Reduce RowHash's tag space size by x2 (#3543)

Allocate half the memory for tag space, which means that we get one less slot for an actual tag (needs to be used for next position index). The results is a slight loss in compression ratio (up to 0.2%) and some regressions/improvements to speed depending on level and sample. In turn, we get to save 16% of the hash table's space (5 bytes per entry instead of 6 bytes per entry).
2023-03-10 14:15:04 -08:00
parent 134d332b10
commit 33e39094e7
5 changed files with 320 additions and 321 deletions
@@ -2422,7 +2422,7 @@ static int basicUnitTests(U32 const seed, double compressibility)
                                                 3663, 3662, 3661, 3660, 3660,
                                                 3660, 3660, 3660 };
            size_t const target_wdict_cSize[22+1] =  { 2830, 2896, 2893, 2820, 2940,
-                                                       2950, 2950, 2925, 2900, 2891,
+                                                       2950, 2950, 2925, 2900, 2892,
                                                       2910, 2910, 2910, 2780, 2775,
                                                       2765, 2760, 2755, 2754, 2753,
                                                       2753, 2753, 2753 };