MarginaliaSearch/code/libraries/array/cpp

LongArray C++ Helpers

This package contains helper functions for working with LongArray objects, as native C++ calls. The helpers are only built on Linux, and if they are absent, Java substitutes should be used instead.

Library loading and access is available through the NativeAlgos class.

Note that the C++ helpers are compiled with march=native by default, so they are not portable between different CPU architectures.

This provides a speedup for some operations, especially when compared to using MemorySegment's get methods and not Unsafe.

Benchmarks

JMH benchmark results for 64 bit quicksort N=2^10, 25 trials, graalvm 21.0.3:

Implementation	Throughput ops/s	Error p=99%
native	114.877	4.216
unsafe	98.443	2.723
memorysegment	72.492	1.980

Note that odds are stacked in favor of the native implementation since the dataset is fairly large, meaning the call overhead is less significant. For smaller datasets, the overhead of native calls may be a bigger factor.