MarginaliaSearch/code/libraries/array/cpp
Viktor Lofgren 9e766bc056 (array) Clean up search function jungle
Retire search functions that weren't used, including the native implementations.  Drop confusing suffixes on search function names.  Search functions no longer encode search misses as negative values.

Replaced binary search function with a branchless version that is much faster.

Cleaned up benchmark code.
2024-05-17 14:30:06 +02:00
..
java/nu/marginalia (array) Clean up search function jungle 2024-05-17 14:30:06 +02:00
resources (array, experimental) Call C++ helper methods to do some low level stuff a bit faster than is possible with Java 2024-05-14 12:54:14 +02:00
src/main (array) Clean up search function jungle 2024-05-17 14:30:06 +02:00
build.gradle (array) Clean up native code a bit 2024-05-16 14:47:10 +02:00
compile.sh (array) Clean up native code a bit 2024-05-16 14:47:10 +02:00
readme.md (array, experimental) Add benchmark results for quicksort 2024-05-14 18:15:30 +02:00

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.