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prefer memset() rather than reduceIndex() when close to index range limit

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by disabling continue mode when index is close to limit.
This commit is contained in:
Yann Collet 2019-06-21 16:19:21 -07:00
parent 944e2e9e12
commit 45c9fbd6d9
1 changed files with 19 additions and 4 deletions
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23
lib/compress/zstd_compress.c
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@ -692,13 +692,13 @@ size_t ZSTD_CCtxParams_getParameter(
*value = CCtxParams->compressionLevel; *value = CCtxParams->compressionLevel;
break; break;
case ZSTD_c_windowLog : case ZSTD_c_windowLog :
*value = CCtxParams->cParams.windowLog; *value = (int)CCtxParams->cParams.windowLog;
break; break;
case ZSTD_c_hashLog : case ZSTD_c_hashLog :
*value = CCtxParams->cParams.hashLog; *value = (int)CCtxParams->cParams.hashLog;
break; break;
case ZSTD_c_chainLog : case ZSTD_c_chainLog :
*value = CCtxParams->cParams.chainLog; *value = (int)CCtxParams->cParams.chainLog;
break; break;
case ZSTD_c_searchLog : case ZSTD_c_searchLog :
*value = CCtxParams->cParams.searchLog; *value = CCtxParams->cParams.searchLog;
@ -1376,6 +1376,19 @@ ZSTD_reset_matchState(ZSTD_matchState_t* ms,
return ptr; return ptr;
} }
/* ZSTD_index_valid_for_continue() :
* minor optimization : prefer triggering a memset() rather than reduceIndex()
* which can apparenly be measurably slow in some circumstances (reported for Visual Studio).
* Works when re-using a context for a lot of smallish inputs :
* if all inputs are smaller than ZSTD_INDEXOVERFLOW_MARGIN,
* memset() will be triggered before reduceIndex().
*/
#define ZSTD_INDEXOVERFLOW_MARGIN (16 MB)
static int ZSTD_index_valid_for_continue(ZSTD_window_t w)
{
return (size_t)(w.nextSrc - w.base) < (ZSTD_CURRENT_MAX - ZSTD_INDEXOVERFLOW_MARGIN);
}
#define ZSTD_WORKSPACETOOLARGE_FACTOR 3 /* define "workspace is too large" as this number of times larger than needed */ #define ZSTD_WORKSPACETOOLARGE_FACTOR 3 /* define "workspace is too large" as this number of times larger than needed */
#define ZSTD_WORKSPACETOOLARGE_MAXDURATION 128 /* when workspace is continuously too large #define ZSTD_WORKSPACETOOLARGE_MAXDURATION 128 /* when workspace is continuously too large
* during at least this number of times, * during at least this number of times,
@ -1399,7 +1412,9 @@ static size_t ZSTD_resetCCtx_internal(ZSTD_CCtx* zc,
if (ZSTD_equivalentParams(zc->appliedParams, params, if (ZSTD_equivalentParams(zc->appliedParams, params,
zc->inBuffSize, zc->inBuffSize,
zc->seqStore.maxNbSeq, zc->seqStore.maxNbLit, zc->seqStore.maxNbSeq, zc->seqStore.maxNbLit,
zbuff, pledgedSrcSize)) { zbuff, pledgedSrcSize)
&& ZSTD_index_valid_for_continue(zc->blockState.matchState.window)
) {
DEBUGLOG(4, "ZSTD_equivalentParams()==1 -> continue mode (wLog1=%u, blockSize1=%zu)", DEBUGLOG(4, "ZSTD_equivalentParams()==1 -> continue mode (wLog1=%u, blockSize1=%zu)",
zc->appliedParams.cParams.windowLog, zc->blockSize); zc->appliedParams.cParams.windowLog, zc->blockSize);
zc->workSpaceOversizedDuration += (zc->workSpaceOversizedDuration > 0); /* if it was too large, it still is */ zc->workSpaceOversizedDuration += (zc->workSpaceOversizedDuration > 0); /* if it was too large, it still is */