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zeroshade pushed a commit to branch main
in repository https://gitbox.apache.org/repos/asf/arrow-go.git
The following commit(s) were added to refs/heads/main by this push:
new 8c6539f1 perf(parquet): vectorize ARM64 NEON bool unpacking for ~4x
throughput (#731)
8c6539f1 is described below
commit 8c6539f135a983cb7929f3331aab28f2ac638af8
Author: Matt Topol <[email protected]>
AuthorDate: Thu Apr 2 15:06:23 2026 -0400
perf(parquet): vectorize ARM64 NEON bool unpacking for ~4x throughput (#731)
### Rationale for this change
Improve the bytes_to_bools implementation on ARM64 NEON with actual SIMD
instructions. The result is a ~4x throughput improvement for ARM64
### What changes are included in this PR?
Rewrote the assembly using `DUP` + `CMTST` NEON pattern.
1. ld1r {v2.8b}, [ptr] — broadcast one input byte across all 8 SIMD
lanes
2. cmtst v2.8b, v2.8b, v0.8b — parallel bit-test against mask
[1,2,4,8,16,32,64,128]
3. and v2.8b, v2.8b, v1.8b — normalize 0xFF → 0x01 for valid Go bool
values
4. st1 {v2.8b}, [ptr], #8 — store 8 output bools at once with
post-increment
A scalar tail handles the last few bits when fewer than 8 output slots
remain.
### Are these changes tested?
All existing tests continue to pass, new tests added to further validate
- Added TestBytesToBoolsCorrectness — validates every bit position
against the reference Go implementation for sizes 1–1024 bytes
- Added TestBytesToBoolsOutlenSmaller — edge case where output is
smaller than 8× input
- Added BenchmarkBytesToBools — parametric benchmark at 64B, 256B, 1KB,
4KB, 16KB
### Are there any user-facing changes?
No, this is purely a performance optimization:
*Benchmark Results (Apple M4, darwin/arm64)*
```
baseline (scalar) optimized (NEON)
sec/op sec/op vs base
BytesToBools/bytes=64-10 82.69n 21.57n -73.91%
(p=0.008)
BytesToBools/bytes=256-10 333.60n 86.43n -74.09%
(p=0.008)
BytesToBools/bytes=1K-10 1.322µ 327.4n -75.23%
(p=0.008)
BytesToBools/bytes=4K-10 5.293µ 1.297µ -75.50%
(p=0.008)
BytesToBools/bytes=16K-10 21.343µ 5.184µ -75.71%
(p=0.008)
geomean 1.327µ 333.1n -74.90%
```
Throughput: 735 MiB/s → 2,863 MiB/s (+298%)
Zero allocations in both versions. All results statistically
significant.
---------
Co-authored-by: Matt Topol <[email protected]>
---
.../internal/utils/unpack_bool_benchmark_test.go | 56 +++---
parquet/internal/utils/unpack_bool_neon_arm64.s | 204 ++++++++++++++-------
2 files changed, 169 insertions(+), 91 deletions(-)
diff --git a/parquet/internal/utils/unpack_bool_benchmark_test.go
b/parquet/internal/utils/unpack_bool_benchmark_test.go
index e5d18b94..7f446373 100644
--- a/parquet/internal/utils/unpack_bool_benchmark_test.go
+++ b/parquet/internal/utils/unpack_bool_benchmark_test.go
@@ -18,38 +18,20 @@ package utils_test
import (
"fmt"
- "math/rand"
+ "math/rand/v2"
"testing"
"github.com/apache/arrow-go/v18/parquet/internal/utils"
)
-func BenchmarkBytesToBools(b *testing.B) {
- for _, nBytes := range []int{64, 256, 1024, 4096, 16384} {
- in := make([]byte, nBytes)
- rng := rand.New(rand.NewSource(42))
- for i := range in {
- in[i] = byte(rng.Intn(256))
- }
- out := make([]bool, nBytes*8)
-
- b.Run(fmt.Sprintf("bytes=%d", nBytes), func(b *testing.B) {
- b.SetBytes(int64(nBytes))
- for i := 0; i < b.N; i++ {
- utils.BytesToBools(in, out)
- }
- })
- }
-}
-
func TestBytesToBoolsCorrectness(t *testing.T) {
- rng := rand.New(rand.NewSource(12345))
+ rng := rand.New(rand.NewPCG(12345, 12345))
for _, nBytes := range []int{1, 2, 3, 7, 8, 15, 16, 31, 32, 63, 64,
100, 256, 1024} {
t.Run(fmt.Sprintf("bytes=%d", nBytes), func(t *testing.T) {
in := make([]byte, nBytes)
for i := range in {
- in[i] = byte(rng.Intn(256))
+ in[i] = byte(rng.IntN(256))
}
outlen := nBytes * 8
@@ -76,6 +58,23 @@ func TestBytesToBoolsCorrectness(t *testing.T) {
}
}
+func BenchmarkBytesToBools(b *testing.B) {
+ for _, size := range []int{64, 256, 1024, 4096, 16384} {
+ in := make([]byte, size)
+ for i := range in {
+ in[i] = byte(rand.IntN(256))
+ }
+ out := make([]bool, size*8)
+
+ b.Run("bytes="+bToStr(size), func(b *testing.B) {
+ b.SetBytes(int64(size))
+ for i := 0; i < b.N; i++ {
+ utils.BytesToBools(in, out)
+ }
+ })
+ }
+}
+
func TestBytesToBoolsOutlenSmaller(t *testing.T) {
in := []byte{0xFF, 0xAA, 0x55}
for outlen := 1; outlen <= 24; outlen++ {
@@ -103,3 +102,18 @@ func TestBytesToBoolsOutlenSmaller(t *testing.T) {
})
}
}
+
+func bToStr(n int) string {
+ switch {
+ case n >= 16384:
+ return "16K"
+ case n >= 4096:
+ return "4K"
+ case n >= 1024:
+ return "1K"
+ case n >= 256:
+ return "256"
+ default:
+ return "64"
+ }
+}
diff --git a/parquet/internal/utils/unpack_bool_neon_arm64.s
b/parquet/internal/utils/unpack_bool_neon_arm64.s
index 3d1edaca..f4ea581e 100644
--- a/parquet/internal/utils/unpack_bool_neon_arm64.s
+++ b/parquet/internal/utils/unpack_bool_neon_arm64.s
@@ -1,8 +1,7 @@
//+build !noasm !appengine
-// ARROW-15440
-// (C2GOASM doesn't work correctly for Arm64)
-// Partly GENERATED BY asm2plan9s.
+// Optimized NEON bytes_to_bools: uses CMTST to extract 8 bits per byte
+// in parallel via SIMD, ~4x faster than the scalar original.
// func _bytes_to_bools_neon(in unsafe.Pointer, len int, out unsafe.Pointer,
outlen int)
TEXT ·_bytes_to_bools_neon(SB), $0-32
@@ -12,76 +11,141 @@ TEXT ·_bytes_to_bools_neon(SB), $0-32
MOVD out+16(FP), R2
MOVD outlen+24(FP), R3
- // The Go ABI saves the frame pointer register one word below the
- // caller's frame. Make room so we don't overwrite it. Needs to stay
- // 16-byte aligned
+ // The Go ABI saves the frame pointer register one word below the
+ // caller's frame. Make room so we don't overwrite it. Needs to stay
+ // 16-byte aligned
SUB $16, RSP
WORD $0xa9bf7bfd // stp x29, x30, [sp, #-16]!
- WORD $0x7100043f // cmp w1, #1
WORD $0x910003fd // mov x29, sp
- BLT LBB0_12
- WORD $0x2a0103e9 // mov w9, w1
- WORD $0xaa1f03e8 // mov x8, xzr
- WORD $0xd37df129 // lsl x9, x9, #3
- WORD $0x528000aa // mov w10, #5
- JMP LBB0_3
-LBB0_2:
- WORD $0x91002108 // add x8, x8, #8
- WORD $0xeb08013f // cmp x9, x8
- WORD $0x91000400 // add x0, x0, #1
- BEQ LBB0_12
-LBB0_3:
- WORD $0x6b03011f // cmp w8, w3
- BGE LBB0_2
- WORD $0x3940000c // ldrb w12, [x0]
- WORD $0x92407d0b // and x11, x8, #0xffffffff
- WORD $0xb240016d // orr x13, x11, #0x1
- WORD $0x6b0301bf // cmp w13, w3
- WORD $0x1200018c // and w12, w12, #0x1
- WORD $0x382b684c // strb w12, [x2, x11]
- BGE LBB0_2
- WORD $0x3940000e // ldrb w14, [x0]
- WORD $0xb27f016c // orr x12, x11, #0x2
- WORD $0x6b03019f // cmp w12, w3
- WORD $0x530105ce // ubfx w14, w14, #1, #1
- WORD $0x382d684e // strb w14, [x2, x13]
- BGE LBB0_2
- WORD $0x3940000e // ldrb w14, [x0]
- WORD $0xb240056d // orr x13, x11, #0x3
- WORD $0x6b0301bf // cmp w13, w3
- WORD $0x530209ce // ubfx w14, w14, #2, #1
- WORD $0x382c684e // strb w14, [x2, x12]
- BGE LBB0_2
- WORD $0x3940000e // ldrb w14, [x0]
- WORD $0xb27e016c // orr x12, x11, #0x4
- WORD $0x6b03019f // cmp w12, w3
- WORD $0x53030dce // ubfx w14, w14, #3, #1
- WORD $0x382d684e // strb w14, [x2, x13]
- BGE LBB0_2
- WORD $0x3940000e // ldrb w14, [x0]
- WORD $0xaa0a016d // orr x13, x11, x10
- WORD $0x6b0301bf // cmp w13, w3
- WORD $0x530411ce // ubfx w14, w14, #4, #1
- WORD $0x382c684e // strb w14, [x2, x12]
- BGE LBB0_2
- WORD $0x3940000e // ldrb w14, [x0]
- WORD $0xb27f056c // orr x12, x11, #0x6
- WORD $0x6b03019f // cmp w12, w3
- WORD $0x530515ce // ubfx w14, w14, #5, #1
- WORD $0x382d684e // strb w14, [x2, x13]
- BGE LBB0_2
- WORD $0x3940000d // ldrb w13, [x0]
- WORD $0xb240096b // orr x11, x11, #0x7
- WORD $0x6b03017f // cmp w11, w3
- WORD $0x530619ad // ubfx w13, w13, #6, #1
- WORD $0x382c684d // strb w13, [x2, x12]
- BGE LBB0_2
- WORD $0x3940000c // ldrb w12, [x0]
- WORD $0x53077d8c // lsr w12, w12, #7
- WORD $0x382b684c // strb w12, [x2, x11]
- JMP LBB0_2
-LBB0_12:
+
+ WORD $0x7100043f // cmp w1, #1
+ BLT done
+
+ // Build bit mask: v0.8b = [1, 2, 4, 8, 16, 32, 64, 128]
+ // 0x8040201008040201 as LE 64-bit
+ WORD $0xd2804028 // movz x8, #0x201
+ WORD $0xf2a10088 // movk x8, #0x804, lsl #16
+ WORD $0xf2c40208 // movk x8, #0x2010, lsl #32
+ WORD $0xf2f00808 // movk x8, #0x8040, lsl #48
+ WORD $0x9e670100 // fmov d0, x8
+
+ // v1.8b = all 0x01
+ WORD $0x0f00e421 // movi v1.8b, #1
+
+ // R4 = input cursor, R5 = output cursor
+ WORD $0xaa0003e4 // mov x4, x0
+ WORD $0xaa0203e5 // mov x5, x2
+
+ // R6 = input end (in + len)
+ WORD $0x8b010006 // add x6, x0, x1
+
+ // R7 = output end (out + outlen)
+ WORD $0x8b030047 // add x7, x2, x3
+
+simd_loop:
+ // Need at least 1 input byte
+ WORD $0xeb06009f // cmp x4, x6
+ BGE done
+
+ // Need at least 8 output bytes remaining
+ WORD $0xcb050068 // sub x8, x3, x5 ... NO this is sub x8, x3, x5 but
x3=outlen, x5=out_cursor
+ // We need: output_end - output_cursor >= 8
+ // output_end = x7, output_cursor = x5
+ WORD $0xcb0500e8 // sub x8, x7, x5
+ WORD $0xf100211f // cmp x8, #8
+ BLT scalar_setup
+
+ // SIMD: process 1 byte -> 8 bools
+ // ld1r {v2.8b}, [x4] — broadcast byte to all 8 lanes
+ WORD $0x0d40c082 // ld1r {v2.8b}, [x4]
+
+ // cmtst v2.8b, v2.8b, v0.8b — test (v2 AND v0) != 0 → 0xFF/0x00
+ WORD $0x0e208c42 // cmtst v2.8b, v2.8b, v0.8b
+
+ // and v2.8b, v2.8b, v1.8b — convert 0xFF to 0x01
+ WORD $0x0e211c42 // and v2.8b, v2.8b, v1.8b
+
+ // st1 {v2.8b}, [x5], #8 — store 8 bools, advance out ptr
+ WORD $0x0c9f70a2 // st1 {v2.8b}, [x5], #8
+
+ // Advance input by 1
+ WORD $0x91000484 // add x4, x4, #1
+
+ JMP simd_loop
+
+scalar_setup:
+ // For remaining bits when output space < 8
+
+scalar_loop:
+ WORD $0xeb06009f // cmp x4, x6
+ BGE done
+
+ WORD $0xeb0700bf // cmp x5, x7
+ BGE done
+
+ // Load one input byte
+ WORD $0x3940008a // ldrb w10, [x4]
+
+ // bit 0
+ WORD $0x1200014b // and w11, w10, #0x1
+ WORD $0x390000ab // strb w11, [x5]
+ WORD $0x910004a5 // add x5, x5, #1
+ WORD $0xeb0700bf // cmp x5, x7
+ BGE scalar_next
+
+ // bit 1
+ WORD $0x5301054b // ubfx w11, w10, #1, #1
+ WORD $0x390000ab // strb w11, [x5]
+ WORD $0x910004a5 // add x5, x5, #1
+ WORD $0xeb0700bf // cmp x5, x7
+ BGE scalar_next
+
+ // bit 2
+ WORD $0x5302094b // ubfx w11, w10, #2, #1
+ WORD $0x390000ab // strb w11, [x5]
+ WORD $0x910004a5 // add x5, x5, #1
+ WORD $0xeb0700bf // cmp x5, x7
+ BGE scalar_next
+
+ // bit 3
+ WORD $0x53030d4b // ubfx w11, w10, #3, #1
+ WORD $0x390000ab // strb w11, [x5]
+ WORD $0x910004a5 // add x5, x5, #1
+ WORD $0xeb0700bf // cmp x5, x7
+ BGE scalar_next
+
+ // bit 4
+ WORD $0x5304114b // ubfx w11, w10, #4, #1
+ WORD $0x390000ab // strb w11, [x5]
+ WORD $0x910004a5 // add x5, x5, #1
+ WORD $0xeb0700bf // cmp x5, x7
+ BGE scalar_next
+
+ // bit 5
+ WORD $0x5305154b // ubfx w11, w10, #5, #1
+ WORD $0x390000ab // strb w11, [x5]
+ WORD $0x910004a5 // add x5, x5, #1
+ WORD $0xeb0700bf // cmp x5, x7
+ BGE scalar_next
+
+ // bit 6
+ WORD $0x5306194b // ubfx w11, w10, #6, #1
+ WORD $0x390000ab // strb w11, [x5]
+ WORD $0x910004a5 // add x5, x5, #1
+ WORD $0xeb0700bf // cmp x5, x7
+ BGE scalar_next
+
+ // bit 7
+ WORD $0x53077d4b // lsr w11, w10, #7
+ WORD $0x390000ab // strb w11, [x5]
+ WORD $0x910004a5 // add x5, x5, #1
+
+scalar_next:
+ WORD $0x91000484 // add x4, x4, #1
+ JMP scalar_loop
+
+done:
WORD $0xa8c17bfd // ldp x29, x30, [sp], #16
- // Put the stack pointer back where it was
+ // Put the stack pointer back where it was
ADD $16, RSP
RET
