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author | Jeff King <peff@peff.net> | 2021-02-09 05:53:50 -0500 |
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committer | Junio C Hamano <gitster@pobox.com> | 2021-02-11 09:57:55 -0800 |
commit | 16950f8384afa5106b1ce57da07a964c2aaef3f7 (patch) | |
tree | 608e6e56eef19255cfa4637cd54b49af26f4f3e1 /pack-bitmap.c | |
parent | 3803a3a0993045605d7f3db363188ce377e917c8 (diff) | |
download | git-16950f8384afa5106b1ce57da07a964c2aaef3f7.tar.gz |
rev-list: add --disk-usage option for calculating disk usage
It can sometimes be useful to see which refs are contributing to the
overall repository size (e.g., does some branch have a bunch of objects
not found elsewhere in history, which indicates that deleting it would
shrink the size of a clone).
You can find that out by generating a list of objects, getting their
sizes from cat-file, and then summing them, like:
git rev-list --objects --no-object-names main..branch
git cat-file --batch-check='%(objectsize:disk)' |
perl -lne '$total += $_; END { print $total }'
Though note that the caveats from git-cat-file(1) apply here. We "blame"
base objects more than their deltas, even though the relationship could
easily be flipped. Still, it can be a useful rough measure.
But one problem is that it's slow to run. Teaching rev-list to sum up
the sizes can be much faster for two reasons:
1. It skips all of the piping of object names and sizes.
2. If bitmaps are in use, for objects that are in the
bitmapped packfile we can skip the oid_object_info()
lookup entirely, and just ask the revindex for the
on-disk size.
This patch implements a --disk-usage option which produces the same
answer in a fraction of the time. Here are some timings using a clone of
torvalds/linux:
[rev-list piped to cat-file, no bitmaps]
$ time git rev-list --objects --no-object-names --all |
git cat-file --buffer --batch-check='%(objectsize:disk)' |
perl -lne '$total += $_; END { print $total }'
1459938510
real 0m29.635s
user 0m38.003s
sys 0m1.093s
[internal, no bitmaps]
$ time git rev-list --disk-usage --objects --all
1459938510
real 0m31.262s
user 0m30.885s
sys 0m0.376s
Even though the wall-clock time is slightly worse due to parallelism,
notice the CPU savings between the two. We saved 21% of the CPU just by
avoiding the pipes.
But the real win is with bitmaps. If we use them without the new option:
[rev-list piped to cat-file, bitmaps]
$ time git rev-list --objects --no-object-names --all --use-bitmap-index |
git cat-file --batch-check='%(objectsize:disk)' |
perl -lne '$total += $_; END { print $total }'
1459938510
real 0m6.244s
user 0m8.452s
sys 0m0.311s
then we're faster to generate the list of objects, but we still spend a
lot of time piping and looking things up. But if we do both together:
[internal, bitmaps]
$ time git rev-list --disk-usage --objects --all --use-bitmap-index
1459938510
real 0m0.219s
user 0m0.169s
sys 0m0.049s
then we get the same answer much faster.
For "--all", that answer will correspond closely to "du objects/pack",
of course. But we're actually checking reachability here, so we're still
fast when we ask for more interesting things:
$ time git rev-list --disk-usage --use-bitmap-index v5.0..v5.10
374798628
real 0m0.429s
user 0m0.356s
sys 0m0.072s
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'pack-bitmap.c')
-rw-r--r-- | pack-bitmap.c | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/pack-bitmap.c b/pack-bitmap.c index 60fe20fb87..1f69b5fa85 100644 --- a/pack-bitmap.c +++ b/pack-bitmap.c @@ -1430,3 +1430,84 @@ int bitmap_has_oid_in_uninteresting(struct bitmap_index *bitmap_git, return bitmap_git && bitmap_walk_contains(bitmap_git, bitmap_git->haves, oid); } + +static off_t get_disk_usage_for_type(struct bitmap_index *bitmap_git, + enum object_type object_type) +{ + struct bitmap *result = bitmap_git->result; + struct packed_git *pack = bitmap_git->pack; + off_t total = 0; + struct ewah_iterator it; + eword_t filter; + size_t i; + + init_type_iterator(&it, bitmap_git, object_type); + for (i = 0; i < result->word_alloc && + ewah_iterator_next(&filter, &it); i++) { + eword_t word = result->words[i] & filter; + size_t base = (i * BITS_IN_EWORD); + unsigned offset; + + if (!word) + continue; + + for (offset = 0; offset < BITS_IN_EWORD; offset++) { + size_t pos; + + if ((word >> offset) == 0) + break; + + offset += ewah_bit_ctz64(word >> offset); + pos = base + offset; + total += pack_pos_to_offset(pack, pos + 1) - + pack_pos_to_offset(pack, pos); + } + } + + return total; +} + +static off_t get_disk_usage_for_extended(struct bitmap_index *bitmap_git) +{ + struct bitmap *result = bitmap_git->result; + struct packed_git *pack = bitmap_git->pack; + struct eindex *eindex = &bitmap_git->ext_index; + off_t total = 0; + struct object_info oi = OBJECT_INFO_INIT; + off_t object_size; + size_t i; + + oi.disk_sizep = &object_size; + + for (i = 0; i < eindex->count; i++) { + struct object *obj = eindex->objects[i]; + + if (!bitmap_get(result, pack->num_objects + i)) + continue; + + if (oid_object_info_extended(the_repository, &obj->oid, &oi, 0) < 0) + die(_("unable to get disk usage of %s"), + oid_to_hex(&obj->oid)); + + total += object_size; + } + return total; +} + +off_t get_disk_usage_from_bitmap(struct bitmap_index *bitmap_git, + struct rev_info *revs) +{ + off_t total = 0; + + total += get_disk_usage_for_type(bitmap_git, OBJ_COMMIT); + if (revs->tree_objects) + total += get_disk_usage_for_type(bitmap_git, OBJ_TREE); + if (revs->blob_objects) + total += get_disk_usage_for_type(bitmap_git, OBJ_BLOB); + if (revs->tag_objects) + total += get_disk_usage_for_type(bitmap_git, OBJ_TAG); + + total += get_disk_usage_for_extended(bitmap_git); + + return total; +} |