facebook/zstd
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Skip most long matches in lazy hash table update

Browse Source
This commit is contained in:
Sen Huang 2021-08-18 06:52:17 -07:00
parent 9ef055d706
commit b8fd6bf30c
2 changed files with 804 additions and 793 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
lib/compress/zstd_lazy.c
View File

@ -971,7 +971,7 @@ FORCE_INLINE_TEMPLATE void ZSTD_row_prefetch(U32 const* hashTable, U16 const* ta
* Fill up the hash cache starting at idx, prefetching up to ZSTD_ROW_HASH_CACHE_SIZE entries, * Fill up the hash cache starting at idx, prefetching up to ZSTD_ROW_HASH_CACHE_SIZE entries,
* but not beyond iLimit. * but not beyond iLimit.
*/ */
static void ZSTD_row_fillHashCache(ZSTD_matchState_t* ms, const BYTE* base, FORCE_INLINE_TEMPLATE void ZSTD_row_fillHashCache(ZSTD_matchState_t* ms, const BYTE* base,
U32 const rowLog, U32 const mls, U32 const rowLog, U32 const mls,
U32 idx, const BYTE* const iLimit) U32 idx, const BYTE* const iLimit)
{ {
@ -1022,9 +1022,20 @@ FORCE_INLINE_TEMPLATE void ZSTD_row_update_internal(ZSTD_matchState_t* ms, const
U32* const hashTable = ms->hashTable; U32* const hashTable = ms->hashTable;
U16* const tagTable = ms->tagTable; U16* const tagTable = ms->tagTable;
U32 const hashLog = ms->rowHashLog; U32 const hashLog = ms->rowHashLog;
U32 idx = ms->nextToUpdate;
const BYTE* const base = ms->window.base; const BYTE* const base = ms->window.base;
const U32 target = (U32)(ip - base); const U32 target = (U32)(ip - base);
U32 idx = ms->nextToUpdate; const U32 kMaxPositionsToUpdate = 256;
assert(target >= idx);
if (useCache) {
/* Only skip positions when using hash cache, i.e.
if we are loading a dict, don't skip anything */
if (UNLIKELY(target - idx > kMaxPositionsToUpdate)) {
idx = target - kMaxPositionsToUpdate;
ZSTD_row_fillHashCache(ms, base, rowLog, mls, idx, ip+1);
}
}
DEBUGLOG(6, "ZSTD_row_update_internal(): nextToUpdate=%u, current=%u", idx, target); DEBUGLOG(6, "ZSTD_row_update_internal(): nextToUpdate=%u, current=%u", idx, target);
for (; idx < target; ++idx) { for (; idx < target; ++idx) {
@ -1037,7 +1048,7 @@ FORCE_INLINE_TEMPLATE void ZSTD_row_update_internal(ZSTD_matchState_t* ms, const
U32 const pos = ZSTD_row_nextIndex(tagRow, rowMask); U32 const pos = ZSTD_row_nextIndex(tagRow, rowMask);
assert(hash == ZSTD_hashPtr(base + idx, hashLog + ZSTD_ROW_HASH_TAG_BITS, mls)); assert(hash == ZSTD_hashPtr(base + idx, hashLog + ZSTD_ROW_HASH_TAG_BITS, mls));
((BYTE*)tagRow)[pos + ZSTD_ROW_HASH_TAG_OFFSET] = hash & ZSTD_ROW_HASH_TAG_MASK; tagRow[pos + ZSTD_ROW_HASH_TAG_OFFSET] = hash & ZSTD_ROW_HASH_TAG_MASK;
row[pos] = idx; row[pos] = idx;
} }
ms->nextToUpdate = target; ms->nextToUpdate = target;

1580
tests/regression/results.csv
View File

File diff suppressed because it is too large Load Diff