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author | Jeff King <peff@peff.net> | 2021-02-09 05:53:50 -0500 |
---|---|---|
committer | Junio C Hamano <gitster@pobox.com> | 2021-02-11 09:57:55 -0800 |
commit | 16950f8384afa5106b1ce57da07a964c2aaef3f7 (patch) | |
tree | 608e6e56eef19255cfa4637cd54b49af26f4f3e1 /builtin/rev-list.c | |
parent | t: add --no-tag option to test_commit (diff) | |
download | tgif-16950f8384afa5106b1ce57da07a964c2aaef3f7.tar.xz |
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 'builtin/rev-list.c')
-rw-r--r-- | builtin/rev-list.c | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/builtin/rev-list.c b/builtin/rev-list.c index 25c6c3b38d..b4d8ea0a35 100644 --- a/builtin/rev-list.c +++ b/builtin/rev-list.c @@ -80,6 +80,19 @@ static int arg_show_object_names = 1; #define DEFAULT_OIDSET_SIZE (16*1024) +static int show_disk_usage; +static off_t total_disk_usage; + +static off_t get_object_disk_usage(struct object *obj) +{ + off_t size; + struct object_info oi = OBJECT_INFO_INIT; + oi.disk_sizep = &size; + 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)); + return size; +} + static void finish_commit(struct commit *commit); static void show_commit(struct commit *commit, void *data) { @@ -88,6 +101,9 @@ static void show_commit(struct commit *commit, void *data) display_progress(progress, ++progress_counter); + if (show_disk_usage) + total_disk_usage += get_object_disk_usage(&commit->object); + if (info->flags & REV_LIST_QUIET) { finish_commit(commit); return; @@ -258,6 +274,8 @@ static void show_object(struct object *obj, const char *name, void *cb_data) if (finish_object(obj, name, cb_data)) return; display_progress(progress, ++progress_counter); + if (show_disk_usage) + total_disk_usage += get_object_disk_usage(obj); if (info->flags & REV_LIST_QUIET) return; @@ -452,6 +470,23 @@ static int try_bitmap_traversal(struct rev_info *revs, return 0; } +static int try_bitmap_disk_usage(struct rev_info *revs, + struct list_objects_filter_options *filter) +{ + struct bitmap_index *bitmap_git; + + if (!show_disk_usage) + return -1; + + bitmap_git = prepare_bitmap_walk(revs, filter); + if (!bitmap_git) + return -1; + + printf("%"PRIuMAX"\n", + (uintmax_t)get_disk_usage_from_bitmap(bitmap_git, revs)); + return 0; +} + int cmd_rev_list(int argc, const char **argv, const char *prefix) { struct rev_info revs; @@ -584,6 +619,12 @@ int cmd_rev_list(int argc, const char **argv, const char *prefix) continue; } + if (!strcmp(arg, "--disk-usage")) { + show_disk_usage = 1; + info.flags |= REV_LIST_QUIET; + continue; + } + usage(rev_list_usage); } @@ -626,6 +667,8 @@ int cmd_rev_list(int argc, const char **argv, const char *prefix) if (use_bitmap_index) { if (!try_bitmap_count(&revs, &filter_options)) return 0; + if (!try_bitmap_disk_usage(&revs, &filter_options)) + return 0; if (!try_bitmap_traversal(&revs, &filter_options)) return 0; } @@ -690,5 +733,8 @@ int cmd_rev_list(int argc, const char **argv, const char *prefix) printf("%d\n", revs.count_left + revs.count_right); } + if (show_disk_usage) + printf("%"PRIuMAX"\n", (uintmax_t)total_disk_usage); + return 0; } |