Re: [PATCH v2 2/2] blame: enable and test the sparse index
- From
Taylor Blau <me@ttaylorr.com>
- Date
- Oct 25, 2021, 20:53 UTC
- Message-ID
- <YXcZPxYlRLEEwU16@nand.local>
- In-Reply-To
- <a0b6a152c754862323e9a5b89ad43ab34b6548f7.1634332836.git.gitgitgadget@gmail.com>
On Fri, Oct 15, 2021 at 09:20:35PM +0000, Lessley Dennington via GitGitGadget wrote:
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> From: Lessley Dennington <lessleydennington@gmail.com> > > Enable the sparse index for the 'git blame' command. The index was already > not expanded with this command, so the most interesting thing to do is to > add tests that verify that 'git blame' behaves correctly when the sparse > index is enabled and that its performance improves. More specifically, these > cases are: > > 1. The index is not expanded for 'blame' when given paths in the sparse > checkout cone at multiple levels. > > 2. Performance measurably improves for 'blame' with sparse index when given > paths in the sparse checkout cone at multiple levels. > > The `p2000` tests demonstrate a ~60% execution time reduction when running > 'blame' for a file two levels deep and and a ~30% execution time reduction > for a file three levels deep.
Eek. What's eating up the other 30% when we have to open up another layer of trees?
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> > Test before after > ---------------------------------------------------------------- > 2000.62: git blame f2/f4/a (full-v3) 0.31 0.32 +3.2% > 2000.63: git blame f2/f4/a (full-v4) 0.29 0.31 +6.9% > 2000.64: git blame f2/f4/a (sparse-v3) 0.55 0.23 -58.2% > 2000.65: git blame f2/f4/a (sparse-v4) 0.57 0.23 -59.6% > 2000.66: git blame f2/f4/f3/a (full-v3) 0.77 0.85 +10.4% > 2000.67: git blame f2/f4/f3/a (full-v4) 0.78 0.81 +3.8% > 2000.68: git blame f2/f4/f3/a (sparse-v3) 1.07 0.72 -32.7% > 2000.99: git blame f2/f4/f3/a (sparse-v4) 1.05 0.73 -30.5% > > We do not include paths outside the sparse checkout cone because blame > currently does not support blaming files outside of the sparse definition. > Attempting to do so fails with the following error: > > fatal: no such path '<path outside sparse definition>' in HEAD.
Small nit; this error message should be indented with a couple of space characters to indicate that it's the output of running Git instead of part of your patch message. Not worth a reroll on its own, but something to keep in mind for your many future patches :).
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> > Signed-off-by: Lessley Dennington <lessleydennington@gmail.com> > --- > builtin/blame.c | 3 +++ > t/perf/p2000-sparse-operations.sh | 2 ++ > t/t1092-sparse-checkout-compatibility.sh | 24 +++++++++++++++++------- > 3 files changed, 22 insertions(+), 7 deletions(-) > > diff --git a/builtin/blame.c b/builtin/blame.c > index 641523ff9af..af3d81e2bd4 100644 > --- a/builtin/blame.c > +++ b/builtin/blame.c > @@ -902,6 +902,9 @@ int cmd_blame(int argc, const char **argv, const char *prefix) > long anchor; > const int hexsz = the_hash_algo->hexsz; > > + prepare_repo_settings(the_repository); > + the_repository->settings.command_requires_full_index = 0; > +
By now we're quite used to seeing this ;). Makes sense to me.
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> setup_default_color_by_age(); > git_config(git_blame_config, &output_option); > repo_init_revisions(the_repository, &revs, NULL); > diff --git a/t/perf/p2000-sparse-operations.sh b/t/perf/p2000-sparse-operations.sh > index bff93f16e93..9ac76a049b8 100755 > --- a/t/perf/p2000-sparse-operations.sh > +++ b/t/perf/p2000-sparse-operations.sh > @@ -115,5 +115,7 @@ test_perf_on_all git reset --hard > test_perf_on_all git reset -- does-not-exist > test_perf_on_all git diff > test_perf_on_all git diff --staged > +test_perf_on_all git blame $SPARSE_CONE/a > +test_perf_on_all git blame $SPARSE_CONE/f3/a
Good.
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> test_done > diff --git a/t/t1092-sparse-checkout-compatibility.sh b/t/t1092-sparse-checkout-compatibility.sh > index e5d15be9d45..960ccf2d150 100755 > --- a/t/t1092-sparse-checkout-compatibility.sh > +++ b/t/t1092-sparse-checkout-compatibility.sh > @@ -488,15 +488,16 @@ test_expect_success 'blame with pathspec inside sparse definition' ' > test_all_match git blame deep/deeper1/deepest/a > ' > > -# TODO: blame currently does not support blaming files outside of the > -# sparse definition. It complains that the file doesn't exist locally. > -test_expect_failure 'blame with pathspec outside sparse definition' ' > +# Blame does not support blaming files outside of the sparse > +# definition, so we verify this scenario. > +test_expect_success 'blame with pathspec outside sparse definition' ' > init_repos && > > - test_all_match git blame folder1/a && > - test_all_match git blame folder2/a && > - test_all_match git blame deep/deeper2/a && > - test_all_match git blame deep/deeper2/deepest/a > + test_sparse_match git sparse-checkout set && > + test_sparse_match test_must_fail git blame folder1/a && > + test_sparse_match test_must_fail git blame folder2/a && > + test_sparse_match test_must_fail git blame deep/deeper2/a && > + test_sparse_match test_must_fail git blame deep/deeper2/deepest/a > '
test_must_fail used to allow for segfaults, but doesn't these days. So this is a good test of "it should fail in sparse checkouts but not crash", although I think it would be good to ensure that it's failing in the way you expect (i.e., by checking that stderr contains "no such path <xyz> in HEAD").
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> > test_expect_success 'checkout and reset (mixed)' ' > @@ -874,6 +875,15 @@ test_expect_success 'sparse-index is not expanded: merge conflict in cone' ' > ) > ' > > +test_expect_success 'sparse index is not expanded: blame' ' > + init_repos && > + > + ensure_not_expanded blame a && > + ensure_not_expanded blame deep/a && > + ensure_not_expanded blame deep/deeper1/a && > + ensure_not_expanded blame deep/deeper1/deepest/a > +'
Makes sense. Probably just one of these is necessary, but I haven't looked into init_repos (or the "setup" test) enough to know for sure. Either way, not worth changing.
Thanks, Taylor