From 6c5d8d9e183a04007ecdfebff03079ea61ddd1eb Mon Sep 17 00:00:00 2001
From: Moinak Ghosh <moinakg@gmail.com>
Date: Wed, 24 Apr 2013 19:49:43 +0530
Subject: [PATCH] Optimize index lookup for 8-byte keys. More cleanups.

---
 rabin/global/index.c | 14 ++++++++++++--
 rabin/rabin_dedup.c  |  6 ++----
 2 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/rabin/global/index.c b/rabin/global/index.c
index 6a032ff..c6ba12c 100644
--- a/rabin/global/index.c
+++ b/rabin/global/index.c
@@ -168,7 +168,7 @@ set_cfg:
 	} else {
 		cfg->intervals = 100 / *pct_interval;
 		cfg->sub_intervals = cfg->intervals;
-		*hash_slots = file_sz / cfg->segment_sz_bytes + 1;
+		*hash_slots = file_sz / cfg->segment_sz_bytes;
 		*hash_slots *= cfg->sub_intervals;
 	}
 
@@ -320,7 +320,7 @@ int
 db_segcache_map(archive_config_t *cfg, int tid, uint32_t *blknum, uint64_t *offset, uchar_t **blocks)
 {
 	uchar_t *mapbuf, *hdr;
-	int fd;
+	int fd, dummy;
 	uint32_t len, adj;
 	uint64_t pos;
 
@@ -364,6 +364,7 @@ db_segcache_map(archive_config_t *cfg, int tid, uint32_t *blknum, uint64_t *offs
 	*blknum = *((uint32_t *)(hdr));
 	*offset = *((uint64_t *)(hdr + 4));
 	*blocks = hdr + SEGCACHE_HDR_SZ;
+	dummy = *(hdr + SEGCACHE_HDR_SZ);
 
 	cfg->seg_fd_r[tid].mapping = mapbuf;
 	cfg->seg_fd_r[tid].len = len + adj;
@@ -436,6 +437,15 @@ db_lookup_insert_s(archive_config_t *cfg, uchar_t *sim_cksum, int interval,
 			pent = &(ent->next);
 			ent = ent->next;
 		}
+	} else if (cfg->similarity_cksum_sz == 8) {
+		while (ent) {
+			if (*((uint64_t *)sim_cksum) == *((uint64_t *)ent->cksum) &&
+			    ent->item_offset != item_offset) {
+				return (ent);
+			}
+			pent = &(ent->next);
+			ent = ent->next;
+		}
 	} else {
 		while (ent) {
 			if (mycmp(sim_cksum, ent->cksum, cfg->similarity_cksum_sz) == 0 &&
diff --git a/rabin/rabin_dedup.c b/rabin/rabin_dedup.c
index 1cb6e7a..e1c8ebb 100755
--- a/rabin/rabin_dedup.c
+++ b/rabin/rabin_dedup.c
@@ -866,16 +866,14 @@ process_blocks:
 					 */
 					sim_ck = ctx->similarity_cksums;
 					sub_i = cfg->sub_intervals;
-					len = length;
 					tgt = seg_heap;
 					increment = cfg->chunk_cksum_sz;
-					if  (increment * sub_i > len)
-						sub_i = len / increment;
+					if  (increment * sub_i > length)
+						sub_i = length / increment;
 					for (j = 0; j<sub_i; j++) {
 						crc = lzma_crc64(tgt, increment/4, 0);
 						*((uint64_t *)sim_ck) = crc;
 						tgt += increment;
-						len -= increment;
 						sim_ck += cfg->similarity_cksum_sz;
 					}