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Changed default level 18 (large input) 

Previous -18 : 4.7 MB/s, R:3.833
New -18 : 5.1 MB/s. R:3.825

It's a better fit within -17 (6.8 MB/s) and -19 (4.0 MB/s)
The new level 18 also uses significantly less memory.
And, it makes a good transition between level 17 (mml5)
and level 19 (mml3).
Up to now, there was no level with mml4.

(note : minmatch setting can have a large impact on some (specific) datasets)
dev
Yann Collet 2017-04-27 17:44:01 -07:00
parent b636133932
commit 29297c6751
1 changed files with 1 additions and 1 deletions
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2
lib/compress/zstd_compress.c
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@ -3432,7 +3432,7 @@ static const ZSTD_compressionParameters ZSTD_defaultCParameters[4][ZSTD_MAX_CLEV
{ 22, 21, 21, 5, 5, 16, ZSTD_btlazy2 }, /* level 15 */
{ 23, 22, 22, 5, 5, 16, ZSTD_btlazy2 }, /* level 16 */
{ 23, 21, 22, 4, 5, 24, ZSTD_btopt }, /* level 17 */
{ 23, 23, 22, 6, 5, 32, ZSTD_btopt }, /* level 18 */
{ 23, 22, 22, 5, 4, 32, ZSTD_btopt }, /* level 18 */
{ 23, 23, 22, 6, 3, 48, ZSTD_btopt }, /* level 19 */
{ 25, 25, 23, 7, 3, 64, ZSTD_btopt2 }, /* level 20 */
{ 26, 26, 23, 7, 3,256, ZSTD_btopt2 }, /* level 21 */