Re: [PATCH 3/3] p2000: add performance test for 'git add -p'

>
> From: Derrick Stolee <stolee@gmail.com>
>
> The previous two changes contributed performance improvements to 'git
> apply' and 'git add -p' when using a sparse index. Add a performance
> test to demonstrate this (and to help validate that performance remains
> good in the future).
>
> In the truncated test output below, we see that the full checkout
> performance changes within noise expectations, but the sparse index
> cases improve 33% and then 96%.
>
>                       HEAD~3     HEAD~2         HEAD~1
> ---------------------------------------------------------
> 2000.118: (full-v3)     0.80   0.84 +5.0%     0.84  +5.0%
> 2000.119: (full-v4)     0.76   0.79 +3.9%     0.80  +5.3%
> 2000.120: (sparse-v3)   2.09   1.39 -33.5%    0.07 -96.7%
> 2000.121: (sparse-v4)   2.09   1.39 -33.5%    0.07 -96.7%
>
> It is worth noting that if our test was more involved and had multiple
> hunks to evaluate, then the time spent in 'git apply' would dominate due
> to multiple index loads and writes. As it stands, we need the sparse
> index improvement in 'git add -p' itself to confirm this performance
> improvement.
>
> Since the change for 'git add -i' is identical, we avoid a second test
> case for that similar operation.
>
> Signed-off-by: Derrick Stolee <stolee@gmail.com>
> ---
>  t/perf/p2000-sparse-operations.sh | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/t/perf/p2000-sparse-operations.sh b/t/perf/p2000-sparse-operations.sh
> index 39e92b084143..3da6ae59c000 100755
> --- a/t/perf/p2000-sparse-operations.sh
> +++ b/t/perf/p2000-sparse-operations.sh
> @@ -135,5 +135,6 @@ test_perf_on_all git diff-tree HEAD
>  test_perf_on_all git diff-tree HEAD -- $SPARSE_CONE/a
>  test_perf_on_all "git worktree add ../temp && git worktree remove ../temp"
>  test_perf_on_all git check-attr -a -- $SPARSE_CONE/a
> +test_perf_on_all 'echo >>a && test_write_lines y | git add -p'
>
>  test_done
> --
> gitgitgadget