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diffcore-delta: make the hash a bit denser.

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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>
This commit is contained in:
Junio C Hamano 2006-03-12 16:39:51 -08:00
parent c06c79667c
commit 2821104db7
2 changed files with 11 additions and 6 deletions
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13
diffcore-delta.c
View File

@ -25,8 +25,12 @@
*/ */
/* Wild guess at the initial hash size */ /* Wild guess at the initial hash size */
#define INITIAL_HASH_SIZE 10 #define INITIAL_HASH_SIZE 9
#define HASHBASE 65537 /* next_prime(2^16) */ #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 { struct spanhash {
unsigned long hashval; unsigned long hashval;
@ -38,7 +42,8 @@ struct spanhash_top {
struct spanhash data[FLEX_ARRAY]; 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 sz = 1 << top->alloc_log2;
int bucket = hashval & (sz - 1); 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 = xmalloc(sizeof(*orig) + sizeof(struct spanhash) * sz);
new->alloc_log2 = orig->alloc_log2 + 1; 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); memset(new->data, 0, sizeof(struct spanhash) * sz);
for (i = 0; i < osz; i++) { for (i = 0; i < osz; i++) {
struct spanhash *o = &(orig->data[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; i = INITIAL_HASH_SIZE;
hash = xmalloc(sizeof(*hash) + sizeof(struct spanhash) * (1<<i)); hash = xmalloc(sizeof(*hash) + sizeof(struct spanhash) * (1<<i));
hash->alloc_log2 = i; hash->alloc_log2 = i;
hash->free = (1<<i)/2; hash->free = INITIAL_FREE(i);
memset(hash->data, 0, sizeof(struct spanhash) * (1<<i)); memset(hash->data, 0, sizeof(struct spanhash) * (1<<i));
/* an 8-byte shift register made of accum1 and accum2. New /* an 8-byte shift register made of accum1 and accum2. New

4
diffcore-rename.c
View File

@ -307,8 +307,8 @@ void diffcore_rename(struct diff_options *options)
m->score = estimate_similarity(one, two, m->score = estimate_similarity(one, two,
minimum_score); minimum_score);
} }
free(two->cnt_data); /* We do not need the text anymore */
two->cnt_data = NULL; diff_free_filespec_data(two);
dst_cnt++; dst_cnt++;
} }
/* cost matrix sorted by most to least similar pair */ /* cost matrix sorted by most to least similar pair */