kwanCCC / sorted-rs

check sequence is sorted or not but through SIMD

Another algorithm base on SIMD which use to check slice is sorted or not

It both support SSE2 and AVX2 and much faster than regular implementations.

generic

 [ a, b, c, d .... x, y, z]
 compare a and b,
 compare b and c,
 compare c and d

SIMD

 [ a, b, c, d .... x, y, z]
 load [a, b, c, d] into chunk0,
 load [b, c, d, d] into chunk1,
 compare chunk0 and chunk1,
 load [d, e, f, g] into chunk0,
 load [e, f, g, g] into chunk1,
 compare chunk0 and chunk1 again

Benchmark on AMD

size	generic	sse	avx2
4	7.4974 ns	8.3876 ns	1.1984 ns
32	65.302 ns	40.632 ns	16.469 ns
64	121.92 ns	71.861 ns	30.551 ns
128	237.09 ns	144.08 ns	66.191 ns
256	466.77 ns	273.48 ns	99.640 ns
1024	1.8486 µs	1.0634 µs	410.66 ns
4096	7.3648 µs	4.2080 µs	6.1038 µs
16384	29.458 µs	16.702 µs	6.1038 µs
65536	117.82 µs	66.982 µs	24.355 µs