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This removes the old `ZSTD_compressBlock_fast_generic()` and renames the new
`ZSTD_compressBlock_fast_generic_pipelined()` to replace it. This is
functionally a no-op.
This commit is contained in:
W. Felix Handte 2021-08-26 13:29:58 -04:00
parent 64054dec44
commit 15e67bfa7e
1 changed files with 21 additions and 156 deletions
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177
lib/compress/zstd_fast.c
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@ -43,146 +43,6 @@ void ZSTD_fillHashTable(ZSTD_matchState_t* ms,
} }
FORCE_INLINE_TEMPLATE size_t
ZSTD_compressBlock_fast_generic(
ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
void const* src, size_t srcSize,
U32 const mls)
{
const ZSTD_compressionParameters* const cParams = &ms->cParams;
U32* const hashTable = ms->hashTable;
U32 const hlog = cParams->hashLog;
/* support stepSize of 0 */
size_t const stepSize = cParams->targetLength + !(cParams->targetLength) + 1;
const BYTE* const base = ms->window.base;
const BYTE* const istart = (const BYTE*)src;
/* We check ip0 (ip + 0) and ip1 (ip + 1) each loop */
const BYTE* ip0 = istart;
const BYTE* ip1;
const BYTE* anchor = istart;
const U32 endIndex = (U32)((size_t)(istart - base) + srcSize);
const U32 prefixStartIndex = ZSTD_getLowestPrefixIndex(ms, endIndex, cParams->windowLog);
const BYTE* const prefixStart = base + prefixStartIndex;
const BYTE* const iend = istart + srcSize;
const BYTE* const ilimit = iend - HASH_READ_SIZE;
U32 offset_1=rep[0], offset_2=rep[1];
U32 offsetSaved = 0;
/* init */
DEBUGLOG(5, "ZSTD_compressBlock_fast_generic");
ip0 += (ip0 == prefixStart);
ip1 = ip0 + 1;
{ U32 const curr = (U32)(ip0 - base);
U32 const windowLow = ZSTD_getLowestPrefixIndex(ms, curr, cParams->windowLog);
U32 const maxRep = curr - windowLow;
if (offset_2 > maxRep) offsetSaved = offset_2, offset_2 = 0;
if (offset_1 > maxRep) offsetSaved = offset_1, offset_1 = 0;
}
/* Main Search Loop */
#ifdef __INTEL_COMPILER
/* From intel 'The vector pragma indicates that the loop should be
* vectorized if it is legal to do so'. Can be used together with
* #pragma ivdep (but have opted to exclude that because intel
* warns against using it).*/
#pragma vector always
#endif
while (ip1 < ilimit) { /* < instead of <=, because check at ip0+2 */
size_t mLength;
BYTE const* ip2 = ip0 + 2;
size_t const h0 = ZSTD_hashPtr(ip0, hlog, mls);
U32 const val0 = MEM_read32(ip0);
size_t const h1 = ZSTD_hashPtr(ip1, hlog, mls);
U32 const val1 = MEM_read32(ip1);
U32 const current0 = (U32)(ip0-base);
U32 const current1 = (U32)(ip1-base);
U32 const matchIndex0 = hashTable[h0];
U32 const matchIndex1 = hashTable[h1];
BYTE const* repMatch = ip2 - offset_1;
const BYTE* match0 = base + matchIndex0;
const BYTE* match1 = base + matchIndex1;
U32 offcode;
#if defined(__aarch64__)
PREFETCH_L1(ip0+256);
#endif
hashTable[h0] = current0; /* update hash table */
hashTable[h1] = current1; /* update hash table */
assert(ip0 + 1 == ip1);
if ((offset_1 > 0) & (MEM_read32(repMatch) == MEM_read32(ip2))) {
mLength = (ip2[-1] == repMatch[-1]) ? 1 : 0;
ip0 = ip2 - mLength;
match0 = repMatch - mLength;
mLength += 4;
offcode = 0;
goto _match;
}
if ((matchIndex0 > prefixStartIndex) && MEM_read32(match0) == val0) {
/* found a regular match */
goto _offset;
}
if ((matchIndex1 > prefixStartIndex) && MEM_read32(match1) == val1) {
/* found a regular match after one literal */
ip0 = ip1;
match0 = match1;
goto _offset;
}
{ size_t const step = ((size_t)(ip0-anchor) >> (kSearchStrength - 1)) + stepSize;
assert(step >= 2);
ip0 += step;
ip1 += step;
continue;
}
_offset: /* Requires: ip0, match0 */
/* Compute the offset code */
offset_2 = offset_1;
offset_1 = (U32)(ip0-match0);
offcode = offset_1 + ZSTD_REP_MOVE;
mLength = 4;
/* Count the backwards match length */
while (((ip0>anchor) & (match0>prefixStart))
&& (ip0[-1] == match0[-1])) { ip0--; match0--; mLength++; } /* catch up */
_match: /* Requires: ip0, match0, offcode */
/* Count the forward length */
mLength += ZSTD_count(ip0+mLength, match0+mLength, iend);
ZSTD_storeSeq(seqStore, (size_t)(ip0-anchor), anchor, iend, offcode, mLength-MINMATCH);
/* match found */
ip0 += mLength;
anchor = ip0;
if (ip0 <= ilimit) {
/* Fill Table */
assert(base+current0+2 > istart); /* check base overflow */
hashTable[ZSTD_hashPtr(base+current0+2, hlog, mls)] = current0+2; /* here because current+2 could be > iend-8 */
hashTable[ZSTD_hashPtr(ip0-2, hlog, mls)] = (U32)(ip0-2-base);
if (offset_2 > 0) { /* offset_2==0 means offset_2 is invalidated */
while ( (ip0 <= ilimit) && (MEM_read32(ip0) == MEM_read32(ip0 - offset_2)) ) {
/* store sequence */
size_t const rLength = ZSTD_count(ip0+4, ip0+4-offset_2, iend) + 4;
{ U32 const tmpOff = offset_2; offset_2 = offset_1; offset_1 = tmpOff; } /* swap offset_2 <=> offset_1 */
hashTable[ZSTD_hashPtr(ip0, hlog, mls)] = (U32)(ip0-base);
ip0 += rLength;
ZSTD_storeSeq(seqStore, 0 /*litLen*/, anchor, iend, 0 /*offCode*/, rLength-MINMATCH);
anchor = ip0;
continue; /* faster when present (confirmed on gcc-8) ... (?) */
} } }
ip1 = ip0 + 1;
}
/* save reps for next block */
rep[0] = offset_1 ? offset_1 : offsetSaved;
rep[1] = offset_2 ? offset_2 : offsetSaved;
/* Return the last literals size */
return (size_t)(iend - anchor);
}
/** /**
* If you squint hard enough (and ignore repcodes), the search operation at any * If you squint hard enough (and ignore repcodes), the search operation at any
* given position is broken into 4 stages: * given position is broken into 4 stages:
@ -200,14 +60,20 @@ _match: /* Requires: ip0, match0, offcode */
* onto the next, this implementation interleaves these operations across the * onto the next, this implementation interleaves these operations across the
* next few positions: * next few positions:
* *
* R = Repcode Read & Compare
* H = Hash
* T = Table Lookup
* M = Match Read & Compare
*
* Pos | Time --> * Pos | Time -->
* ----+------------------- * ----+-------------------
* N | ...4 * N | ... M
* N+1 | ... 3 4 * N+1 | ... TM
* N+2 | ... 2 3 4 * N+2 | R H T M
* N+3 | 1 2 3 * N+3 | H TM
* N+4 | 1 2 * N+4 | R H T M
* N+5 | 1 * N+5 | H ...
* N+6 | R ...
* *
* This is very much analogous to the pipelining of execution in a CPU. And just * This is very much analogous to the pipelining of execution in a CPU. And just
* like a CPU, we have to dump the pipeline when we find a match (i.e., take a * like a CPU, we have to dump the pipeline when we find a match (i.e., take a
@ -218,14 +84,13 @@ _match: /* Requires: ip0, match0, offcode */
* *
* Pos | Time --> * Pos | Time -->
* ----+------------------- * ----+-------------------
* N | 1 2 3 * N | H T
* N+1 | 1 2 * N+1 | H
* N+2 | 1
* *
* This is also the work we do at the beginning to enter the loop initially. * This is also the work we do at the beginning to enter the loop initially.
*/ */
FORCE_INLINE_TEMPLATE size_t FORCE_INLINE_TEMPLATE size_t
ZSTD_compressBlock_fast_generic_pipelined( ZSTD_compressBlock_fast_generic(
ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
void const* src, size_t srcSize, void const* src, size_t srcSize,
U32 const mls) U32 const mls)
@ -267,7 +132,7 @@ ZSTD_compressBlock_fast_generic_pipelined(
const BYTE* nextStep; const BYTE* nextStep;
const size_t kStepIncr = (1 << (kSearchStrength - 1)); const size_t kStepIncr = (1 << (kSearchStrength - 1));
DEBUGLOG(5, "ZSTD_compressBlock_fast_generic_pipelined"); DEBUGLOG(5, "ZSTD_compressBlock_fast_generic");
ip0 += (ip0 == prefixStart); ip0 += (ip0 == prefixStart);
{ U32 const curr = (U32)(ip0 - base); { U32 const curr = (U32)(ip0 - base);
U32 const windowLow = ZSTD_getLowestPrefixIndex(ms, curr, cParams->windowLog); U32 const windowLow = ZSTD_getLowestPrefixIndex(ms, curr, cParams->windowLog);
@ -456,13 +321,13 @@ size_t ZSTD_compressBlock_fast(
{ {
default: /* includes case 3 */ default: /* includes case 3 */
case 4 : case 4 :
return ZSTD_compressBlock_fast_generic_pipelined(ms, seqStore, rep, src, srcSize, 4); return ZSTD_compressBlock_fast_generic(ms, seqStore, rep, src, srcSize, 4);
case 5 : case 5 :
return ZSTD_compressBlock_fast_generic_pipelined(ms, seqStore, rep, src, srcSize, 5); return ZSTD_compressBlock_fast_generic(ms, seqStore, rep, src, srcSize, 5);
case 6 : case 6 :
return ZSTD_compressBlock_fast_generic_pipelined(ms, seqStore, rep, src, srcSize, 6); return ZSTD_compressBlock_fast_generic(ms, seqStore, rep, src, srcSize, 6);
case 7 : case 7 :
return ZSTD_compressBlock_fast_generic_pipelined(ms, seqStore, rep, src, srcSize, 7); return ZSTD_compressBlock_fast_generic(ms, seqStore, rep, src, srcSize, 7);
} }
} }
@ -665,7 +530,7 @@ static size_t ZSTD_compressBlock_fast_extDict_generic(
/* switch to "regular" variant if extDict is invalidated due to maxDistance */ /* switch to "regular" variant if extDict is invalidated due to maxDistance */
if (prefixStartIndex == dictStartIndex) if (prefixStartIndex == dictStartIndex)
return ZSTD_compressBlock_fast_generic_pipelined(ms, seqStore, rep, src, srcSize, mls); return ZSTD_compressBlock_fast_generic(ms, seqStore, rep, src, srcSize, mls);
/* Search Loop */ /* Search Loop */
while (ip < ilimit) { /* < instead of <=, because (ip+1) */ while (ip < ilimit) { /* < instead of <=, because (ip+1) */