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Prefetch First Batch of Match Positions; +11% Speed in Level 5 w/ 1 Dict

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This commit is contained in:
W. Felix Handte
2020-09-10 18:51:52 -04:00
parent df386b3d8d
commit 5e91ae27eb
1 changed files with 6 additions and 3 deletions
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lib/compress/zstd_lazy.c
+6 -3
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@@ -574,8 +574,7 @@ size_t ZSTD_HcFindBestMatch_generic (
const U32 ddsIndexDelta = dictLimit - ddsSize; const U32 ddsIndexDelta = dictLimit - ddsSize;
const U32 ddsMinChain = ddsSize > ddsChainSize ? ddsSize - ddsChainSize : 0; const U32 ddsMinChain = ddsSize > ddsChainSize ? ddsSize - ddsChainSize : 0;
const U32 bucketSize = (1 << DD_BLOG); const U32 bucketSize = (1 << DD_BLOG);
U32 attemptNb;
U32 attemptNb = 1;
matchIndex = dms->hashTable[ddsIdx]; matchIndex = dms->hashTable[ddsIdx];
@@ -583,7 +582,11 @@ size_t ZSTD_HcFindBestMatch_generic (
if (!matchIndex) if (!matchIndex)
return ml; return ml;
for ( ; (matchIndex>ddsLowestIndex) & (nbAttempts>0) ; nbAttempts--, attemptNb++) { for (attemptNb = 0; attemptNb < bucketSize; attemptNb++) {
PREFETCH_L1(ddsBase + dms->hashTable[ddsIdx + attemptNb]);
}
for (attemptNb = 1; (matchIndex>ddsLowestIndex) & (nbAttempts>0) ; nbAttempts--, attemptNb++) {
size_t currentMl=0; size_t currentMl=0;
const BYTE* const match = ddsBase + matchIndex; const BYTE* const match = ddsBase + matchIndex;
assert(match+4 <= ddsEnd); assert(match+4 <= ddsEnd);