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Commit 0ba9ea9

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author
Junio C Hamano
committed
Merge branch 'jc/thinpack' into next
* jc/thinpack: Thin pack generation: optimization.
2 parents fcedc5a + 5379a5c commit 0ba9ea9

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+236
-48
lines changed

1 file changed

+236
-48
lines changed

‎pack-objects.c‎

Lines changed: 236 additions & 48 deletions
Original file line numberDiff line numberDiff line change
@@ -453,7 +453,7 @@ static void rehash_objects(void)
453453
if (object_ix_hashsz < 1024)
454454
object_ix_hashsz = 1024;
455455
object_ix = xrealloc(object_ix, sizeof(int) * object_ix_hashsz);
456-
object_ix = memset(object_ix, 0, sizeof(int) * object_ix_hashsz);
456+
memset(object_ix, 0, sizeof(int) * object_ix_hashsz);
457457
for (i = 0, oe = objects; i < nr_objects; i++, oe++) {
458458
int ix = locate_object_entry_hash(oe->sha1);
459459
if (0 <= ix)
@@ -505,21 +505,6 @@ static unsigned name_hash(struct name_path *path, const char *name)
505505
* but close enough.
506506
*/
507507
hash = (name_hash<<DIRBITS) | (hash & ((1U<<DIRBITS )-1));
508-
509-
if (0) { /* debug */
510-
n = name + strlen(name);
511-
if (n != name && n[-1] == '\n')
512-
n--;
513-
while (name <= --n)
514-
fputc(*n, stderr);
515-
for (p = path; p; p = p->up) {
516-
fputc('/', stderr);
517-
n = p->elem + p->len;
518-
while (p->elem <= --n)
519-
fputc(*n, stderr);
520-
}
521-
fprintf(stderr, "\t%08x\n", hash);
522-
}
523508
return hash;
524509
}
525510

@@ -587,56 +572,254 @@ static int add_object_entry(const unsigned char *sha1, unsigned hash, int exclud
587572
return status;
588573
}
589574

590-
static void add_pbase_tree(struct tree_desc *tree, struct name_path *up)
575+
struct pbase_tree_cache {
576+
unsigned char sha1[20];
577+
int ref;
578+
int temporary;
579+
void *tree_data;
580+
unsigned long tree_size;
581+
};
582+
583+
static struct pbase_tree_cache *(pbase_tree_cache[256]);
584+
static int pbase_tree_cache_ix(const unsigned char *sha1)
585+
{
586+
return sha1[0] % ARRAY_SIZE(pbase_tree_cache);
587+
}
588+
static int pbase_tree_cache_ix_incr(int ix)
589+
{
590+
return (ix+1) % ARRAY_SIZE(pbase_tree_cache);
591+
}
592+
593+
static struct pbase_tree {
594+
struct pbase_tree *next;
595+
/* This is a phony "cache" entry; we are not
596+
* going to evict it nor find it through _get()
597+
* mechanism -- this is for the toplevel node that
598+
* would almost always change with any commit.
599+
*/
600+
struct pbase_tree_cache pcache;
601+
} *pbase_tree;
602+
603+
static struct pbase_tree_cache *pbase_tree_get(const unsigned char *sha1)
604+
{
605+
struct pbase_tree_cache *ent, *nent;
606+
void *data;
607+
unsigned long size;
608+
char type[20];
609+
int neigh;
610+
int my_ix = pbase_tree_cache_ix(sha1);
611+
int available_ix = -1;
612+
613+
/* pbase-tree-cache acts as a limited hashtable.
614+
* your object will be found at your index or within a few
615+
* slots after that slot if it is cached.
616+
*/
617+
for (neigh = 0; neigh < 8; neigh++) {
618+
ent = pbase_tree_cache[my_ix];
619+
if (ent && !memcmp(ent->sha1, sha1, 20)) {
620+
ent->ref++;
621+
return ent;
622+
}
623+
else if (((available_ix < 0) && (!ent || !ent->ref)) ||
624+
((0 <= available_ix) &&
625+
(!ent && pbase_tree_cache[available_ix])))
626+
available_ix = my_ix;
627+
if (!ent)
628+
break;
629+
my_ix = pbase_tree_cache_ix_incr(my_ix);
630+
}
631+
632+
/* Did not find one. Either we got a bogus request or
633+
* we need to read and perhaps cache.
634+
*/
635+
data = read_sha1_file(sha1, type, &size);
636+
if (!data)
637+
return NULL;
638+
if (strcmp(type, tree_type)) {
639+
free(data);
640+
return NULL;
641+
}
642+
643+
/* We need to either cache or return a throwaway copy */
644+
645+
if (available_ix < 0)
646+
ent = NULL;
647+
else {
648+
ent = pbase_tree_cache[available_ix];
649+
my_ix = available_ix;
650+
}
651+
652+
if (!ent) {
653+
nent = xmalloc(sizeof(*nent));
654+
nent->temporary = (available_ix < 0);
655+
}
656+
else {
657+
/* evict and reuse */
658+
free(ent->tree_data);
659+
nent = ent;
660+
}
661+
memcpy(nent->sha1, sha1, 20);
662+
nent->tree_data = data;
663+
nent->tree_size = size;
664+
nent->ref = 1;
665+
if (!nent->temporary)
666+
pbase_tree_cache[my_ix] = nent;
667+
return nent;
668+
}
669+
670+
static void pbase_tree_put(struct pbase_tree_cache *cache)
671+
{
672+
if (!cache->temporary) {
673+
cache->ref--;
674+
return;
675+
}
676+
free(cache->tree_data);
677+
free(cache);
678+
}
679+
680+
static int name_cmp_len(const char *name)
681+
{
682+
int i;
683+
for (i = 0; name[i] && name[i] != '\n' && name[i] != '/'; i++)
684+
;
685+
return i;
686+
}
687+
688+
static void add_pbase_object(struct tree_desc *tree,
689+
struct name_path *up,
690+
const char *name,
691+
int cmplen)
591692
{
592693
while (tree->size) {
593694
const unsigned char *sha1;
594-
const char *name;
595-
unsigned mode, hash;
695+
const char *entry_name;
696+
int entry_len;
697+
unsigned mode;
596698
unsigned long size;
597699
char type[20];
598700

599-
sha1 = tree_entry_extract(tree, &name, &mode);
701+
sha1 = tree_entry_extract(tree, &entry_name, &mode);
600702
update_tree_entry(tree);
601-
if (!has_sha1_file(sha1))
602-
continue;
603-
if (sha1_object_info(sha1, type, &size))
703+
entry_len = strlen(entry_name);
704+
if (entry_len != cmplen ||
705+
memcmp(entry_name, name, cmplen) ||
706+
!has_sha1_file(sha1) ||
707+
sha1_object_info(sha1, type, &size))
604708
continue;
605-
606-
hash = name_hash(up, name);
607-
if (!add_object_entry(sha1, hash, 1))
608-
continue;
609-
709+
if (name[cmplen] != '/') {
710+
unsigned hash = name_hash(up, name);
711+
add_object_entry(sha1, hash, 1);
712+
return;
713+
}
610714
if (!strcmp(type, tree_type)) {
611715
struct tree_desc sub;
612-
void *elem;
613716
struct name_path me;
717+
struct pbase_tree_cache *tree;
718+
const char *down = name+cmplen+1;
719+
int downlen = name_cmp_len(down);
720+
721+
tree = pbase_tree_get(sha1);
722+
if (!tree)
723+
return;
724+
sub.buf = tree->tree_data;
725+
sub.size = tree->tree_size;
726+
727+
me.up = up;
728+
me.elem = entry_name;
729+
me.len = entry_len;
730+
add_pbase_object(&sub, &me, down, downlen);
731+
pbase_tree_put(tree);
732+
}
733+
}
734+
}
614735

615-
elem = read_sha1_file(sha1, type, &sub.size);
616-
sub.buf = elem;
617-
if (sub.buf) {
618-
me.up = up;
619-
me.elem = name;
620-
me.len = strlen(name);
621-
add_pbase_tree(&sub, &me);
622-
free(elem);
623-
}
736+
static unsigned *done_pbase_paths;
737+
static int done_pbase_paths_num;
738+
static int done_pbase_paths_alloc;
739+
static int done_pbase_path_pos(unsigned hash)
740+
{
741+
int lo = 0;
742+
int hi = done_pbase_paths_num;
743+
while (lo < hi) {
744+
int mi = (hi + lo) / 2;
745+
if (done_pbase_paths[mi] == hash)
746+
return mi;
747+
if (done_pbase_paths[mi] < hash)
748+
hi = mi;
749+
else
750+
lo = mi + 1;
751+
}
752+
return -lo-1;
753+
}
754+
755+
static int check_pbase_path(unsigned hash)
756+
{
757+
int pos = (!done_pbase_paths) ? -1 : done_pbase_path_pos(hash);
758+
if (0 <= pos)
759+
return 1;
760+
pos = -pos - 1;
761+
if (done_pbase_paths_alloc <= done_pbase_paths_num) {
762+
done_pbase_paths_alloc = alloc_nr(done_pbase_paths_alloc);
763+
done_pbase_paths = xrealloc(done_pbase_paths,
764+
done_pbase_paths_alloc *
765+
sizeof(unsigned));
766+
}
767+
done_pbase_paths_num++;
768+
if (pos < done_pbase_paths_num)
769+
memmove(done_pbase_paths + pos + 1,
770+
done_pbase_paths + pos,
771+
(done_pbase_paths_num - pos - 1) * sizeof(unsigned));
772+
done_pbase_paths[pos] = hash;
773+
return 0;
774+
}
775+
776+
static void add_preferred_base_object(char *name, unsigned hash)
777+
{
778+
struct pbase_tree *it;
779+
int cmplen = name_cmp_len(name);
780+
781+
if (check_pbase_path(hash))
782+
return;
783+
784+
for (it = pbase_tree; it; it = it->next) {
785+
if (cmplen == 0) {
786+
hash = name_hash(NULL, "");
787+
add_object_entry(it->pcache.sha1, hash, 1);
788+
}
789+
else {
790+
struct tree_desc tree;
791+
tree.buf = it->pcache.tree_data;
792+
tree.size = it->pcache.tree_size;
793+
add_pbase_object(&tree, NULL, name, cmplen);
624794
}
625795
}
626796
}
627797

628798
static void add_preferred_base(unsigned char *sha1)
629799
{
630-
struct tree_desc tree;
631-
void *elem;
800+
struct pbase_tree *it;
801+
void *data;
802+
unsigned long size;
803+
unsigned char tree_sha1[20];
632804

633-
elem = read_object_with_reference(sha1, tree_type, &tree.size, NULL);
634-
tree.buf = elem;
635-
if (!tree.buf)
805+
data = read_object_with_reference(sha1, tree_type, &size, tree_sha1);
806+
if (!data)
636807
return;
637-
if (add_object_entry(sha1, name_hash(NULL, ""), 1))
638-
add_pbase_tree(&tree, NULL);
639-
free(elem);
808+
809+
for (it = pbase_tree; it; it = it->next) {
810+
if (!memcmp(it->pcache.sha1, tree_sha1, 20)) {
811+
free(data);
812+
return;
813+
}
814+
}
815+
816+
it = xcalloc(1, sizeof(*it));
817+
it->next = pbase_tree;
818+
pbase_tree = it;
819+
820+
memcpy(it->pcache.sha1, tree_sha1, 20);
821+
it->pcache.tree_data = data;
822+
it->pcache.tree_size = size;
640823
}
641824

642825
static void check_object(struct object_entry *entry)
@@ -1051,6 +1234,7 @@ int main(int argc, char **argv)
10511234
char line[PATH_MAX + 20];
10521235
int window = 10, depth = 10, pack_to_stdout = 0;
10531236
struct object_entry **list;
1237+
int num_preferred_base = 0;
10541238
int i;
10551239

10561240
setup_git_directory();
@@ -1116,6 +1300,7 @@ int main(int argc, char **argv)
11161300

11171301
for (;;) {
11181302
unsigned char sha1[20];
1303+
unsigned hash;
11191304

11201305
if (!fgets(line, sizeof(line), stdin)) {
11211306
if (feof(stdin))
@@ -1132,12 +1317,15 @@ int main(int argc, char **argv)
11321317
if (get_sha1_hex(line+1, sha1))
11331318
die("expected edge sha1, got garbage:\n %s",
11341319
line+1);
1135-
add_preferred_base(sha1);
1320+
if (num_preferred_base++ < window)
1321+
add_preferred_base(sha1);
11361322
continue;
11371323
}
11381324
if (get_sha1_hex(line, sha1))
11391325
die("expected sha1, got garbage:\n %s", line);
1140-
add_object_entry(sha1, name_hash(NULL, line+41), 0);
1326+
hash = name_hash(NULL, line+41);
1327+
add_preferred_base_object(line+41, hash);
1328+
add_object_entry(sha1, hash, 0);
11411329
}
11421330
if (progress)
11431331
fprintf(stderr, "Done counting %d objects.\n", nr_objects);

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