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

performance tweak : bt search w/ long repeated segments

dev
Yann Collet 2016-02-15 14:07:07 +01:00
parent cefef8cde7
commit b37e0a9241
2 changed files with 16 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

30
lib/zstd_compress.c
View File

@ -1319,13 +1319,20 @@ static size_t ZSTD_insertBtAndFindBestMatch (
}
static void ZSTD_updateTree(ZSTD_CCtx* zc, const BYTE* const ip, const BYTE* const iend, const U32 nbCompares, const U32 mls)
#define BT_MAXREF_1 16
#define BT_MAXREF_2 128
#define BT_MAXREF (BT_MAXREF_1 + BT_MAXREF_2)
static void ZSTD_updateTree(ZSTD_CCtx* zc, const BYTE* const ip, const BYTE* const iend, const U32 nbCompares, const U32 mls, U32 extDict, U32 noSkip)
{
const BYTE* const base = zc->base;
const U32 target = (U32)(ip - base);
U32 idx = zc->nextToUpdate;
while(idx < target) idx += ZSTD_insertBt1(zc, base+idx, mls, iend, nbCompares, 0);
if ((!noSkip) && (idx + BT_MAXREF < target)) {
U32 t2 = idx + BT_MAXREF_1;
while(idx < t2) idx += ZSTD_insertBt1(zc, base+idx, mls, iend, nbCompares, extDict);
idx = target - BT_MAXREF_2;
}
while(idx < target) idx += ZSTD_insertBt1(zc, base+idx, mls, iend, nbCompares, extDict);
}
/** Tree updater, providing best match */
@ -1336,7 +1343,7 @@ static size_t ZSTD_BtFindBestMatch (
const U32 maxNbAttempts, const U32 mls)
{
if (ip < zc->base + zc->nextToUpdate) return 0; /* skipped area */
ZSTD_updateTree(zc, ip, iLimit, maxNbAttempts, mls);
ZSTD_updateTree(zc, ip, iLimit, maxNbAttempts, mls, 0, 0);
return ZSTD_insertBtAndFindBestMatch(zc, ip, iLimit, offsetPtr, maxNbAttempts, mls, 0);
}
@ -1357,15 +1364,6 @@ static size_t ZSTD_BtFindBestMatch_selectMLS (
}
static void ZSTD_updateTree_extDict(ZSTD_CCtx* zc, const BYTE* const ip, const BYTE* const iend, const U32 nbCompares, const U32 mls)
{
const BYTE* const base = zc->base;
const U32 target = (U32)(ip - base);
U32 idx = zc->nextToUpdate;
while (idx < target) idx += ZSTD_insertBt1(zc, base+idx, mls, iend, nbCompares, 1);
}
/** Tree updater, providing best match */
static size_t ZSTD_BtFindBestMatch_extDict (
@ -1375,7 +1373,7 @@ static size_t ZSTD_BtFindBestMatch_extDict (
const U32 maxNbAttempts, const U32 mls)
{
if (ip < zc->base + zc->nextToUpdate) return 0; /* skipped area */
ZSTD_updateTree_extDict(zc, ip, iLimit, maxNbAttempts, mls);
ZSTD_updateTree(zc, ip, iLimit, maxNbAttempts, mls, 1, 0);
return ZSTD_insertBtAndFindBestMatch(zc, ip, iLimit, offsetPtr, maxNbAttempts, mls, 1);
}
@ -2056,7 +2054,7 @@ static size_t ZSTD_loadDictionaryContent(ZSTD_CCtx* zc, const void* src, size_t
case ZSTD_btlazy2:
case ZSTD_btopt:
ZSTD_updateTree(zc, iend-8, iend, 1 << zc->params.searchLog, zc->params.searchLength);
ZSTD_updateTree(zc, iend-8, iend, 1 << zc->params.searchLog, zc->params.searchLength, 0, 1);
break;
default:
@ -2329,7 +2327,7 @@ static const ZSTD_parameters ZSTD_defaultParameters[4][ZSTD_MAX_CLEVEL+1] = {
{ 0, 17, 17, 16, 6, 4, 4, ZSTD_lazy2 }, /* level 10 */
{ 0, 17, 17, 17, 7, 4, 4, ZSTD_lazy2 }, /* level 11 */
{ 0, 17, 17, 17, 8, 4, 4, ZSTD_lazy2 }, /* level 12 */
{ 0, 17, 17, 17, 9, 4, 4, ZSTD_lazy2 }, /* level 13 */
{ 0, 17, 18, 17, 5, 4, 4, ZSTD_btlazy2 }, /* level 13 */
{ 0, 17, 18, 16, 5, 4, 20, ZSTD_btopt }, /* level 14 */
{ 0, 17, 18, 16, 9, 4, 48, ZSTD_btopt }, /* level 15 */
{ 0, 17, 18, 17, 7, 4,128, ZSTD_btopt }, /* level 16 */

4
lib/zstd_opt.h
View File

@ -264,7 +264,7 @@ U32 ZSTD_BtGetAllMatches (
const U32 maxNbAttempts, const U32 mls, ZSTD_match_t* matches, U32 minml)
{
if (ip < zc->base + zc->nextToUpdate) return 0; /* skipped area */
ZSTD_updateTree(zc, ip, iLimit, maxNbAttempts, mls);
ZSTD_updateTree(zc, ip, iLimit, maxNbAttempts, mls, 0, 0);
return ZSTD_insertBtAndGetAllMatches(zc, ip, iLimit, maxNbAttempts, mls, 0, matches, minml);
}
@ -292,7 +292,7 @@ U32 ZSTD_BtGetAllMatches_extDict (
const U32 maxNbAttempts, const U32 mls, ZSTD_match_t* matches, U32 minml)
{
if (ip < zc->base + zc->nextToUpdate) return 0; /* skipped area */
ZSTD_updateTree_extDict(zc, ip, iLimit, maxNbAttempts, mls);
ZSTD_updateTree(zc, ip, iLimit, maxNbAttempts, mls, 1, 0);
return ZSTD_insertBtAndGetAllMatches(zc, ip, iLimit, maxNbAttempts, mls, 1, matches, minml);
}