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Merge pull request #1449 from facebook/ovlog_def

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overlapLog default values
This commit is contained in:
Yann Collet
2018-12-18 09:45:53 -08:00
committed by GitHub
parent 345af8abc7 96adc846c5
commit 517d8c984c
16 changed files with 221 additions and 147 deletions
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programs/fileio.c
+1 -4
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@@ -561,12 +561,9 @@ static cRess_t FIO_createCResources(const char* dictFileName, int cLevel,
DISPLAYLEVEL(5,"set nb workers = %u \n", g_nbWorkers);
CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_nbWorkers, g_nbWorkers) );
CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_jobSize, g_blockSize) );
if ( (g_overlapLog == FIO_OVERLAP_LOG_NOTSET)
&& (cLevel == ZSTD_maxCLevel()) )
g_overlapLog = 9; /* full overlap */
if (g_overlapLog != FIO_OVERLAP_LOG_NOTSET) {
DISPLAYLEVEL(3,"set overlapLog = %u \n", g_overlapLog);
CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_overlapSizeLog, g_overlapLog) );
CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_overlapLog, g_overlapLog) );
}
CHECK( ZSTD_CCtx_setParameter(ress.cctx, ZSTD_c_rsyncable, g_rsyncable) );
#endif
programs/zstd.1
+1 -1
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@@ -389,7 +389,7 @@ The minimum \fItlen\fR is 0 and the maximum is 999\.
Determine \fBoverlapSize\fR, amount of data reloaded from previous job\. This parameter is only available when multithreading is enabled\. Reloading more data improves compression ratio, but decreases speed\.
.
.IP
The minimum \fIovlog\fR is 0, and the maximum is 9\. 0 means "no overlap", hence completely independent jobs\. 9 means "full overlap", meaning up to \fBwindowSize\fR is reloaded from previous job\. Reducing \fIovlog\fR by 1 reduces the amount of reload by a factor 2\. Default \fIovlog\fR is 6, which means "reload \fBwindowSize / 8\fR"\. Exception : the maximum compression level (22) has a default \fIovlog\fR of 9\.
The minimum \fIovlog\fR is 0, and the maximum is 9\. 1 means "no overlap", hence completely independent jobs\. 9 means "full overlap", meaning up to \fBwindowSize\fR is reloaded from previous job\. Reducing \fIovlog\fR by 1 reduces the reloaded amount by a factor 2\. For example, 8 means "windowSize/2", and 6 means "windowSize/8"\. Value 0 is special and means "default" : \fIovlog\fR is automatically determined by \fBzstd\fR\. In which case, \fIovlog\fR will range from 6 to 9, depending on selected \fIstrat\fR\.
.
.TP
\fBldmHashLog\fR=\fIlhlog\fR, \fBlhlog\fR=\fIlhlog\fR
programs/zstd.1.md
+5 -4
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@@ -417,11 +417,12 @@ The list of available _options_:
Reloading more data improves compression ratio, but decreases speed.
The minimum _ovlog_ is 0, and the maximum is 9.
0 means "no overlap", hence completely independent jobs.
1 means "no overlap", hence completely independent jobs.
9 means "full overlap", meaning up to `windowSize` is reloaded from previous job.
Reducing _ovlog_ by 1 reduces the amount of reload by a factor 2.
Default _ovlog_ is 6, which means "reload `windowSize / 8`".
Exception : the maximum compression level (22) has a default _ovlog_ of 9.
Reducing _ovlog_ by 1 reduces the reloaded amount by a factor 2.
For example, 8 means "windowSize/2", and 6 means "windowSize/8".
Value 0 is special and means "default" : _ovlog_ is automatically determined by `zstd`.
In which case, _ovlog_ will range from 6 to 9, depending on selected _strat_.
- `ldmHashLog`=_lhlog_, `lhlog`=_lhlog_:
Specify the maximum size for a hash table used for long distance matching.