@matheusbsbs / matheus-bagliano / commits / 8b2f8cbcb1

oidset: use khash

Reimplement oidset using khash.h in order to reduce its memory footprint and make it faster. Performance of a command that mainly checks for duplicate objects using an oidset, with master and Clang 6.0.1: $ cmd="./git-cat-file --batch-all-objects --unordered --buffer --batch-check='%(objectname)'" $ /usr/bin/time $cmd >/dev/null 0.22user 0.03system 0:00.25elapsed 99%CPU (0avgtext+0avgdata 48484maxresident)k 0inputs+0outputs (0major+11204minor)pagefaults 0swaps $ hyperfine "$cmd" Benchmark #1: ./git-cat-file --batch-all-objects --unordered --buffer --batch-check='%(objectname)' Time (mean ± σ): 250.0 ms ± 6.0 ms [User: 225.9 ms, System: 23.6 ms] Range (min … max): 242.0 ms … 261.1 ms And with this patch: $ /usr/bin/time $cmd >/dev/null 0.14user 0.00system 0:00.15elapsed 100%CPU (0avgtext+0avgdata 41396maxresident)k 0inputs+0outputs (0major+8318minor)pagefaults 0swaps $ hyperfine "$cmd" Benchmark #1: ./git-cat-file --batch-all-objects --unordered --buffer --batch-check='%(objectname)' Time (mean ± σ): 151.9 ms ± 4.9 ms [User: 130.5 ms, System: 21.2 ms] Range (min … max): 148.2 ms … 170.4 ms Initial-patch-by: Jeff King <peff@peff.net> Signed-off-by: Rene Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>

René Scharfe committed Oct 4, 2018 at 17:13 UTC 8b2f8cbcb16b1a9775214fe1d69aeb1580ae179d
2 files changed +40 -30
oidset.c
+12 -22
@@ -3,38 +3,28 @@
3
4 int oidset_contains(const struct oidset *set, const struct object_id *oid)
5 {
6 - if (!set->map.map.tablesize)
7 - return 0;
8 - return !!oidmap_get(&set->map, oid);
6 + khiter_t pos = kh_get_oid(&set->set, *oid);
7 + return pos != kh_end(&set->set);
8 }
9
10 int oidset_insert(struct oidset *set, const struct object_id *oid)
11 {
13 - struct oidmap_entry *entry;
14 -
15 - if (!set->map.map.tablesize)
16 - oidmap_init(&set->map, 0);
17 - else if (oidset_contains(set, oid))
18 - return 1;
19 -
20 - entry = xmalloc(sizeof(*entry));
21 - oidcpy(&entry->oid, oid);
22 -
23 - oidmap_put(&set->map, entry);
24 - return 0;
12 + int added;
13 + kh_put_oid(&set->set, *oid, &added);
14 + return !added;
15 }
16
17 int oidset_remove(struct oidset *set, const struct object_id *oid)
18 {
29 - struct oidmap_entry *entry;
30 -
31 - entry = oidmap_remove(&set->map, oid);
32 - free(entry);
33 -
34 - return (entry != NULL);
19 + khiter_t pos = kh_get_oid(&set->set, *oid);
20 + if (pos == kh_end(&set->set))
21 + return 0;
22 + kh_del_oid(&set->set, pos);
23 + return 1;
24 }
25
26 void oidset_clear(struct oidset *set)
27 {
39 - oidmap_free(&set->map, 1);
28 + kh_release_oid(&set->set);
29 + oidset_init(set, 0);
30 }
oidset.h
+28 -8
@@ -1,7 +1,8 @@
1 #ifndef OIDSET_H
2 #define OIDSET_H
3
4 -#include "oidmap.h"
4 +#include "hashmap.h"
5 +#include "khash.h"
6
7 /**
8 * This API is similar to sha1-array, in that it maintains a set of object ids
@@ -15,19 +16,33 @@
16 * table overhead.
17 */
18
19 +static inline unsigned int oid_hash(struct object_id oid)
20 +{
21 + return sha1hash(oid.hash);
22 +}
23 +
24 +static inline int oid_equal(struct object_id a, struct object_id b)
25 +{
26 + return oideq(&a, &b);
27 +}
28 +
29 +KHASH_INIT(oid, struct object_id, int, 0, oid_hash, oid_equal)
30 +
31 /**
32 * A single oidset; should be zero-initialized (or use OIDSET_INIT).
33 */
34 struct oidset {
22 - struct oidmap map;
35 + kh_oid_t set;
36 };
37
25 -#define OIDSET_INIT { OIDMAP_INIT }
38 +#define OIDSET_INIT { { 0 } }
39
40
41 static inline void oidset_init(struct oidset *set, size_t initial_size)
42 {
30 - oidmap_init(&set->map, initial_size);
43 + memset(&set->set, 0, sizeof(set->set));
44 + if (initial_size)
45 + kh_resize_oid(&set->set, initial_size);
46 }
47
48 /**
@@ -58,19 +73,24 @@ int oidset_remove(struct oidset *set, const struct object_id *oid);
73 void oidset_clear(struct oidset *set);
74
75 struct oidset_iter {
61 - struct oidmap_iter m_iter;
76 + kh_oid_t *set;
77 + khiter_t iter;
78 };
79
80 static inline void oidset_iter_init(struct oidset *set,
81 struct oidset_iter *iter)
82 {
67 - oidmap_iter_init(&set->map, &iter->m_iter);
83 + iter->set = &set->set;
84 + iter->iter = kh_begin(iter->set);
85 }
86
87 static inline struct object_id *oidset_iter_next(struct oidset_iter *iter)
88 {
72 - struct oidmap_entry *e = oidmap_iter_next(&iter->m_iter);
73 - return e ? &e->oid : NULL;
89 + for (; iter->iter != kh_end(iter->set); iter->iter++) {
90 + if (kh_exist(iter->set, iter->iter))
91 + return &kh_key(iter->set, iter->iter++);
92 + }
93 + return NULL;
94 }
95
96 static inline struct object_id *oidset_iter_first(struct oidset *set,