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540cdc11ad
When preparing the bitmap walk, we first establish the set of of have and want objects by iterating over the set of pending objects: if an object is marked as uninteresting, it's declared as an object we already have, otherwise as an object we want. These two sets are then used to compute which transitively referenced objects we need to obtain. One special case here are tag objects: when a tag is requested, we resolve it to its first not-tag object and add both resolved objects as well as the tag itself into either the have or want set. Given that the uninteresting-property always propagates to referenced objects, it is clear that if the tag is uninteresting, so are its children and vice versa. But we fail to propagate the flag, which effectively means that referenced objects will always be interesting except for the case where they have already been marked as uninteresting explicitly. This mislabeling does not impact correctness: we now have it in our "wants" set, and given that we later do an `AND NOT` of the bitmaps of "wants" and "haves" sets it is clear that the result must be the same. But we now start to needlessly traverse the tag's referenced objects in case it is uninteresting, even though we know that each referenced object will be uninteresting anyway. In the worst case, this can lead to a complete graph walk just to establish that we do not care for any object. Fix the issue by propagating the `UNINTERESTING` flag to pointees of tag objects and add a benchmark with negative revisions to p5310. This shows some nice performance benefits, tested with linux.git: Test HEAD~ HEAD --------------------------------------------------------------------------------------------------------------- 5310.3: repack to disk 193.18(181.46+16.42) 194.61(183.41+15.83) +0.7% 5310.4: simulated clone 25.93(24.88+1.05) 25.81(24.73+1.08) -0.5% 5310.5: simulated fetch 2.64(5.30+0.69) 2.59(5.16+0.65) -1.9% 5310.6: pack to file (bitmap) 58.75(57.56+6.30) 58.29(57.61+5.73) -0.8% 5310.7: rev-list (commits) 1.45(1.18+0.26) 1.46(1.22+0.24) +0.7% 5310.8: rev-list (objects) 15.35(14.22+1.13) 15.30(14.23+1.07) -0.3% 5310.9: rev-list with tag negated via --not --all (objects) 22.49(20.93+1.56) 0.11(0.09+0.01) -99.5% 5310.10: rev-list with negative tag (objects) 0.61(0.44+0.16) 0.51(0.35+0.16) -16.4% 5310.11: rev-list count with blob:none 12.15(11.19+0.96) 12.18(11.19+0.99) +0.2% 5310.12: rev-list count with blob:limit=1k 17.77(15.71+2.06) 17.75(15.63+2.12) -0.1% 5310.13: rev-list count with tree:0 1.69(1.31+0.38) 1.68(1.28+0.39) -0.6% 5310.14: simulated partial clone 20.14(19.15+0.98) 19.98(18.93+1.05) -0.8% 5310.16: clone (partial bitmap) 12.78(13.89+1.07) 12.72(13.99+1.01) -0.5% 5310.17: pack to file (partial bitmap) 42.07(45.44+2.72) 41.44(44.66+2.80) -1.5% 5310.18: rev-list with tree filter (partial bitmap) 0.44(0.29+0.15) 0.46(0.32+0.14) +4.5% While most benchmarks are probably in the range of noise, the newly added 5310.9 and 5310.10 benchmarks consistenly perform better. Signed-off-by: Patrick Steinhardt <ps@pks.im>. Signed-off-by: Junio C Hamano <gitster@pobox.com>
114 lines
3.0 KiB
Bash
Executable File
114 lines
3.0 KiB
Bash
Executable File
#!/bin/sh
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test_description='Tests pack performance using bitmaps'
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. ./perf-lib.sh
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test_perf_large_repo
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# note that we do everything through config,
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# since we want to be able to compare bitmap-aware
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# git versus non-bitmap git
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#
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# We intentionally use the deprecated pack.writebitmaps
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# config so that we can test against older versions of git.
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test_expect_success 'setup bitmap config' '
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git config pack.writebitmaps true
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'
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# we need to create the tag up front such that it is covered by the repack and
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# thus by generated bitmaps.
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test_expect_success 'create tags' '
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git tag --message="tag pointing to HEAD" perf-tag HEAD
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'
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test_perf 'repack to disk' '
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git repack -ad
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'
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test_perf 'simulated clone' '
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git pack-objects --stdout --all </dev/null >/dev/null
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'
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test_perf 'simulated fetch' '
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have=$(git rev-list HEAD~100 -1) &&
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{
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echo HEAD &&
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echo ^$have
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} | git pack-objects --revs --stdout >/dev/null
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'
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test_perf 'pack to file (bitmap)' '
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git pack-objects --use-bitmap-index --all pack1b </dev/null >/dev/null
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'
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test_perf 'rev-list (commits)' '
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git rev-list --all --use-bitmap-index >/dev/null
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'
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test_perf 'rev-list (objects)' '
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git rev-list --all --use-bitmap-index --objects >/dev/null
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'
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test_perf 'rev-list with tag negated via --not --all (objects)' '
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git rev-list perf-tag --not --all --use-bitmap-index --objects >/dev/null
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'
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test_perf 'rev-list with negative tag (objects)' '
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git rev-list HEAD --not perf-tag --use-bitmap-index --objects >/dev/null
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'
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test_perf 'rev-list count with blob:none' '
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git rev-list --use-bitmap-index --count --objects --all \
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--filter=blob:none >/dev/null
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'
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test_perf 'rev-list count with blob:limit=1k' '
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git rev-list --use-bitmap-index --count --objects --all \
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--filter=blob:limit=1k >/dev/null
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'
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test_perf 'rev-list count with tree:0' '
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git rev-list --use-bitmap-index --count --objects --all \
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--filter=tree:0 >/dev/null
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'
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test_perf 'simulated partial clone' '
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git pack-objects --stdout --all --filter=blob:none </dev/null >/dev/null
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'
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test_expect_success 'create partial bitmap state' '
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# pick a commit to represent the repo tip in the past
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cutoff=$(git rev-list HEAD~100 -1) &&
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orig_tip=$(git rev-parse HEAD) &&
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# now kill off all of the refs and pretend we had
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# just the one tip
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rm -rf .git/logs .git/refs/* .git/packed-refs &&
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git update-ref HEAD $cutoff &&
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# and then repack, which will leave us with a nice
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# big bitmap pack of the "old" history, and all of
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# the new history will be loose, as if it had been pushed
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# up incrementally and exploded via unpack-objects
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git repack -Ad &&
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# and now restore our original tip, as if the pushes
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# had happened
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git update-ref HEAD $orig_tip
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'
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test_perf 'clone (partial bitmap)' '
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git pack-objects --stdout --all </dev/null >/dev/null
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'
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test_perf 'pack to file (partial bitmap)' '
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git pack-objects --use-bitmap-index --all pack2b </dev/null >/dev/null
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'
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test_perf 'rev-list with tree filter (partial bitmap)' '
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git rev-list --use-bitmap-index --count --objects --all \
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--filter=tree:0 >/dev/null
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'
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test_done
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