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Refactor ZSTD_row_getMatchMask for RVV optimization

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Performance (vs. SWAR)
- 16-byte data: 5.87x speedup
- 32-byte data: 9.63x speedup
- 64-byte data: 17.98x speedup

Co-authored-by: gong-flying <gongxiaofei24@iscas.ac.cn>
This commit is contained in:
w1m024
2025-09-11 20:45:54 +00:00
co-authored by gong-flying
parent c9d2cbd5ba
commit fb7a86f20f
1 changed files with 23 additions and 21 deletions
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lib/compress/zstd_lazy.c
+23 -21
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@@ -1054,30 +1054,32 @@ ZSTD_row_getNEONMask(const U32 rowEntries, const BYTE* const src, const BYTE tag
FORCE_INLINE_TEMPLATE ZSTD_VecMask
ZSTD_row_getRVVMask(int nbChunks, const BYTE* const src, const BYTE tag, const U32 head)
{
U16 matches[4] = {0};
int i;
assert(nbChunks == 1 || nbChunks == 2 || nbChunks == 4);
ZSTD_VecMask matches;
size_t vl;
size_t vl = __riscv_vsetvl_e8m1(16);
if (rowEntries == 16) {
vl = __riscv_vsetvl_e8m1(16);
vuint8m1_t chunk = __riscv_vle8_v_u8m1(src, vl);
vbool8_t mask = __riscv_vmseq_vx_u8m1_b8(chunk, tag, vl);
vuint16m1_t mask_u16 = __riscv_vreinterpret_v_b8_u16m1(mask);
matches = __riscv_vmv_x_s_u16m1_u16(mask_u16);
return ZSTD_rotateRight_U16((U16)matches, head);
for (i = 0; i < nbChunks; i++) {
vuint8m1_t chunk = __riscv_vle8_v_u8m1((const uint8_t*)(src + 16 * i), vl);
vbool8_t equalMask = __riscv_vmseq_vx_u8m1_b8(chunk, tag, vl);
size_t vl_w = __riscv_vsetvl_e16m2(16);
vuint16m2_t one = __riscv_vmv_v_x_u16m2(1, vl_w);
vuint16m2_t indices = __riscv_vid_v_u16m2(vl_w);
vuint16m2_t powers_of_2 = __riscv_vsll_vv_u16m2(one, indices, vl_w);
vuint16m2_t zero = __riscv_vmv_v_x_u16m2(0, vl_w);
vuint16m2_t selected_bits = __riscv_vmerge_vvm_u16m2(zero, powers_of_2, equalMask, vl_w);
vuint16m1_t reduction = __riscv_vredor_vs_u16m2_u16m1(selected_bits, __riscv_vmv_s_x_u16m1(0, vl_w), vl_w);
matches[i] = __riscv_vmv_x_s_u16m1_u16(reduction);
} else if (rowEntries == 32) {
vl = __riscv_vsetvl_e8m2(32);
vuint8m2_t chunk = __riscv_vle8_v_u8m2(src, vl);
vbool4_t mask = __riscv_vmseq_vx_u8m2_b4(chunk, tag, vl);
vuint32m1_t mask_u32 = __riscv_vreinterpret_v_b4_u32m1(mask);
matches = __riscv_vmv_x_s_u32m1_u32(mask_u32);
return ZSTD_rotateRight_U32((U32)matches, head);
} else { // rowEntries = 64
vl = __riscv_vsetvl_e8m4(64);
vuint8m4_t chunk = __riscv_vle8_v_u8m4(src, vl);
vbool2_t mask = __riscv_vmseq_vx_u8m4_b2(chunk, tag, vl);
vuint64m1_t mask_u64 = __riscv_vreinterpret_v_b2_u64m1(mask);
matches = __riscv_vmv_x_s_u64m1_u64(mask_u64);
return ZSTD_rotateRight_U64(matches, head);
}
if (nbChunks == 1) return ZSTD_rotateRight_U16(matches[0], head);
if (nbChunks == 2) return ZSTD_rotateRight_U32((U32)matches[1] << 16 | (U32)matches[0], head);
assert(nbChunks == 4);
return ZSTD_rotateRight_U64((U64)matches[3] << 48 | (U64)matches[2] << 32 | (U64)matches[1] << 16 | (U64)matches[0], head);
}
#endif