK that's optimized for small footprint, fast start-up, and high throughput. Builds on Eclipse OMR (https://github.com/eclipse/omr) and combines with the Extensions for OpenJDK for OpenJ9 repo.
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Inlining support of MultiANewArray for 2 dimensional arrays on P/Z/AArch64 #2424

Open yanluo7 opened 6 years ago

yanluo7 commented 6 years ago

Support inlining of 2 dimensional reference arrays where the second dimension is 0. The inlining sequence allocates N+1 array objects (N being the length of first dimension): 1 "large" array of length N and N "small" arrays of length 0; and the elements of the "large" array of length N point to their respective "small" arrays to form the two dimensions.

Performance implication: We observed in benchmarks a large number of multi-dimension array allocations. Further investigation shows much of these are 2-dimensional, and the second dimension is 0. Inlining of these types of arrays would be beneficial as no helper calls would be needed. We observed day trade throughout to improved by ~0.5%.

Support for X implemented in https://github.com/eclipse/openj9/pull/2408

andrewcraik commented 6 years ago

@fjeremic @gita-omr FYI

fjeremic commented 3 years ago

Implemented on Z in #11088.