From 16950f8384afa5106b1ce57da07a964c2aaef3f7 Mon Sep 17 00:00:00 2001 From: Jeff King Date: Tue, 9 Feb 2021 05:53:50 -0500 Subject: 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 Signed-off-by: Junio C Hamano --- builtin/rev-list.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) (limited to 'builtin/rev-list.c') 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; } -- cgit 1.2.3-korg