@matheusbsbs / matheus-bagliano / commits / 0aaf05b3bd

sha1_name: use bsearch_pack() for abbreviations

When computing abbreviation lengths for an object ID against a single packfile, the method find_abbrev_len_for_pack() currently implements binary search. This is one of several implementations. One issue with this implementation is that it ignores the fanout table in the pack- index. Translate this binary search to use the existing bsearch_pack() method that correctly uses a fanout table. Due to the use of the fanout table, the abbreviation computation is slightly faster than before. For a fully-repacked copy of the Linux repo, the following 'git log' commands improved: * git log --oneline --parents --raw Before: 59.2s After: 56.9s Rel %: -3.8% * git log --oneline --parents Before: 6.48s After: 5.91s Rel %: -8.9% Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Derrick Stolee committed Mar 22, 2018 at 13:40 UTC 0aaf05b3bdc1ce48bed9f8dcba54153a2b7cdc09

1 file changed +4 -20

sha1_name.c

+4 -20

@@ -512,32 +512,16 @@ static void find_abbrev_len_for_pack(struct packed_git *p,

512 struct min_abbrev_data *mad)

513 {

514 int match = 0;

515 - uint32_t num, last, first = 0;

515 + uint32_t num, first = 0;

516 struct object_id oid;

517 + const struct object_id *mad_oid;

518

519 if (open_pack_index(p) || !p->num_objects)

520 return;

521

522 num = p->num_objects;

522 - last = num;

523 - while (first < last) {

524 - uint32_t mid = first + (last - first) / 2;

525 - const unsigned char *current;

526 - int cmp;

527 -

528 - current = nth_packed_object_sha1(p, mid);

529 - cmp = hashcmp(mad->oid->hash, current);

530 - if (!cmp) {

531 - match = 1;

532 - first = mid;

533 - break;

534 - }

535 - if (cmp > 0) {

536 - first = mid + 1;

537 - continue;

538 - }

539 - last = mid;

540 - }

523 + mad_oid = mad->oid;

524 + match = bsearch_pack(mad_oid, p, &first);

525

526 /*

527 * first is now the position in the packfile where we would insert