greg/pcompress
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

Reduce dedupe hash table collisions by half.

Browse source
This commit is contained in:
Moinak Ghosh 2013-01-31 00:38:41 +05:30
parent 3d8f3ada1c
commit af4c6e1d84
1 changed files with 3 additions and 3 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

6
rabin/rabin_dedup.c
View file

@ -560,7 +560,7 @@ process_blocks:
DEBUG_STAT_EN(delta_fails = 0); DEBUG_STAT_EN(delta_fails = 0);
DEBUG_STAT_EN(hash_collisions = 0); DEBUG_STAT_EN(hash_collisions = 0);
ary_sz = blknum * sizeof (rabin_blockentry_t *); ary_sz = (blknum << 1) * sizeof (rabin_blockentry_t *);
htab = (rabin_blockentry_t **)(ctx->cbuf + ctx->real_chunksize - ary_sz); htab = (rabin_blockentry_t **)(ctx->cbuf + ctx->real_chunksize - ary_sz);
memset(htab, 0, ary_sz); memset(htab, 0, ary_sz);
@ -598,8 +598,8 @@ process_blocks:
* not enabled then value of similarity_hash == hash. * not enabled then value of similarity_hash == hash.
*/ */
ck = ctx->blocks[i]->similarity_hash; ck = ctx->blocks[i]->similarity_hash;
ck += (ck / ctx->blocks[i]->length); ck ^= (ck / ctx->blocks[i]->length);
j = ck % blknum; j = ck % (blknum << 1);
if (htab[j] == 0) { if (htab[j] == 0) {
/* /*