git-commit-vandalism/t/perf/p5326-multi-pack-bitmaps.sh
Abhradeep Chakraborty 761416ef91 bitmap-lookup-table: add performance tests for lookup table
Add performance tests to verify the performance of lookup table.
`p5310-pack-bitmaps.sh` contain tests with and without lookup table.
`p5312-pack-bitmaps-revs.sh` contain same tests with and without
lookup table but with `pack.writeReverseIndex` enabled.

Lookup table makes Git run faster in most of the cases. Below is the
result of `t/perf/p5310-pack-bitmaps.sh`.`perf/p5326-multi-pack-bitmaps.sh`
gives similar result. The repository used in the test is linux kernel.

Test                                                    this tree
-----------------------------------------------------------------------
5310.4: enable lookup table: false                    0.01(0.00+0.00)
5310.5: repack to disk                                320.89(230.20+23.45)
5310.6: simulated clone                               14.04(5.78+1.79)
5310.7: simulated fetch                               1.95(3.05+0.20)
5310.8: pack to file (bitmap)                         44.73(20.55+7.45)
5310.9: rev-list (commits)                            0.78(0.46+0.10)
5310.10: rev-list (objects)                           4.07(3.97+0.08)
5310.11: rev-list with tag negated via --not          0.06(0.02+0.03)
         --all (objects)
5310.12: rev-list with negative tag (objects)         0.21(0.15+0.05)
5310.13: rev-list count with blob:none                0.24(0.17+0.06)
5310.14: rev-list count with blob:limit=1k            7.07(5.92+0.48)
5310.15: rev-list count with tree:0                   0.25(0.17+0.07)
5310.16: simulated partial clone                      5.67(3.28+0.64)
5310.18: clone (partial bitmap)                       16.05(8.34+1.86)
5310.19: pack to file (partial bitmap)                59.76(27.22+7.43)
5310.20: rev-list with tree filter (partial bitmap)   0.90(0.18+0.16)
5310.24: enable lookup table: true                    0.01(0.00+0.00)
5310.25: repack to disk                               319.73(229.30+23.01)
5310.26: simulated clone                              13.69(5.72+1.78)
5310.27: simulated fetch                              1.84(3.02+0.16)
5310.28: pack to file (bitmap)                        45.63(20.67+7.50)
5310.29: rev-list (commits)                           0.56(0.39+0.8)
5310.30: rev-list (objects)                           3.77(3.74+0.08)
5310.31: rev-list with tag negated via --not          0.05(0.02+0.03)
         --all (objects)
5310.32: rev-list with negative tag (objects)         0.21(0.15+0.05)
5310.33: rev-list count with blob:none                0.23(0.17+0.05)
5310.34: rev-list count with blob:limit=1k            6.65(5.72+0.40)
5310.35: rev-list count with tree:0                   0.23(0.16+0.06)
5310.36: simulated partial clone                      5.57(3.26+0.59)
5310.38: clone (partial bitmap)                       15.89(8.39+1.84)
5310.39: pack to file (partial bitmap)                58.32(27.55+7.47)
5310.40: rev-list with tree filter (partial bitmap)   0.73(0.18+0.15)

Test 4-15 are tested without using lookup table. Same tests are
repeated in 16-30 (using lookup table).

Mentored-by: Taylor Blau <me@ttaylorr.com>
Co-Mentored-by: Kaartic Sivaraam <kaartic.sivaraam@gmail.com>
Signed-off-by: Abhradeep Chakraborty <chakrabortyabhradeep79@gmail.com>
Reviewed-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-08-26 10:14:02 -07:00

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#!/bin/sh
test_description='Tests performance using midx bitmaps'
. ./perf-lib.sh
. "${TEST_DIRECTORY}/perf/lib-bitmap.sh"
test_bitmap () {
local enabled="$1"
test_expect_success "remove existing repo (lookup=$enabled)" '
rm -fr * .git
'
test_perf_large_repo
# we need to create the tag up front such that it is covered by the repack and
# thus by generated bitmaps.
test_expect_success 'create tags' '
git tag --message="tag pointing to HEAD" perf-tag HEAD
'
test_expect_success "use lookup table: $enabled" '
git config pack.writeBitmapLookupTable '"$enabled"'
'
test_expect_success "start with bitmapped pack (lookup=$enabled)" '
git repack -adb
'
test_perf "setup multi-pack index (lookup=$enabled)" '
git multi-pack-index write --bitmap
'
test_expect_success "drop pack bitmap (lookup=$enabled)" '
rm -f .git/objects/pack/pack-*.bitmap
'
test_full_bitmap
test_expect_success "create partial bitmap state (lookup=$enabled)" '
# pick a commit to represent the repo tip in the past
cutoff=$(git rev-list HEAD~100 -1) &&
orig_tip=$(git rev-parse HEAD) &&
# now pretend we have just one tip
rm -rf .git/logs .git/refs/* .git/packed-refs &&
git update-ref HEAD $cutoff &&
# and then repack, which will leave us with a nice
# big bitmap pack of the "old" history, and all of
# the new history will be loose, as if it had been pushed
# up incrementally and exploded via unpack-objects
git repack -Ad &&
git multi-pack-index write --bitmap &&
# and now restore our original tip, as if the pushes
# had happened
git update-ref HEAD $orig_tip
'
test_partial_bitmap
}
test_bitmap false
test_bitmap true
test_done