From: Eric Wong <e@80x24.org>
To: git@vger.kernel.org
Cc: "Jeff King" <peff@peff.net>, "René Scharfe" <l.s.r@web.de>
Subject: [PATCH 1/5] speed up alt_odb_usable() with many alternates
Date: Sun, 27 Jun 2021 02:47:14 +0000 [thread overview]
Message-ID: <20210627024718.25383-2-e@80x24.org> (raw)
In-Reply-To: <20210627024718.25383-1-e@80x24.org>
With many alternates, the duplicate check in alt_odb_usable()
wastes many cycles doing repeated fspathcmp() on every existing
alternate. Use a khash to speed up lookups by odb->path.
Since the kh_put_* API uses the supplied key without
duplicating it, we also take advantage of it to replace both
xstrdup() and strbuf_release() in link_alt_odb_entry() with
strbuf_detach() to avoid the allocation and copy.
In a test repository with 50K alternates and each of those 50K
alternates having one alternate each (for a total of 100K total
alternates); this speeds up lookup of a non-existent blob from
over 16 minutes to roughly 2.7 seconds on my busy workstation.
Note: all underlying git object directories were small and
unpacked with only loose objects and no packs. Having to load
packs increases times significantly.
Signed-off-by: Eric Wong <e@80x24.org>
---
object-file.c | 33 ++++++++++++++++++++++-----------
object-store.h | 17 +++++++++++++++++
object.c | 2 ++
3 files changed, 41 insertions(+), 11 deletions(-)
diff --git a/object-file.c b/object-file.c
index f233b440b2..304af3a172 100644
--- a/object-file.c
+++ b/object-file.c
@@ -517,9 +517,9 @@ const char *loose_object_path(struct repository *r, struct strbuf *buf,
*/
static int alt_odb_usable(struct raw_object_store *o,
struct strbuf *path,
- const char *normalized_objdir)
+ const char *normalized_objdir, khiter_t *pos)
{
- struct object_directory *odb;
+ int r;
/* Detect cases where alternate disappeared */
if (!is_directory(path->buf)) {
@@ -533,14 +533,22 @@ static int alt_odb_usable(struct raw_object_store *o,
* Prevent the common mistake of listing the same
* thing twice, or object directory itself.
*/
- for (odb = o->odb; odb; odb = odb->next) {
- if (!fspathcmp(path->buf, odb->path))
- return 0;
+ if (!o->odb_by_path) {
+ khiter_t p;
+
+ o->odb_by_path = kh_init_odb_path_map();
+ assert(!o->odb->next);
+ p = kh_put_odb_path_map(o->odb_by_path, o->odb->path, &r);
+ if (r < 0) die_errno(_("kh_put_odb_path_map"));
+ assert(r == 1); /* never used */
+ kh_value(o->odb_by_path, p) = o->odb;
}
if (!fspathcmp(path->buf, normalized_objdir))
return 0;
-
- return 1;
+ *pos = kh_put_odb_path_map(o->odb_by_path, path->buf, &r);
+ if (r < 0) die_errno(_("kh_put_odb_path_map"));
+ /* r: 0 = exists, 1 = never used, 2 = deleted */
+ return r == 0 ? 0 : 1;
}
/*
@@ -566,6 +574,7 @@ static int link_alt_odb_entry(struct repository *r, const char *entry,
{
struct object_directory *ent;
struct strbuf pathbuf = STRBUF_INIT;
+ khiter_t pos;
if (!is_absolute_path(entry) && relative_base) {
strbuf_realpath(&pathbuf, relative_base, 1);
@@ -587,23 +596,25 @@ static int link_alt_odb_entry(struct repository *r, const char *entry,
while (pathbuf.len && pathbuf.buf[pathbuf.len - 1] == '/')
strbuf_setlen(&pathbuf, pathbuf.len - 1);
- if (!alt_odb_usable(r->objects, &pathbuf, normalized_objdir)) {
+ if (!alt_odb_usable(r->objects, &pathbuf, normalized_objdir, &pos)) {
strbuf_release(&pathbuf);
return -1;
}
CALLOC_ARRAY(ent, 1);
- ent->path = xstrdup(pathbuf.buf);
+ /* pathbuf.buf is already in r->objects->odb_by_path */
+ ent->path = strbuf_detach(&pathbuf, NULL);
/* add the alternate entry */
*r->objects->odb_tail = ent;
r->objects->odb_tail = &(ent->next);
ent->next = NULL;
+ assert(r->objects->odb_by_path);
+ kh_value(r->objects->odb_by_path, pos) = ent;
/* recursively add alternates */
- read_info_alternates(r, pathbuf.buf, depth + 1);
+ read_info_alternates(r, ent->path, depth + 1);
- strbuf_release(&pathbuf);
return 0;
}
diff --git a/object-store.h b/object-store.h
index ec32c23dcb..20c1cedb75 100644
--- a/object-store.h
+++ b/object-store.h
@@ -7,6 +7,8 @@
#include "oid-array.h"
#include "strbuf.h"
#include "thread-utils.h"
+#include "khash.h"
+#include "dir.h"
struct object_directory {
struct object_directory *next;
@@ -30,6 +32,19 @@ struct object_directory {
char *path;
};
+static inline int odb_path_eq(const char *a, const char *b)
+{
+ return !fspathcmp(a, b);
+}
+
+static inline int odb_path_hash(const char *str)
+{
+ return ignore_case ? strihash(str) : __ac_X31_hash_string(str);
+}
+
+KHASH_INIT(odb_path_map, const char * /* key: odb_path */,
+ struct object_directory *, 1, odb_path_hash, odb_path_eq);
+
void prepare_alt_odb(struct repository *r);
char *compute_alternate_path(const char *path, struct strbuf *err);
typedef int alt_odb_fn(struct object_directory *, void *);
@@ -116,6 +131,8 @@ struct raw_object_store {
*/
struct object_directory *odb;
struct object_directory **odb_tail;
+ kh_odb_path_map_t *odb_by_path;
+
int loaded_alternates;
/*
diff --git a/object.c b/object.c
index 14188453c5..2b3c075a15 100644
--- a/object.c
+++ b/object.c
@@ -511,6 +511,8 @@ static void free_object_directories(struct raw_object_store *o)
free_object_directory(o->odb);
o->odb = next;
}
+ kh_destroy_odb_path_map(o->odb_by_path);
+ o->odb_by_path = NULL;
}
void raw_object_store_clear(struct raw_object_store *o)
next prev parent reply other threads:[~2021-06-27 2:47 UTC|newest]
Thread overview: 99+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-24 0:58 [PATCH] speed up alt_odb_usable() with many alternates Eric Wong
2021-06-27 2:47 ` [PATCH 0/5] optimizations for many odb alternates Eric Wong
2021-06-27 2:47 ` Eric Wong [this message]
2021-06-27 2:47 ` [PATCH 2/5] avoid strlen via strbuf_addstr in link_alt_odb_entry Eric Wong
2021-06-27 2:47 ` [PATCH 3/5] make object_directory.loose_objects_subdir_seen a bitmap Eric Wong
2021-06-27 10:23 ` René Scharfe
2021-06-28 23:09 ` Eric Wong
2021-06-27 2:47 ` [PATCH 4/5] oidcpy_with_padding: constify `src' arg Eric Wong
2021-06-27 2:47 ` [PATCH 5/5] oidtree: a crit-bit tree for odb_loose_cache Eric Wong
2021-06-29 14:42 ` Junio C Hamano
2021-06-29 20:17 ` Eric Wong
2021-06-29 20:53 ` [PATCH v2 0/5] optimizations for many alternates Eric Wong
2021-07-07 23:10 ` [PATCH v3 " Eric Wong
2021-07-07 23:10 ` [PATCH v3 1/5] speed up alt_odb_usable() with " Eric Wong
2021-07-08 0:20 ` Junio C Hamano
2021-07-08 1:14 ` Eric Wong
2021-07-08 4:30 ` Junio C Hamano
2021-07-07 23:10 ` [PATCH v3 2/5] avoid strlen via strbuf_addstr in link_alt_odb_entry Eric Wong
2021-07-08 4:57 ` Junio C Hamano
2021-07-07 23:10 ` [PATCH v3 3/5] make object_directory.loose_objects_subdir_seen a bitmap Eric Wong
2021-07-07 23:10 ` [PATCH v3 4/5] oidcpy_with_padding: constify `src' arg Eric Wong
2021-07-07 23:10 ` [PATCH v3 5/5] oidtree: a crit-bit tree for odb_loose_cache Eric Wong
2021-06-29 20:53 ` [PATCH v2 1/5] speed up alt_odb_usable() with many alternates Eric Wong
2021-07-03 10:05 ` René Scharfe
2021-07-04 9:02 ` René Scharfe
2021-07-06 23:01 ` Eric Wong
2021-06-29 20:53 ` [PATCH v2 2/5] avoid strlen via strbuf_addstr in link_alt_odb_entry Eric Wong
2021-06-29 20:53 ` [PATCH v2 3/5] make object_directory.loose_objects_subdir_seen a bitmap Eric Wong
2021-06-29 20:53 ` [PATCH v2 4/5] oidcpy_with_padding: constify `src' arg Eric Wong
2021-06-29 20:53 ` [PATCH v2 5/5] oidtree: a crit-bit tree for odb_loose_cache Eric Wong
2021-07-04 9:02 ` René Scharfe
2021-07-06 23:21 ` Eric Wong
2021-07-04 9:32 ` Ævar Arnfjörð Bjarmason
2021-07-07 23:12 ` Eric Wong
2021-08-06 15:31 ` Andrzej Hunt
2021-08-06 17:53 ` René Scharfe
2021-08-07 22:49 ` Eric Wong
2021-08-09 1:35 ` Carlo Arenas
2021-08-09 1:38 ` [PATCH/RFC 0/3] pedantic errors in next Carlo Marcelo Arenas Belón
2021-08-09 1:38 ` [PATCH/RFC 1/3] oidtree: avoid nested struct oidtree_node Carlo Marcelo Arenas Belón
2021-08-09 1:38 ` [PATCH/RFC 2/3] object-store: avoid extra ';' from KHASH_INIT Carlo Marcelo Arenas Belón
2021-08-09 15:53 ` Junio C Hamano
2021-08-09 1:38 ` [PATCH/RFC 3/3] ci: run a pedantic build as part of the GitHub workflow Carlo Marcelo Arenas Belón
2021-08-09 10:50 ` Bagas Sanjaya
2021-08-09 22:03 ` Carlo Arenas
2021-08-09 14:56 ` Phillip Wood
2021-08-09 22:48 ` Carlo Arenas
2021-08-10 15:24 ` Phillip Wood
2021-08-10 18:25 ` Junio C Hamano
2021-08-30 11:36 ` Ævar Arnfjörð Bjarmason
2021-08-31 20:28 ` Carlo Arenas
2021-08-31 20:51 ` Ævar Arnfjörð Bjarmason
2021-08-31 23:54 ` Carlo Arenas
2021-09-01 1:52 ` Jeff King
2021-09-01 17:55 ` Junio C Hamano
2021-08-30 11:40 ` Ævar Arnfjörð Bjarmason
2021-09-01 9:19 ` [RFC PATCH v2 0/4] developer: support pedantic Carlo Marcelo Arenas Belón
2021-09-01 9:19 ` [RFC PATCH v2 1/4] developer: retire USE_PARENS_AROUND_GETTEXT_N support Carlo Marcelo Arenas Belón
2021-09-01 9:19 ` [RFC PATCH v2 2/4] developer: enable pedantic by default Carlo Marcelo Arenas Belón
2021-09-01 9:19 ` [RFC PATCH v2 3/4] developer: add an alternative script for detecting broken N_() Carlo Marcelo Arenas Belón
2021-09-01 9:19 ` [RFC PATCH v2 4/4] developer: move detect-compiler out of the main directory Carlo Marcelo Arenas Belón
2021-09-01 10:10 ` [RFC PATCH v2 0/4] developer: support pedantic Jeff King
2021-09-01 11:25 ` [PATCH] gettext: remove optional non-standard parens in N_() definition Ævar Arnfjörð Bjarmason
2021-09-01 17:31 ` Eric Sunshine
2021-09-02 9:13 ` Jeff King
2021-09-02 19:19 ` Junio C Hamano
2021-09-01 11:27 ` [RFC PATCH v2 0/4] developer: support pedantic Ævar Arnfjörð Bjarmason
2021-09-01 18:03 ` Carlo Arenas
2021-09-03 17:02 ` [PATCH v3 0/3] support pedantic in developer mode Carlo Marcelo Arenas Belón
2021-09-03 17:02 ` [PATCH v3 1/3] gettext: remove optional non-standard parens in N_() definition Carlo Marcelo Arenas Belón
2021-09-10 15:39 ` Ævar Arnfjörð Bjarmason
2021-09-03 17:02 ` [PATCH v3 2/3] win32: allow building with pedantic mode enabled Carlo Marcelo Arenas Belón
2021-09-03 18:47 ` René Scharfe
2021-09-03 20:13 ` Carlo Marcelo Arenas Belón
2021-09-03 20:32 ` Junio C Hamano
2021-09-03 20:38 ` René Scharfe
2021-09-04 9:37 ` René Scharfe
2021-09-04 14:42 ` Carlo Arenas
2021-09-27 23:04 ` Jonathan Tan
2021-09-28 0:30 ` Carlo Arenas
2021-09-28 16:50 ` Jonathan Tan
2021-09-28 17:37 ` Junio C Hamano
2021-09-28 20:16 ` Jonathan Tan
2021-09-29 1:00 ` Carlo Arenas
2021-09-29 15:55 ` Junio C Hamano
2021-09-03 17:02 ` [PATCH v3 3/3] developer: enable pedantic by default Carlo Marcelo Arenas Belón
2021-09-05 7:54 ` [PATCH v3 0/3] support pedantic in developer mode Ævar Arnfjörð Bjarmason
2021-08-09 16:44 ` [PATCH/RFC 0/3] pedantic errors in next Junio C Hamano
2021-08-09 20:10 ` Eric Wong
2021-08-10 6:16 ` Carlo Marcelo Arenas Belón
2021-08-10 19:30 ` René Scharfe
2021-08-10 23:49 ` Carlo Arenas
2021-08-11 0:57 ` Carlo Arenas
2021-08-11 14:57 ` René Scharfe
2021-08-11 17:20 ` Junio C Hamano
2021-08-10 18:59 ` [PATCH v2 5/5] oidtree: a crit-bit tree for odb_loose_cache René Scharfe
2021-08-10 19:40 ` René Scharfe
2021-08-14 20:00 ` [PATCH] oidtree: avoid unaligned access to crit-bit tree René Scharfe
2021-08-16 19:11 ` Junio C Hamano
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