From 751a71e2b5f3667ab7ffffccad3e2b58726eb1c9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lukas=20Sandstr=C3=B6m?= <lukass@etek.chalmers.se>
Date: Thu, 17 Nov 2005 14:11:56 +0100
Subject: [PATCH] Make git-pack-redundant non-horribly slow on large sets of
packs
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Change the smallest-set detection algortithm so that when
we have found a good set, we don't check any larger sets.
Signed-off-by: Lukas Sandström <lukass@etek.chalmers.se>
Signed-off-by: Junio C Hamano <junkio@cox.net>
---
pack-redundant.c | 58 +++++++++++++++++++++++++++++++++++++++---------
1 file changed, 47 insertions(+), 11 deletions(-)
diff --git a/pack-redundant.c b/pack-redundant.c
index fcb36ff9016..51d7341b0b9 100644
--- a/pack-redundant.c
+++ b/pack-redundant.c
@@ -33,6 +33,7 @@ struct pack_list {
struct pll {
struct pll *next;
struct pack_list *pl;
+ size_t pl_size;
};
inline void llist_free(struct llist *list)
@@ -249,18 +250,45 @@ void cmp_two_packs(struct pack_list *p1, struct pack_list *p2)
}
}
+void pll_insert(struct pll **pll, struct pll **hint_table)
+{
+ struct pll *prev;
+ int i = (*pll)->pl_size - 1;
+
+ if (hint_table[i] == NULL) {
+ hint_table[i--] = *pll;
+ for (; i >= 0; --i) {
+ if (hint_table[i] != NULL)
+ break;
+ }
+ if (hint_table[i] == NULL) /* no elements in list */
+ die("Why did this happen?");
+ }
+
+ prev = hint_table[i];
+ while (prev->next && prev->next->pl_size < (*pll)->pl_size)
+ prev = prev->next;
+
+ (*pll)->next = prev->next;
+ prev->next = *pll;
+}
+
/* all the permutations have to be free()d at the same time,
* since they refer to each other
*/
struct pll * get_all_permutations(struct pack_list *list)
{
struct pll *subset, *pll, *new_pll = NULL; /*silence warning*/
-
+ static struct pll **hint = NULL;
+ if (hint == NULL)
+ hint = xcalloc(pack_list_size(list), sizeof(struct pll *));
+
if (list == NULL)
return NULL;
if (list->next == NULL) {
new_pll = xmalloc(sizeof(struct pll));
+ hint[0] = new_pll;
new_pll->next = NULL;
new_pll->pl = list;
return new_pll;
@@ -268,24 +296,30 @@ struct pll * get_all_permutations(struct pack_list *list)
pll = subset = get_all_permutations(list->next);
while (pll) {
+ if (pll->pl->pack == list->pack) {
+ pll = pll->next;
+ continue;
+ }
new_pll = xmalloc(sizeof(struct pll));
- new_pll->next = pll->next;
- pll->next = new_pll;
new_pll->pl = xmalloc(sizeof(struct pack_list));
memcpy(new_pll->pl, list, sizeof(struct pack_list));
new_pll->pl->next = pll->pl;
+ new_pll->pl_size = pll->pl_size + 1;
+
+ pll_insert(&new_pll, hint);
- pll = new_pll->next;
+ pll = pll->next;
}
- /* add ourself to the end */
- new_pll->next = xmalloc(sizeof(struct pll));
- new_pll->next->pl = xmalloc(sizeof(struct pack_list));
- new_pll->next->next = NULL;
- memcpy(new_pll->next->pl, list, sizeof(struct pack_list));
- new_pll->next->pl->next = NULL;
+ /* add ourself */
+ new_pll = xmalloc(sizeof(struct pll));
+ new_pll->pl = xmalloc(sizeof(struct pack_list));
+ memcpy(new_pll->pl, list, sizeof(struct pack_list));
+ new_pll->pl->next = NULL;
+ new_pll->pl_size = 1;
+ pll_insert(&new_pll, hint);
- return subset;
+ return hint[0];
}
int is_superset(struct pack_list *pl, struct llist *list)
@@ -401,6 +435,8 @@ void minimize(struct pack_list **min)
/* find the permutations which contain all missing objects */
perm_all = perm = get_all_permutations(non_unique);
while (perm) {
+ if (perm_ok && perm->pl_size > perm_ok->pl_size)
+ break; /* ignore all larger permutations */
if (is_superset(perm->pl, missing)) {
new_perm = xmalloc(sizeof(struct pll));
new_perm->pl = perm->pl;