[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>
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 t/perf/p2000-sparse-operations.sh | 1 +
 1 file changed, 1 insertion(+)