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builtin/pack-objects.c: rewrite honor-pack-keep logic 

Now that we have find_kept_pack_entry(), we don't have to manually keep
hunting through every pack to find a possible "kept" duplicate of the
object. This should be faster, assuming only a portion of your total
packs are actually kept.

Note that we have to re-order the logic a bit here; we can deal with the
disqualifying situations first (e.g., finding the object in a non-local
pack with --local), then "kept" situation(s), and then just fall back to
other "--local" conditions.

Here are the results from p5303 (measurements again taken on the
kernel):

  Test                                        HEAD^                   HEAD
  -----------------------------------------------------------------------------------------------
  5303.5: repack (1)                          57.26(54.59+10.84)      57.34(54.66+10.88) +0.1%
  5303.6: repack with kept (1)                57.33(54.80+10.51)      57.38(54.83+10.49) +0.1%
  5303.11: repack (50)                        71.54(88.57+4.84)       71.70(88.99+4.74) +0.2%
  5303.12: repack with kept (50)              85.12(102.05+4.94)      72.58(89.61+4.78) -14.7%
  5303.17: repack (1000)                      216.87(490.79+14.57)    217.19(491.72+14.25) +0.1%
  5303.18: repack with kept (1000)            665.63(938.87+15.76)    246.12(520.07+14.93) -63.0%

and the --stdin-packs timings:

  5303.7: repack with --stdin-packs (1)       0.01(0.01+0.00)         0.00(0.00+0.00) -100.0%
  5303.13: repack with --stdin-packs (50)     3.53(12.07+0.24)        3.43(11.75+0.24) -2.8%
  5303.19: repack with --stdin-packs (1000)   195.83(371.82+8.10)     130.50(307.15+7.66) -33.4%

So our repack with an empty .keep pack is roughly as fast as one without
a .keep pack up to 50 packs. But the --stdin-packs case scales a little
better, too.

Notably, it is faster than a repack of the same size and a kept pack. It
looks at fewer objects, of course, but the penalty for looking at many
packs isn't as costly.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Jeff King 2021-02-22 21:25:20 -05:00 committed by Junio C Hamano
parent fbf20aeeef
commit 6325da14af
1 changed files with 76 additions and 51 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

127
builtin/pack-objects.c
View File

@ -1188,7 +1188,8 @@ static int have_duplicate_entry(const struct object_id *oid,
return 1;
}
static int want_found_object(int exclude, struct packed_git *p)
static int want_found_object(const struct object_id *oid, int exclude,
struct packed_git *p)
{
if (exclude)
return 1;
@ -1204,27 +1205,82 @@ static int want_found_object(int exclude, struct packed_git *p)
* make sure no copy of this object appears in _any_ pack that makes us
* to omit the object, so we need to check all the packs.
*
* We can however first check whether these options can possible matter;
* We can however first check whether these options can possibly matter;
* if they do not matter we know we want the object in generated pack.
* Otherwise, we signal "-1" at the end to tell the caller that we do
* not know either way, and it needs to check more packs.
*/
if (!ignore_packed_keep_on_disk &&
!ignore_packed_keep_in_core &&
(!local || !have_non_local_packs))
return 1;
/*
* Objects in packs borrowed from elsewhere are discarded regardless of
* if they appear in other packs that weren't borrowed.
*/
if (local && !p->pack_local)
return 0;
if (p->pack_local &&
((ignore_packed_keep_on_disk && p->pack_keep) ||
(ignore_packed_keep_in_core && p->pack_keep_in_core)))
return 0;
/*
* Then handle .keep first, as we have a fast(er) path there.
*/
if (ignore_packed_keep_on_disk || ignore_packed_keep_in_core) {
/*
* Set the flags for the kept-pack cache to be the ones we want
* to ignore.
*
* That is, if we are ignoring objects in on-disk keep packs,
* then we want to search through the on-disk keep and ignore
* the in-core ones.
*/
unsigned flags = 0;
if (ignore_packed_keep_on_disk)
flags |= ON_DISK_KEEP_PACKS;
if (ignore_packed_keep_in_core)
flags |= IN_CORE_KEEP_PACKS;
if (ignore_packed_keep_on_disk && p->pack_keep)
return 0;
if (ignore_packed_keep_in_core && p->pack_keep_in_core)
return 0;
if (has_object_kept_pack(oid, flags))
return 0;
}
/*
* At this point we know definitively that either we don't care about
* keep-packs, or the object is not in one. Keep checking other
* conditions...
*/
if (!local || !have_non_local_packs)
return 1;
/* we don't know yet; keep looking for more packs */
return -1;
}
static int want_object_in_pack_one(struct packed_git *p,
const struct object_id *oid,
int exclude,
struct packed_git **found_pack,
off_t *found_offset)
{
off_t offset;
if (p == *found_pack)
offset = *found_offset;
else
offset = find_pack_entry_one(oid->hash, p);
if (offset) {
if (!*found_pack) {
if (!is_pack_valid(p))
return -1;
*found_offset = offset;
*found_pack = p;
}
return want_found_object(oid, exclude, p);
}
return -1;
}
/*
* Check whether we want the object in the pack (e.g., we do not want
* objects found in non-local stores if the "--local" option was used).
@ -1252,7 +1308,7 @@ static int want_object_in_pack(const struct object_id *oid,
* are present we will determine the answer right now.
*/
if (*found_pack) {
want = want_found_object(exclude, *found_pack);
want = want_found_object(oid, exclude, *found_pack);
if (want != -1)
return want;
}
@ -1260,51 +1316,20 @@ static int want_object_in_pack(const struct object_id *oid,
for (m = get_multi_pack_index(the_repository); m; m = m->next) {
struct pack_entry e;
if (fill_midx_entry(the_repository, oid, &e, m)) {
struct packed_git *p = e.p;
off_t offset;
if (p == *found_pack)
offset = *found_offset;
else
offset = find_pack_entry_one(oid->hash, p);
if (offset) {
if (!*found_pack) {
if (!is_pack_valid(p))
continue;
*found_offset = offset;
*found_pack = p;
}
want = want_found_object(exclude, p);
if (want != -1)
return want;
}
want = want_object_in_pack_one(e.p, oid, exclude, found_pack, found_offset);
if (want != -1)
return want;
}
}
list_for_each(pos, get_packed_git_mru(the_repository)) {
struct packed_git *p = list_entry(pos, struct packed_git, mru);
off_t offset;
if (p == *found_pack)
offset = *found_offset;
else
offset = find_pack_entry_one(oid->hash, p);
if (offset) {
if (!*found_pack) {
if (!is_pack_valid(p))
continue;
*found_offset = offset;
*found_pack = p;
}
want = want_found_object(exclude, p);
if (!exclude && want > 0)
list_move(&p->mru,
get_packed_git_mru(the_repository));
if (want != -1)
return want;
}
want = want_object_in_pack_one(p, oid, exclude, found_pack, found_offset);
if (!exclude && want > 0)
list_move(&p->mru,
get_packed_git_mru(the_repository));
if (want != -1)
return want;
}
if (uri_protocols.nr) {