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Improve speed of ZSTD_compressSequencesAndLiterals() using RVV

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This commit is contained in:
李子建
2025-06-02 17:21:02 +08:00
committed by Zijian Li
parent f9938c217d
commit d95123f2e6
2 changed files with 157 additions and 0 deletions
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lib/common/compiler.h
+6
View File
@@ -218,6 +218,9 @@
# if defined(__ARM_NEON) || defined(_M_ARM64)
# define ZSTD_ARCH_ARM_NEON
# endif
# if defined(__riscv) && defined(__riscv_vector)
# define ZSTD_ARCH_RISCV_RVV
# endif
#
# if defined(ZSTD_ARCH_X86_AVX2)
# include <immintrin.h>
@@ -227,6 +230,9 @@
# elif defined(ZSTD_ARCH_ARM_NEON)
# include <arm_neon.h>
# endif
# if defined(ZSTD_ARCH_RISCV_RVV)
# include <riscv_vector.h>
# endif
#endif
/* C-language Attributes are added in C23. */
lib/compress/zstd_compress.c
+151
View File
@@ -7284,6 +7284,93 @@ static size_t convertSequences_noRepcodes(
return longLen;
}
#elif defined ZSTD_ARCH_RISCV_RVV
#include <riscv_vector.h>
/*
* Convert `vl` sequences per iteration, using AVX2 intrinsics:
* - offset -> offBase = offset + 2
* - litLength -> (U16) litLength
* - matchLength -> (U16)(matchLength - 3)
* - rep is ignored
* Store only 8 bytes per SeqDef (offBase[4], litLength[2], mlBase[2]).
*
* @returns 0 on succes, with no long length detected
* @returns > 0 if there is one long length (> 65535),
* indicating the position, and type.
*/
static size_t convertSequences_noRepcodes(SeqDef* dstSeqs, const ZSTD_Sequence* inSeqs, size_t nbSequences) {
size_t longLen = 0;
/* RVV depends on the specific definition of target structures */
ZSTD_STATIC_ASSERT(sizeof(ZSTD_Sequence) == 16);
ZSTD_STATIC_ASSERT(offsetof(ZSTD_Sequence, offset) == 0);
ZSTD_STATIC_ASSERT(offsetof(ZSTD_Sequence, litLength) == 4);
ZSTD_STATIC_ASSERT(offsetof(ZSTD_Sequence, matchLength) == 8);
ZSTD_STATIC_ASSERT(sizeof(SeqDef) == 8);
ZSTD_STATIC_ASSERT(offsetof(SeqDef, offBase) == 0);
ZSTD_STATIC_ASSERT(offsetof(SeqDef, litLength) == 4);
ZSTD_STATIC_ASSERT(offsetof(SeqDef, mlBase) == 6);
size_t vl = 0;
for (size_t i = 0; i < nbSequences; i += vl) {
vl = __riscv_vsetvl_e32m2(nbSequences-i);
// Loading structure member variables
vuint32m2x4_t v_tuple = __riscv_vlseg4e32_v_u32m2x4(
(const int32_t*)&inSeqs[i],
vl
);
vuint32m2_t v_offset = __riscv_vget_v_u32m2x4_u32m2(v_tuple, 0);
vuint32m2_t v_lit = __riscv_vget_v_u32m2x4_u32m2(v_tuple, 1);
vuint32m2_t v_match = __riscv_vget_v_u32m2x4_u32m2(v_tuple, 2);
// offset + ZSTD_REP_NUM
vuint32m2_t v_offBase = __riscv_vadd_vx_u32m2(v_offset, ZSTD_REP_NUM, vl);
// Check for integer overflow
// Cast to a 16-bit variable
vbool16_t lit_overflow = __riscv_vmsgtu_vx_u32m2_b16(v_lit, 65535, vl);
vuint16m1_t v_lit_clamped = __riscv_vncvt_x_x_w_u16m1(v_lit, vl);
vbool16_t ml_overflow = __riscv_vmsgtu_vx_u32m2_b16(v_match, 65535+MINMATCH, vl);
vuint16m1_t v_ml_clamped = __riscv_vncvt_x_x_w_u16m1(__riscv_vsub_vx_u32m2(v_match, MINMATCH, vl), vl);
// Pack two 16-bit fields into a 32-bit value (little-endian)
// The lower 16 bits contain litLength, and the upper 16 bits contain mlBase
vuint32m2_t v_lit_ml_combined = __riscv_vsll_vx_u32m2(
__riscv_vwcvtu_x_x_v_u32m2(v_ml_clamped, vl), // Convert matchLength to 32-bit
16,
vl
);
v_lit_ml_combined = __riscv_vor_vv_u32m2(
v_lit_ml_combined,
__riscv_vwcvtu_x_x_v_u32m2(v_lit_clamped, vl),
vl
);
// Create a vector of SeqDef structures
// Store the offBase, litLength, and mlBase in a vector of SeqDef
vuint32m2x2_t store_data = __riscv_vcreate_v_u32m2x2(
v_offBase,
v_lit_ml_combined
);
__riscv_vsseg2e32_v_u32m2x2(
(uint32_t*)&dstSeqs[i],
store_data,
vl
);
// Find the first index where an overflow occurs
int first_ml = __riscv_vfirst_m_b16(ml_overflow, vl);
int first_lit = __riscv_vfirst_m_b16(lit_overflow, vl);
if (UNLIKELY(first_ml != -1)) {
assert(longLen == 0);
longLen = i + first_ml + 1;
}
if (UNLIKELY(first_lit != -1)) {
assert(longLen == 0);
longLen = i + first_lit + 1 + nbSequences;
}
}
return longLen;
}
/* the vector implementation could also be ported to SSSE3,
* but since this implementation is targeting modern systems (>= Sapphire Rapid),
* it's not useful to develop and maintain code for older pre-AVX2 platforms */
@@ -7451,6 +7538,70 @@ BlockSummary ZSTD_get1BlockSummary(const ZSTD_Sequence* seqs, size_t nbSeqs)
}
}
#elif defined ZSTD_ARCH_RISCV_RVV
BlockSummary ZSTD_get1BlockSummary(const ZSTD_Sequence* seqs, size_t nbSeqs)
{
size_t totalMatchSize = 0;
size_t litSize = 0;
size_t i = 0;
int found_terminator = 0;
size_t vl_max = __riscv_vsetvlmax_e32m1();
vuint32m1_t v_lit_sum = __riscv_vmv_v_x_u32m1(0, vl_max);
vuint32m1_t v_match_sum = __riscv_vmv_v_x_u32m1(0, vl_max);
for (; i < nbSeqs; ) {
size_t vl = __riscv_vsetvl_e32m2(nbSeqs - i);
ptrdiff_t stride = sizeof(ZSTD_Sequence); // 16
vuint32m2x4_t v_tuple = __riscv_vlseg4e32_v_u32m2x4(
(const int32_t*)&seqs[i],
vl
);
vuint32m2_t v_offset = __riscv_vget_v_u32m2x4_u32m2(v_tuple, 0);
vuint32m2_t v_lit = __riscv_vget_v_u32m2x4_u32m2(v_tuple, 1);
vuint32m2_t v_match = __riscv_vget_v_u32m2x4_u32m2(v_tuple, 2);
// Check if any element has a matchLength of 0
vbool16_t mask = __riscv_vmseq_vx_u32m2_b16(v_match, 0, vl);
int first_zero = __riscv_vfirst_m_b16(mask, vl);
if (first_zero >= 0) {
// Find the first zero byte and set the effective length to that index + 1 to
// recompute the cumulative vector length of literals and matches
vl = first_zero + 1;
// recompute the cumulative vector length of literals and matches
v_lit_sum = __riscv_vredsum_vs_u32m2_u32m1(__riscv_vslidedown_vx_u32m2(v_lit, 0, vl), v_lit_sum, vl);
v_match_sum = __riscv_vredsum_vs_u32m2_u32m1(__riscv_vslidedown_vx_u32m2(v_match, 0, vl), v_match_sum, vl);
i += vl;
found_terminator = 1;
assert(seqs[i - 1].offset == 0);
break;
} else {
v_lit_sum = __riscv_vredsum_vs_u32m2_u32m1(v_lit, v_lit_sum, vl);
v_match_sum = __riscv_vredsum_vs_u32m2_u32m1(v_match, v_match_sum, vl);
i += vl;
}
}
litSize = __riscv_vmv_x_s_u32m1_u32(v_lit_sum);
totalMatchSize = __riscv_vmv_x_s_u32m1_u32(v_match_sum);
if (!found_terminator && i==nbSeqs) {
BlockSummary bs;
bs.nbSequences = ERROR(externalSequences_invalid);
return bs;
}
{ BlockSummary bs;
bs.nbSequences = i;
bs.blockSize = litSize + totalMatchSize;
bs.litSize = litSize;
return bs;
}
}
#else
BlockSummary ZSTD_get1BlockSummary(const ZSTD_Sequence* seqs, size_t nbSeqs)