Nguyễn Thái Ngọc DuyEvery time the object hash table grows, all entries must be rearranged. The few last times could be really expensive when the table contains a lot of entries.
When we do "--all --objects" we know in advance we may need to hash all objects. Just prepare the hash table big enough, so there won't be any resizing later on. The hash table is resized a couple times before prehash_objects() is called. But that's ok because there aren't many objects by that time (unless you have tons of refs, likely tags..)
On linux-2.6.git:
before after real 0m34.402s 0m33.288s user 0m34.111s 0m32.863s sys 0m0.205s 0m0.352s
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> --- object.c | 21 +++++++++++++++++++-- object.h | 2 ++ revision.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++++++---- 3 files changed, 76 insertions(+), 6 deletions(-)
Show changes to 3 files +76 −6
object.c, object.h, revision.c
diff --git a/object.c b/object.c index 20703f5..bcfd2c6 100644 --- a/object.c +++ b/object.c @@ -88,10 +88,10 @@ struct object *lookup_object(const unsigned char *sha1) return obj; } -static void grow_object_hash(void) +void grow_object_hash_to(unsigned long nr) { int i; - int new_hash_size = obj_hash_size < 32 ? 32 : 2 * obj_hash_size; + int new_hash_size = nr < 32 ? 32 : nr * 2; struct object **new_hash; new_hash = xcalloc(new_hash_size, sizeof(struct object *)); @@ -106,6 +106,11 @@ static void grow_object_hash(void) obj_hash_size = new_hash_size; } +static void grow_object_hash(void) +{ + grow_object_hash_to(obj_hash_size); +} + void *create_object(const unsigned char *sha1, int type, void *o) { struct object *obj = o; @@ -307,3 +312,15 @@ void clear_object_flags(unsigned flags) obj->flags &= ~flags; } } + +int has_object_flags(unsigned flags) +{ + int i; + + for (i = 0; i < obj_hash_size; i++) { + struct object *obj = obj_hash[i]; + if (obj && (obj->flags & flags)) + return 1; + } + return 0; +} diff --git a/object.h b/object.h index 97d384b..1e8fee8 100644 --- a/object.h +++ b/object.h @@ -52,6 +52,7 @@ extern struct object *get_indexed_object(unsigned int); */ struct object *lookup_object(const unsigned char *sha1); +extern void grow_object_hash_to(unsigned long nr); extern void *create_object(const unsigned char *sha1, int type, void *obj); /* @@ -87,6 +88,7 @@ void add_object_array(struct object *obj, const char *name, struct object_array void add_object_array_with_mode(struct object *obj, const char *name, struct object_array *array, unsigned mode); void object_array_remove_duplicates(struct object_array *); +int has_object_flags(unsigned flags); void clear_object_flags(unsigned flags); #endif /* OBJECT_H */ diff --git a/revision.c b/revision.c index 71e62d8..f9ea2d1 100644 --- a/revision.c +++ b/revision.c @@ -1665,8 +1665,9 @@ static int for_each_good_bisect_ref(const char *submodule, each_ref_fn fn, void } static int handle_revision_pseudo_opt(const char *submodule, - struct rev_info *revs, - int argc, const char **argv, int *flags) + struct rev_info *revs, + int argc, const char **argv, + int *flags, int *all) { const char *arg = argv[0]; const char *optarg; @@ -1685,6 +1686,7 @@ static int handle_revision_pseudo_opt(const char *submodule, if (!strcmp(arg, "--all")) { handle_refs(submodule, revs, *flags, for_each_ref_submodule); handle_refs(submodule, revs, *flags, head_ref_submodule); + *all = 1; } else if (!strcmp(arg, "--branches")) { handle_refs(submodule, revs, *flags, for_each_branch_ref_submodule); } else if (!strcmp(arg, "--bisect")) { @@ -1738,6 +1740,49 @@ static int handle_revision_pseudo_opt(const char *submodule, return 1; } +static void preallocate_hash_table(void) +{ + unsigned long cnt = 0; + struct packed_git *p; + int i; + + if (has_object_flags(UNINTERESTING)) + /* + * nope this is not simply "--all --objects" + * not worth preallocation. + */ + return; + + for (i = 0; i < 256; i++) { + struct dirent *ent; + DIR *d = opendir(git_path("objects/%02x", i)); + if (!d) + continue; + while ((ent = readdir(d)) != NULL) + /* + * We only worry about insufficient size which + * leads to expensive growths later on. A few + * extra slots in the hash table would not hurt. + */ + cnt++; + closedir(d); + } + + if (!packed_git) + prepare_packed_git(); + + for (p = packed_git; p; p = p->next) { + if (!p->pack_local) + /* this may lead to extra growths later */ + continue; + if (open_pack_index(p)) + continue; + cnt += p->num_objects; + } + + grow_object_hash_to(cnt); +} + /* * Parse revision information, filling in the "rev_info" structure, * and removing the used arguments from the argument list. @@ -1750,6 +1795,7 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct s int i, flags, left, seen_dashdash, read_from_stdin, got_rev_arg = 0, revarg_opt; struct cmdline_pathspec prune_data; const char *submodule = NULL; + int all = 0; memset(&prune_data, 0, sizeof(prune_data)); if (opt) @@ -1785,8 +1831,9 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct s int opts; opts = handle_revision_pseudo_opt(submodule, - revs, argc - i, argv + i, - &flags); + revs, argc - i, + argv + i, + &flags, &all); if (opts > 0) { i += opts - 1; continue; @@ -1856,6 +1903,10 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct s get_pathspec(revs->prefix, prune_data.path)); } + if (all && revs->tag_objects && + revs->tree_objects && revs->blob_objects) + preallocate_hash_table(); + if (revs->def == NULL) revs->def = opt ? opt->def : NULL; if (opt && opt->tweak)
-- 1.8.2.83.gc99314b
