Re: [PATCH 5/7] p5313: add size comparison test

> From: Derrick Stolee <stolee@gmail.com>
>
> As custom options are added to 'git pack-objects' and 'git repack' to
> adjust how compression is done, use this new performance test script to
> demonstrate their effectiveness in performance and size.

> In the case of the Git repository, these numbers show some of the issues
> with this approach:
>
> [...]
>
> The thin pack that simulates a push is much worse with --full-name-hash
> in this case. The name hash values are doing a lot to assist with delta
> bases, it seems. The big pack and shallow clone cases are slightly worse
> with the --full-name-hash option. Only the full repack gains some
> benefits in size.

> ---
>  t/perf/p5313-pack-objects.sh | 94 ++++++++++++++++++++++++++++++++++++
>  1 file changed, 94 insertions(+)
>  create mode 100755 t/perf/p5313-pack-objects.sh
>
> diff --git a/t/perf/p5313-pack-objects.sh b/t/perf/p5313-pack-objects.sh
> new file mode 100755
> index 00000000000..dfa29695315
> --- /dev/null
> +++ b/t/perf/p5313-pack-objects.sh
> @@ -0,0 +1,94 @@
> +#!/bin/sh
> +
> +test_description='Tests pack performance using bitmaps'
> +. ./perf-lib.sh
> +
> +GIT_TEST_PASSING_SANITIZE_LEAK=0
> +export GIT_TEST_PASSING_SANITIZE_LEAK
> +
> +test_perf_large_repo
> +
> +test_expect_success 'create rev input' '
> +	cat >in-thin <<-EOF &&
> +	$(git rev-parse HEAD)
> +	^$(git rev-parse HEAD~1)
> +	EOF
> +
> +	cat >in-big <<-EOF &&
> +	$(git rev-parse HEAD)
> +	^$(git rev-parse HEAD~1000)
> +	EOF
> +
> +	cat >in-shallow <<-EOF
> +	$(git rev-parse HEAD)
> +	--shallow $(git rev-parse HEAD)
> +	EOF
> +'

> +
> +test_perf 'thin pack' '
> +	git pack-objects --thin --stdout --revs --sparse  <in-thin >out
> +'
> +
> +test_size 'thin pack size' '
> +	test_file_size out
> +'

> +test_perf 'thin pack with --full-name-hash' '
> +	git pack-objects --thin --stdout --revs --sparse --full-name-hash <in-thin >out
> +'
> +
> +test_size 'thin pack size with --full-name-hash' '
> +	test_file_size out
> +'
> +
> +test_perf 'big pack' '
> +	git pack-objects --stdout --revs --sparse  <in-big >out
> +'
> +
> +test_size 'big pack size' '
> +	test_file_size out
> +'
> +
> +test_perf 'big pack with --full-name-hash' '
> +	git pack-objects --stdout --revs --sparse --full-name-hash <in-big >out
> +'
> +
> +test_size 'big pack size with --full-name-hash' '
> +	test_file_size out
> +'
> +
> +test_perf 'shallow fetch pack' '
> +	git pack-objects --stdout --revs --sparse --shallow <in-shallow >out
> +'
> +
> +test_size 'shallow pack size' '
> +	test_file_size out
> +'
> +
> +test_perf 'shallow pack with --full-name-hash' '
> +	git pack-objects --stdout --revs --sparse --shallow --full-name-hash <in-shallow >out
> +'
> +
> +test_size 'shallow pack size with --full-name-hash' '
> +	test_file_size out
> +'
> +
> +test_perf 'repack' '
> +	git repack -adf
> +'
> +
> +test_size 'repack size' '
> +	pack=$(ls .git/objects/pack/pack-*.pack) &&
> +	test_file_size "$pack"