From 2821104db7fabdfac105ae757228b0eac107047c Mon Sep 17 00:00:00 2001
From: Junio C Hamano <junkio@cox.net>
Date: Sun, 12 Mar 2006 16:39:51 -0800
Subject: [PATCH] diffcore-delta: make the hash a bit denser.
To reduce wasted memory, wait until the hash fills up more
densely before we rehash. This reduces the working set size a
bit further.
Signed-off-by: Junio C Hamano <junkio@cox.net>
---
diffcore-delta.c | 13 +++++++++----
diffcore-rename.c | 4 ++--
2 files changed, 11 insertions(+), 6 deletions(-)
diff --git a/diffcore-delta.c b/diffcore-delta.c
index 471b98f05d..f8a751837e 100644
--- a/diffcore-delta.c
+++ b/diffcore-delta.c
@@ -25,8 +25,12 @@
*/
/* Wild guess at the initial hash size */
-#define INITIAL_HASH_SIZE 10
+#define INITIAL_HASH_SIZE 9
#define HASHBASE 65537 /* next_prime(2^16) */
+/* We leave more room in smaller hash but do not let it
+ * grow to have unused hole too much.
+ */
+#define INITIAL_FREE(sz_log2) ((1<<(sz_log2))*(sz_log2-3)/(sz_log2))
struct spanhash {
unsigned long hashval;
@@ -38,7 +42,8 @@ struct spanhash_top {
struct spanhash data[FLEX_ARRAY];
};
-static struct spanhash *spanhash_find(struct spanhash_top *top, unsigned long hashval)
+static struct spanhash *spanhash_find(struct spanhash_top *top,
+ unsigned long hashval)
{
int sz = 1 << top->alloc_log2;
int bucket = hashval & (sz - 1);
@@ -62,7 +67,7 @@ static struct spanhash_top *spanhash_rehash(struct spanhash_top *orig)
new = xmalloc(sizeof(*orig) + sizeof(struct spanhash) * sz);
new->alloc_log2 = orig->alloc_log2 + 1;
- new->free = osz;
+ new->free = INITIAL_FREE(new->alloc_log2);
memset(new->data, 0, sizeof(struct spanhash) * sz);
for (i = 0; i < osz; i++) {
struct spanhash *o = &(orig->data[i]);
@@ -122,7 +127,7 @@ static struct spanhash_top *hash_chars(unsigned char *buf, unsigned long sz)
i = INITIAL_HASH_SIZE;
hash = xmalloc(sizeof(*hash) + sizeof(struct spanhash) * (1<<i));
hash->alloc_log2 = i;
- hash->free = (1<<i)/2;
+ hash->free = INITIAL_FREE(i);
memset(hash->data, 0, sizeof(struct spanhash) * (1<<i));
/* an 8-byte shift register made of accum1 and accum2. New
diff --git a/diffcore-rename.c b/diffcore-rename.c
index b80b4320ff..ed99fe2cc0 100644
--- a/diffcore-rename.c
+++ b/diffcore-rename.c
@@ -307,8 +307,8 @@ void diffcore_rename(struct diff_options *options)
m->score = estimate_similarity(one, two,
minimum_score);
}
- free(two->cnt_data);
- two->cnt_data = NULL;
+ /* We do not need the text anymore */
+ diff_free_filespec_data(two);
dst_cnt++;
}
/* cost matrix sorted by most to least similar pair */