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16950f8384
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>
94 lines
2.9 KiB
C
94 lines
2.9 KiB
C
#ifndef PACK_BITMAP_H
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#define PACK_BITMAP_H
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#include "ewah/ewok.h"
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#include "khash.h"
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#include "pack.h"
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#include "pack-objects.h"
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struct commit;
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struct repository;
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struct rev_info;
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struct list_objects_filter_options;
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static const char BITMAP_IDX_SIGNATURE[] = {'B', 'I', 'T', 'M'};
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struct bitmap_disk_header {
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char magic[ARRAY_SIZE(BITMAP_IDX_SIGNATURE)];
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uint16_t version;
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uint16_t options;
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uint32_t entry_count;
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unsigned char checksum[GIT_MAX_RAWSZ];
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};
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#define NEEDS_BITMAP (1u<<22)
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enum pack_bitmap_opts {
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BITMAP_OPT_FULL_DAG = 1,
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BITMAP_OPT_HASH_CACHE = 4,
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};
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enum pack_bitmap_flags {
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BITMAP_FLAG_REUSE = 0x1
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};
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typedef int (*show_reachable_fn)(
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const struct object_id *oid,
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enum object_type type,
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int flags,
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uint32_t hash,
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struct packed_git *found_pack,
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off_t found_offset);
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struct bitmap_index;
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struct bitmap_index *prepare_bitmap_git(struct repository *r);
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void count_bitmap_commit_list(struct bitmap_index *, uint32_t *commits,
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uint32_t *trees, uint32_t *blobs, uint32_t *tags);
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void traverse_bitmap_commit_list(struct bitmap_index *,
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struct rev_info *revs,
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show_reachable_fn show_reachable);
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void test_bitmap_walk(struct rev_info *revs);
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struct bitmap_index *prepare_bitmap_walk(struct rev_info *revs,
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struct list_objects_filter_options *filter);
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int reuse_partial_packfile_from_bitmap(struct bitmap_index *,
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struct packed_git **packfile,
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uint32_t *entries,
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struct bitmap **reuse_out);
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int rebuild_existing_bitmaps(struct bitmap_index *, struct packing_data *mapping,
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kh_oid_map_t *reused_bitmaps, int show_progress);
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void free_bitmap_index(struct bitmap_index *);
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int bitmap_walk_contains(struct bitmap_index *,
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struct bitmap *bitmap, const struct object_id *oid);
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/*
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* After a traversal has been performed by prepare_bitmap_walk(), this can be
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* queried to see if a particular object was reachable from any of the
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* objects flagged as UNINTERESTING.
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*/
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int bitmap_has_oid_in_uninteresting(struct bitmap_index *, const struct object_id *oid);
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off_t get_disk_usage_from_bitmap(struct bitmap_index *, struct rev_info *);
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void bitmap_writer_show_progress(int show);
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void bitmap_writer_set_checksum(unsigned char *sha1);
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void bitmap_writer_build_type_index(struct packing_data *to_pack,
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struct pack_idx_entry **index,
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uint32_t index_nr);
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uint32_t *create_bitmap_mapping(struct bitmap_index *bitmap_git,
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struct packing_data *mapping);
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int rebuild_bitmap(const uint32_t *reposition,
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struct ewah_bitmap *source,
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struct bitmap *dest);
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struct ewah_bitmap *bitmap_for_commit(struct bitmap_index *bitmap_git,
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struct commit *commit);
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void bitmap_writer_select_commits(struct commit **indexed_commits,
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unsigned int indexed_commits_nr, int max_bitmaps);
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void bitmap_writer_build(struct packing_data *to_pack);
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void bitmap_writer_finish(struct pack_idx_entry **index,
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uint32_t index_nr,
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const char *filename,
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uint16_t options);
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#endif
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