diff: enable and test the sparse index #419

ldennington · 2021-09-01T21:55:58Z

Enable the sparse index within the 'git diff' command. Its implementation
already safely integrates with the sparse index because it shares code with the
'git status' and 'git checkout' commands that were already integrated. The most
interesting thing to do is to add tests that verify that 'git diff' behaves
correctly when the sparse index is enabled. These cases are...

The index is not expanded for diff and diff --staged (which both
involve reading from the index).
diff and diff --staged behave the same in full
checkout, sparse checkout, and sparse index repositories in the following
partially-staged scenarios (i.e. the index, HEAD, and working directory
differ at a given path):
1. Path is within sparse-checkout cone.
2. Path is outside sparse-checkout cone.
3. A merge conflict exists for paths outside sparse-checkout cone.

Signed-off-by: Lessley Dennington lessleydennington@gmail.com

t/t1092-sparse-checkout-compatibility.sh

derrickstolee · 2021-09-07T15:32:15Z

After reviewing #417, I decided to add ensure_full_index to this
initial commit in an attempt to maintain current behavior. However,
as I started building and testing with and without this update, I
noticed unexpected results.

The ensure_not_expanded tests I added are passing with
ensure_full_index both enabled and disabled. That felt wrong, so I
used TRACE2 to try and understand what was happening and have attached
the results below.

Have these concerns been fully resolved?

On the bright side, however, it doesn't look as though ensure_full_index
is ever being called. I recognize my lack of knowledge wrt cache-tree
and read-cache may be the reason I'm unsure what the correct path
forward is. In light of this, any guidance is appreciated.

I think it is completely reasonable to expect no proactive work in the
Git code to make it not expand, since git diff is doing things that
already exist within git status and git checkout. The real work for
this builtin is all in the testing: how sure are we that this will work
correctly and quickly in the presence of a sparse index? What about
strange situations like staged changes outside the cone? Merge
conflicts outside the cone? A lot of these situations are tested in the
t1092 test script, so maybe it is enough to sprinkle some lines into
the existing tests. Lines such as:

test_all_match git diff &&

or

test_all_match git diff --staged &&

t/t1092-sparse-checkout-compatibility.sh

derrickstolee

Just a nit and a commit message rewrite and we are good to go!

t/t1092-sparse-checkout-compatibility.sh

builtin/diff.c

vdye

I just had one comment on the test structure - otherwise looks good!

t/t1092-sparse-checkout-compatibility.sh

Enable the sparse index within the 'git diff' command. Its implementation already safely integrates with the sparse index because it shares code with the 'git status' and 'git checkout' commands that were already integrated. The most interesting thing to do is to add tests that verify that 'git diff' behaves correctly when the sparse index is enabled. These cases are... 1. The index is not expanded for `diff` and `diff --staged` (which both involve reading from the index). 2. `diff` and `diff --staged` behave the same in full checkout, sparse checkout, and sparse index repositories in the following partially-staged scenarios (i.e. the index, HEAD, and working directory differ at a given path): 1. Path is within sparse-checkout cone. 2. Path is outside sparse-checkout cone. 3. A merge conflict exists for paths outside sparse-checkout cone. Signed-off-by: Lessley Dennington <lessleydennington@gmail.com>

One thing I forgot when talking about the sparse index is that we have a performance test: `t/perf/p2000-sparse-operations.sh`. This test wasn't helpful for commands like `git merge` that need a particular set of input, but work for more read-only operations. Here is a quick demonstration of how this performance test works so we could have a definitive measure of how your previous updates improved performance. To get these results, I ran the following command in `t/perf`: ``` ./run 4bcd533 f9255a5 f28fc01 b713582 -- p2000-sparse-operations.sh ``` The short-shas correspond to the merge commits for these PRs: * #410 * #421 * #417 * #419 The test takes a copy of the Git repository and creates several copies within a nested directory heirarchy. ``` Test 4bcd533 f9255a5 f28fc01 b713582 ------------------------------------------------------------------------------------------------------------------------------------------------- 2000.2: git status (full-v3) 0.19(0.15+0.05) 0.19(0.16+0.05) +0.0% 0.20(0.18+0.03) +5.3% 0.19(0.17+0.04) +0.0% 2000.3: git status (full-v4) 0.20(0.18+0.04) 0.19(0.15+0.06) -5.0% 0.21(0.18+0.05) +5.0% 0.18(0.18+0.02) -10.0% 2000.4: git status (sparse-v3) 0.04(0.04+0.04) 0.05(0.07+0.04) +25.0% 0.04(0.04+0.05) +0.0% 0.04(0.06+0.04) +0.0% 2000.5: git status (sparse-v4) 0.04(0.03+0.06) 0.04(0.05+0.05) +0.0% 0.05(0.05+0.04) +25.0% 0.05(0.06+0.04) +25.0% 2000.6: git add -A (full-v3) 0.36(0.29+0.05) 0.38(0.28+0.07) +5.6% 0.36(0.31+0.05) +0.0% 0.37(0.31+0.05) +2.8% 2000.7: git add -A (full-v4) 0.34(0.27+0.06) 0.34(0.29+0.05) +0.0% 0.34(0.29+0.04) +0.0% 0.35(0.28+0.06) +2.9% 2000.8: git add -A (sparse-v3) 0.06(0.07+0.04) 0.06(0.05+0.06) +0.0% 0.06(0.09+0.01) +0.0% 0.06(0.08+0.03) +0.0% 2000.9: git add -A (sparse-v4) 0.05(0.05+0.04) 0.05(0.05+0.07) +0.0% 0.05(0.04+0.06) +0.0% 0.06(0.06+0.05) +20.0% 2000.10: git add . (full-v3) 0.38(0.31+0.05) 0.37(0.29+0.06) -2.6% 0.37(0.30+0.07) -2.6% 0.37(0.29+0.06) -2.6% 2000.11: git add . (full-v4) 0.35(0.31+0.04) 0.35(0.29+0.07) +0.0% 0.35(0.29+0.05) +0.0% 0.34(0.29+0.06) -2.9% 2000.12: git add . (sparse-v3) 0.06(0.06+0.05) 0.06(0.05+0.06) +0.0% 0.06(0.07+0.05) +0.0% 0.06(0.09+0.03) +0.0% 2000.13: git add . (sparse-v4) 0.06(0.06+0.06) 0.06(0.07+0.04) +0.0% 0.05(0.06+0.05) -16.7% 0.05(0.05+0.07) -16.7% 2000.14: git commit -a -m A (full-v3) 0.48(0.37+0.08) 0.45(0.36+0.08) -6.2% 0.45(0.35+0.09) -6.2% 0.44(0.36+0.07) -8.3% 2000.15: git commit -a -m A (full-v4) 0.45(0.40+0.06) 0.43(0.34+0.07) -4.4% 0.45(0.37+0.06) +0.0% 0.42(0.36+0.05) -6.7% 2000.16: git commit -a -m A (sparse-v3) 0.05(0.05+0.06) 0.05(0.05+0.03) +0.0% 0.05(0.06+0.06) +0.0% 0.05(0.04+0.06) +0.0% 2000.17: git commit -a -m A (sparse-v4) 0.05(0.06+0.03) 0.05(0.06+0.04) +0.0% 0.06(0.07+0.05) +20.0% 0.05(0.04+0.06) +0.0% 2000.18: git checkout -f - (full-v3) 0.55(0.43+0.08) 0.54(0.46+0.05) -1.8% 0.55(0.46+0.07) +0.0% 0.54(0.40+0.10) -1.8% 2000.19: git checkout -f - (full-v4) 0.55(0.41+0.09) 0.50(0.40+0.09) -9.1% 0.51(0.46+0.05) -7.3% 0.51(0.44+0.06) -7.3% 2000.20: git checkout -f - (sparse-v3) 0.06(0.09+0.03) 0.06(0.08+0.03) +0.0% 0.06(0.06+0.05) +0.0% 0.07(0.09+0.03) +16.7% 2000.21: git checkout -f - (sparse-v4) 0.06(0.08+0.04) 0.05(0.07+0.05) -16.7% 0.05(0.07+0.04) -16.7% 0.06(0.09+0.03) +0.0% ``` All of the above were already integrated. ``` 2000.22: git reset (full-v3) 0.41(0.32+0.06) 0.40(0.31+0.06) -2.4% 0.41(0.33+0.05) +0.0% 0.42(0.34+0.04) +2.4% 2000.23: git reset (full-v4) 0.37(0.32+0.05) 0.35(0.30+0.05) -5.4% 0.37(0.30+0.05) +0.0% 0.35(0.31+0.03) -5.4% 2000.24: git reset (sparse-v3) 0.68(0.65+0.05) 0.55(0.52+0.04) -19.1% 0.04(0.05+0.04) -94.1% 0.04(0.05+0.04) -94.1% 2000.25: git reset (sparse-v4) 0.70(0.65+0.05) 0.54(0.50+0.06) -22.9% 0.04(0.07+0.01) -94.3% 0.03(0.05+0.05) -95.7% 2000.26: git reset --hard (full-v3) 0.54(0.43+0.07) 0.53(0.43+0.06) -1.9% 0.55(0.46+0.05) +1.9% 0.55(0.44+0.06) +1.9% 2000.27: git reset --hard (full-v4) 0.50(0.45+0.03) 0.50(0.43+0.05) +0.0% 0.49(0.41+0.06) -2.0% 0.50(0.42+0.05) +0.0% 2000.28: git reset --hard (sparse-v3) 0.83(0.76+0.06) 0.68(0.62+0.05) -18.1% 0.07(0.05+0.02) -91.6% 0.07(0.05+0.02) -91.6% 2000.29: git reset --hard (sparse-v4) 0.80(0.75+0.05) 0.69(0.62+0.06) -13.8% 0.07(0.04+0.02) -91.2% 0.07(0.04+0.03) -91.2% ``` As expected, `git reset [--hard]` improves with the sparse index integration, but remains constant across the full index case. ``` 2000.30: git update-index --add --remove (full-v3) 0.03(0.01+0.01) 0.03(0.02+0.01) +0.0% 0.03(0.02+0.01) +0.0% 0.03(0.01+0.01) +0.0% 2000.31: git update-index --add --remove (full-v4) 0.03(0.02+0.01) 0.03(0.02+0.01) +0.0% 0.03(0.03+0.00) +0.0% 0.03(0.02+0.01) +0.0% 2000.32: git update-index --add --remove (sparse-v3) 0.57(0.54+0.02) 0.43(0.42+0.00) -24.6% 0.44(0.41+0.03) -22.8% 0.44(0.42+0.01) -22.8% 2000.33: git update-index --add --remove (sparse-v4) 0.56(0.52+0.04) 0.43(0.42+0.01) -23.2% 0.44(0.42+0.02) -21.4% 0.42(0.41+0.01) -25.0% ``` These do not change significantly because #423 is not merged. ``` 2000.34: git diff (full-v3) 0.07(0.05+0.03) 0.06(0.05+0.03) -14.3% 0.07(0.05+0.03) +0.0% 0.06(0.05+0.03) -14.3% 2000.35: git diff (full-v4) 0.06(0.05+0.03) 0.06(0.05+0.02) +0.0% 0.06(0.05+0.02) +0.0% 0.06(0.06+0.02) +0.0% 2000.36: git diff (sparse-v3) 0.25(0.23+0.03) 0.17(0.17+0.02) -32.0% 0.18(0.18+0.02) -28.0% 0.01(0.03+0.03) -96.0% 2000.37: git diff (sparse-v4) 0.25(0.22+0.05) 0.16(0.16+0.01) -36.0% 0.18(0.15+0.04) -28.0% 0.01(0.04+0.02) -96.0% 2000.38: git diff --staged (full-v3) 0.03(0.01+0.01) 0.03(0.02+0.01) +0.0% 0.03(0.02+0.01) +0.0% 0.03(0.02+0.00) +0.0% 2000.39: git diff --staged (full-v4) 0.04(0.03+0.01) 0.03(0.02+0.01) -25.0% 0.03(0.03+0.00) -25.0% 0.03(0.03+0.00) -25.0% 2000.40: git diff --staged (sparse-v3) 0.21(0.19+0.01) 0.15(0.13+0.01) -28.6% 0.15(0.14+0.01) -28.6% 0.01(0.01+0.00) -95.2% 2000.41: git diff --staged (sparse-v4) 0.22(0.21+0.01) 0.14(0.11+0.03) -36.4% 0.15(0.13+0.02) -31.8% 0.01(0.01+0.00) -95.5% ``` The `git diff` improvements are measurable. ``` 2000.42: git sparse-checkout reapply (full-v3) 0.63(0.54+0.05) 0.56(0.48+0.04) -11.1% 0.57(0.48+0.03) -9.5% 0.59(0.48+0.05) -6.3% 2000.43: git sparse-checkout reapply (full-v4) 0.60(0.54+0.02) 0.51(0.46+0.03) -15.0% 0.54(0.48+0.02) -10.0% 0.50(0.44+0.04) -16.7% 2000.44: git sparse-checkout reapply (sparse-v3) 0.91(0.86+0.05) 0.05(0.05+0.00) -94.5% 0.06(0.05+0.01) -93.4% 0.06(0.06+0.00) -93.4% 2000.45: git sparse-checkout reapply (sparse-v4) 0.92(0.88+0.04) 0.05(0.05+0.00) -94.6% 0.05(0.05+0.01) -94.6% 0.05(0.04+0.01) -94.6% ``` Finally, the `git sparse-checkout` measurements are also present. This test script is particularly valuable when contributing changes upstream. It can be good to start by adding the lines to the performance test in an early commit, then demonstrating the performance change by copying the necessary lines from the output table into your commit message.

diff: enable and test the sparse index

One thing I forgot when talking about the sparse index is that we have a performance test: `t/perf/p2000-sparse-operations.sh`. This test wasn't helpful for commands like `git merge` that need a particular set of input, but work for more read-only operations. Here is a quick demonstration of how this performance test works so we could have a definitive measure of how your previous updates improved performance. To get these results, I ran the following command in `t/perf`: ``` ./run 4bcd533 f9255a5 f28fc01 b713582 -- p2000-sparse-operations.sh ``` The short-shas correspond to the merge commits for these PRs: * #410 * #421 * #417 * #419 The test takes a copy of the Git repository and creates several copies within a nested directory heirarchy. ``` Test 4bcd533 f9255a5 f28fc01 b713582 ------------------------------------------------------------------------------------------------------------------------------------------------- 2000.2: git status (full-v3) 0.19(0.15+0.05) 0.19(0.16+0.05) +0.0% 0.20(0.18+0.03) +5.3% 0.19(0.17+0.04) +0.0% 2000.3: git status (full-v4) 0.20(0.18+0.04) 0.19(0.15+0.06) -5.0% 0.21(0.18+0.05) +5.0% 0.18(0.18+0.02) -10.0% 2000.4: git status (sparse-v3) 0.04(0.04+0.04) 0.05(0.07+0.04) +25.0% 0.04(0.04+0.05) +0.0% 0.04(0.06+0.04) +0.0% 2000.5: git status (sparse-v4) 0.04(0.03+0.06) 0.04(0.05+0.05) +0.0% 0.05(0.05+0.04) +25.0% 0.05(0.06+0.04) +25.0% 2000.6: git add -A (full-v3) 0.36(0.29+0.05) 0.38(0.28+0.07) +5.6% 0.36(0.31+0.05) +0.0% 0.37(0.31+0.05) +2.8% 2000.7: git add -A (full-v4) 0.34(0.27+0.06) 0.34(0.29+0.05) +0.0% 0.34(0.29+0.04) +0.0% 0.35(0.28+0.06) +2.9% 2000.8: git add -A (sparse-v3) 0.06(0.07+0.04) 0.06(0.05+0.06) +0.0% 0.06(0.09+0.01) +0.0% 0.06(0.08+0.03) +0.0% 2000.9: git add -A (sparse-v4) 0.05(0.05+0.04) 0.05(0.05+0.07) +0.0% 0.05(0.04+0.06) +0.0% 0.06(0.06+0.05) +20.0% 2000.10: git add . (full-v3) 0.38(0.31+0.05) 0.37(0.29+0.06) -2.6% 0.37(0.30+0.07) -2.6% 0.37(0.29+0.06) -2.6% 2000.11: git add . (full-v4) 0.35(0.31+0.04) 0.35(0.29+0.07) +0.0% 0.35(0.29+0.05) +0.0% 0.34(0.29+0.06) -2.9% 2000.12: git add . (sparse-v3) 0.06(0.06+0.05) 0.06(0.05+0.06) +0.0% 0.06(0.07+0.05) +0.0% 0.06(0.09+0.03) +0.0% 2000.13: git add . (sparse-v4) 0.06(0.06+0.06) 0.06(0.07+0.04) +0.0% 0.05(0.06+0.05) -16.7% 0.05(0.05+0.07) -16.7% 2000.14: git commit -a -m A (full-v3) 0.48(0.37+0.08) 0.45(0.36+0.08) -6.2% 0.45(0.35+0.09) -6.2% 0.44(0.36+0.07) -8.3% 2000.15: git commit -a -m A (full-v4) 0.45(0.40+0.06) 0.43(0.34+0.07) -4.4% 0.45(0.37+0.06) +0.0% 0.42(0.36+0.05) -6.7% 2000.16: git commit -a -m A (sparse-v3) 0.05(0.05+0.06) 0.05(0.05+0.03) +0.0% 0.05(0.06+0.06) +0.0% 0.05(0.04+0.06) +0.0% 2000.17: git commit -a -m A (sparse-v4) 0.05(0.06+0.03) 0.05(0.06+0.04) +0.0% 0.06(0.07+0.05) +20.0% 0.05(0.04+0.06) +0.0% 2000.18: git checkout -f - (full-v3) 0.55(0.43+0.08) 0.54(0.46+0.05) -1.8% 0.55(0.46+0.07) +0.0% 0.54(0.40+0.10) -1.8% 2000.19: git checkout -f - (full-v4) 0.55(0.41+0.09) 0.50(0.40+0.09) -9.1% 0.51(0.46+0.05) -7.3% 0.51(0.44+0.06) -7.3% 2000.20: git checkout -f - (sparse-v3) 0.06(0.09+0.03) 0.06(0.08+0.03) +0.0% 0.06(0.06+0.05) +0.0% 0.07(0.09+0.03) +16.7% 2000.21: git checkout -f - (sparse-v4) 0.06(0.08+0.04) 0.05(0.07+0.05) -16.7% 0.05(0.07+0.04) -16.7% 0.06(0.09+0.03) +0.0% ``` All of the above were already integrated. ``` 2000.22: git reset (full-v3) 0.41(0.32+0.06) 0.40(0.31+0.06) -2.4% 0.41(0.33+0.05) +0.0% 0.42(0.34+0.04) +2.4% 2000.23: git reset (full-v4) 0.37(0.32+0.05) 0.35(0.30+0.05) -5.4% 0.37(0.30+0.05) +0.0% 0.35(0.31+0.03) -5.4% 2000.24: git reset (sparse-v3) 0.68(0.65+0.05) 0.55(0.52+0.04) -19.1% 0.04(0.05+0.04) -94.1% 0.04(0.05+0.04) -94.1% 2000.25: git reset (sparse-v4) 0.70(0.65+0.05) 0.54(0.50+0.06) -22.9% 0.04(0.07+0.01) -94.3% 0.03(0.05+0.05) -95.7% 2000.26: git reset --hard (full-v3) 0.54(0.43+0.07) 0.53(0.43+0.06) -1.9% 0.55(0.46+0.05) +1.9% 0.55(0.44+0.06) +1.9% 2000.27: git reset --hard (full-v4) 0.50(0.45+0.03) 0.50(0.43+0.05) +0.0% 0.49(0.41+0.06) -2.0% 0.50(0.42+0.05) +0.0% 2000.28: git reset --hard (sparse-v3) 0.83(0.76+0.06) 0.68(0.62+0.05) -18.1% 0.07(0.05+0.02) -91.6% 0.07(0.05+0.02) -91.6% 2000.29: git reset --hard (sparse-v4) 0.80(0.75+0.05) 0.69(0.62+0.06) -13.8% 0.07(0.04+0.02) -91.2% 0.07(0.04+0.03) -91.2% ``` As expected, `git reset [--hard]` improves with the sparse index integration, but remains constant across the full index case. ``` 2000.30: git update-index --add --remove (full-v3) 0.03(0.01+0.01) 0.03(0.02+0.01) +0.0% 0.03(0.02+0.01) +0.0% 0.03(0.01+0.01) +0.0% 2000.31: git update-index --add --remove (full-v4) 0.03(0.02+0.01) 0.03(0.02+0.01) +0.0% 0.03(0.03+0.00) +0.0% 0.03(0.02+0.01) +0.0% 2000.32: git update-index --add --remove (sparse-v3) 0.57(0.54+0.02) 0.43(0.42+0.00) -24.6% 0.44(0.41+0.03) -22.8% 0.44(0.42+0.01) -22.8% 2000.33: git update-index --add --remove (sparse-v4) 0.56(0.52+0.04) 0.43(0.42+0.01) -23.2% 0.44(0.42+0.02) -21.4% 0.42(0.41+0.01) -25.0% ``` These do not change significantly because #423 is not merged. ``` 2000.34: git diff (full-v3) 0.07(0.05+0.03) 0.06(0.05+0.03) -14.3% 0.07(0.05+0.03) +0.0% 0.06(0.05+0.03) -14.3% 2000.35: git diff (full-v4) 0.06(0.05+0.03) 0.06(0.05+0.02) +0.0% 0.06(0.05+0.02) +0.0% 0.06(0.06+0.02) +0.0% 2000.36: git diff (sparse-v3) 0.25(0.23+0.03) 0.17(0.17+0.02) -32.0% 0.18(0.18+0.02) -28.0% 0.01(0.03+0.03) -96.0% 2000.37: git diff (sparse-v4) 0.25(0.22+0.05) 0.16(0.16+0.01) -36.0% 0.18(0.15+0.04) -28.0% 0.01(0.04+0.02) -96.0% 2000.38: git diff --staged (full-v3) 0.03(0.01+0.01) 0.03(0.02+0.01) +0.0% 0.03(0.02+0.01) +0.0% 0.03(0.02+0.00) +0.0% 2000.39: git diff --staged (full-v4) 0.04(0.03+0.01) 0.03(0.02+0.01) -25.0% 0.03(0.03+0.00) -25.0% 0.03(0.03+0.00) -25.0% 2000.40: git diff --staged (sparse-v3) 0.21(0.19+0.01) 0.15(0.13+0.01) -28.6% 0.15(0.14+0.01) -28.6% 0.01(0.01+0.00) -95.2% 2000.41: git diff --staged (sparse-v4) 0.22(0.21+0.01) 0.14(0.11+0.03) -36.4% 0.15(0.13+0.02) -31.8% 0.01(0.01+0.00) -95.5% ``` The `git diff` improvements are measurable. ``` 2000.42: git sparse-checkout reapply (full-v3) 0.63(0.54+0.05) 0.56(0.48+0.04) -11.1% 0.57(0.48+0.03) -9.5% 0.59(0.48+0.05) -6.3% 2000.43: git sparse-checkout reapply (full-v4) 0.60(0.54+0.02) 0.51(0.46+0.03) -15.0% 0.54(0.48+0.02) -10.0% 0.50(0.44+0.04) -16.7% 2000.44: git sparse-checkout reapply (sparse-v3) 0.91(0.86+0.05) 0.05(0.05+0.00) -94.5% 0.06(0.05+0.01) -93.4% 0.06(0.06+0.00) -93.4% 2000.45: git sparse-checkout reapply (sparse-v4) 0.92(0.88+0.04) 0.05(0.05+0.00) -94.6% 0.05(0.05+0.01) -94.6% 0.05(0.04+0.01) -94.6% ``` Finally, the `git sparse-checkout` measurements are also present. This test script is particularly valuable when contributing changes upstream. It can be good to start by adding the lines to the performance test in an early commit, then demonstrating the performance change by copying the necessary lines from the output table into your commit message.

diff: enable and test the sparse index

One thing I forgot when talking about the sparse index is that we have a performance test: `t/perf/p2000-sparse-operations.sh`. This test wasn't helpful for commands like `git merge` that need a particular set of input, but work for more read-only operations. Here is a quick demonstration of how this performance test works so we could have a definitive measure of how your previous updates improved performance. To get these results, I ran the following command in `t/perf`: ``` ./run 4bcd533 f9255a5 f28fc01 b713582 -- p2000-sparse-operations.sh ``` The short-shas correspond to the merge commits for these PRs: * #410 * #421 * #417 * #419 The test takes a copy of the Git repository and creates several copies within a nested directory heirarchy. ``` Test 4bcd533 f9255a5 f28fc01 b713582 ------------------------------------------------------------------------------------------------------------------------------------------------- 2000.2: git status (full-v3) 0.19(0.15+0.05) 0.19(0.16+0.05) +0.0% 0.20(0.18+0.03) +5.3% 0.19(0.17+0.04) +0.0% 2000.3: git status (full-v4) 0.20(0.18+0.04) 0.19(0.15+0.06) -5.0% 0.21(0.18+0.05) +5.0% 0.18(0.18+0.02) -10.0% 2000.4: git status (sparse-v3) 0.04(0.04+0.04) 0.05(0.07+0.04) +25.0% 0.04(0.04+0.05) +0.0% 0.04(0.06+0.04) +0.0% 2000.5: git status (sparse-v4) 0.04(0.03+0.06) 0.04(0.05+0.05) +0.0% 0.05(0.05+0.04) +25.0% 0.05(0.06+0.04) +25.0% 2000.6: git add -A (full-v3) 0.36(0.29+0.05) 0.38(0.28+0.07) +5.6% 0.36(0.31+0.05) +0.0% 0.37(0.31+0.05) +2.8% 2000.7: git add -A (full-v4) 0.34(0.27+0.06) 0.34(0.29+0.05) +0.0% 0.34(0.29+0.04) +0.0% 0.35(0.28+0.06) +2.9% 2000.8: git add -A (sparse-v3) 0.06(0.07+0.04) 0.06(0.05+0.06) +0.0% 0.06(0.09+0.01) +0.0% 0.06(0.08+0.03) +0.0% 2000.9: git add -A (sparse-v4) 0.05(0.05+0.04) 0.05(0.05+0.07) +0.0% 0.05(0.04+0.06) +0.0% 0.06(0.06+0.05) +20.0% 2000.10: git add . (full-v3) 0.38(0.31+0.05) 0.37(0.29+0.06) -2.6% 0.37(0.30+0.07) -2.6% 0.37(0.29+0.06) -2.6% 2000.11: git add . (full-v4) 0.35(0.31+0.04) 0.35(0.29+0.07) +0.0% 0.35(0.29+0.05) +0.0% 0.34(0.29+0.06) -2.9% 2000.12: git add . (sparse-v3) 0.06(0.06+0.05) 0.06(0.05+0.06) +0.0% 0.06(0.07+0.05) +0.0% 0.06(0.09+0.03) +0.0% 2000.13: git add . (sparse-v4) 0.06(0.06+0.06) 0.06(0.07+0.04) +0.0% 0.05(0.06+0.05) -16.7% 0.05(0.05+0.07) -16.7% 2000.14: git commit -a -m A (full-v3) 0.48(0.37+0.08) 0.45(0.36+0.08) -6.2% 0.45(0.35+0.09) -6.2% 0.44(0.36+0.07) -8.3% 2000.15: git commit -a -m A (full-v4) 0.45(0.40+0.06) 0.43(0.34+0.07) -4.4% 0.45(0.37+0.06) +0.0% 0.42(0.36+0.05) -6.7% 2000.16: git commit -a -m A (sparse-v3) 0.05(0.05+0.06) 0.05(0.05+0.03) +0.0% 0.05(0.06+0.06) +0.0% 0.05(0.04+0.06) +0.0% 2000.17: git commit -a -m A (sparse-v4) 0.05(0.06+0.03) 0.05(0.06+0.04) +0.0% 0.06(0.07+0.05) +20.0% 0.05(0.04+0.06) +0.0% 2000.18: git checkout -f - (full-v3) 0.55(0.43+0.08) 0.54(0.46+0.05) -1.8% 0.55(0.46+0.07) +0.0% 0.54(0.40+0.10) -1.8% 2000.19: git checkout -f - (full-v4) 0.55(0.41+0.09) 0.50(0.40+0.09) -9.1% 0.51(0.46+0.05) -7.3% 0.51(0.44+0.06) -7.3% 2000.20: git checkout -f - (sparse-v3) 0.06(0.09+0.03) 0.06(0.08+0.03) +0.0% 0.06(0.06+0.05) +0.0% 0.07(0.09+0.03) +16.7% 2000.21: git checkout -f - (sparse-v4) 0.06(0.08+0.04) 0.05(0.07+0.05) -16.7% 0.05(0.07+0.04) -16.7% 0.06(0.09+0.03) +0.0% ``` All of the above were already integrated. ``` 2000.22: git reset (full-v3) 0.41(0.32+0.06) 0.40(0.31+0.06) -2.4% 0.41(0.33+0.05) +0.0% 0.42(0.34+0.04) +2.4% 2000.23: git reset (full-v4) 0.37(0.32+0.05) 0.35(0.30+0.05) -5.4% 0.37(0.30+0.05) +0.0% 0.35(0.31+0.03) -5.4% 2000.24: git reset (sparse-v3) 0.68(0.65+0.05) 0.55(0.52+0.04) -19.1% 0.04(0.05+0.04) -94.1% 0.04(0.05+0.04) -94.1% 2000.25: git reset (sparse-v4) 0.70(0.65+0.05) 0.54(0.50+0.06) -22.9% 0.04(0.07+0.01) -94.3% 0.03(0.05+0.05) -95.7% 2000.26: git reset --hard (full-v3) 0.54(0.43+0.07) 0.53(0.43+0.06) -1.9% 0.55(0.46+0.05) +1.9% 0.55(0.44+0.06) +1.9% 2000.27: git reset --hard (full-v4) 0.50(0.45+0.03) 0.50(0.43+0.05) +0.0% 0.49(0.41+0.06) -2.0% 0.50(0.42+0.05) +0.0% 2000.28: git reset --hard (sparse-v3) 0.83(0.76+0.06) 0.68(0.62+0.05) -18.1% 0.07(0.05+0.02) -91.6% 0.07(0.05+0.02) -91.6% 2000.29: git reset --hard (sparse-v4) 0.80(0.75+0.05) 0.69(0.62+0.06) -13.8% 0.07(0.04+0.02) -91.2% 0.07(0.04+0.03) -91.2% ``` As expected, `git reset [--hard]` improves with the sparse index integration, but remains constant across the full index case. ``` 2000.30: git update-index --add --remove (full-v3) 0.03(0.01+0.01) 0.03(0.02+0.01) +0.0% 0.03(0.02+0.01) +0.0% 0.03(0.01+0.01) +0.0% 2000.31: git update-index --add --remove (full-v4) 0.03(0.02+0.01) 0.03(0.02+0.01) +0.0% 0.03(0.03+0.00) +0.0% 0.03(0.02+0.01) +0.0% 2000.32: git update-index --add --remove (sparse-v3) 0.57(0.54+0.02) 0.43(0.42+0.00) -24.6% 0.44(0.41+0.03) -22.8% 0.44(0.42+0.01) -22.8% 2000.33: git update-index --add --remove (sparse-v4) 0.56(0.52+0.04) 0.43(0.42+0.01) -23.2% 0.44(0.42+0.02) -21.4% 0.42(0.41+0.01) -25.0% ``` These do not change significantly because #423 is not merged. ``` 2000.34: git diff (full-v3) 0.07(0.05+0.03) 0.06(0.05+0.03) -14.3% 0.07(0.05+0.03) +0.0% 0.06(0.05+0.03) -14.3% 2000.35: git diff (full-v4) 0.06(0.05+0.03) 0.06(0.05+0.02) +0.0% 0.06(0.05+0.02) +0.0% 0.06(0.06+0.02) +0.0% 2000.36: git diff (sparse-v3) 0.25(0.23+0.03) 0.17(0.17+0.02) -32.0% 0.18(0.18+0.02) -28.0% 0.01(0.03+0.03) -96.0% 2000.37: git diff (sparse-v4) 0.25(0.22+0.05) 0.16(0.16+0.01) -36.0% 0.18(0.15+0.04) -28.0% 0.01(0.04+0.02) -96.0% 2000.38: git diff --staged (full-v3) 0.03(0.01+0.01) 0.03(0.02+0.01) +0.0% 0.03(0.02+0.01) +0.0% 0.03(0.02+0.00) +0.0% 2000.39: git diff --staged (full-v4) 0.04(0.03+0.01) 0.03(0.02+0.01) -25.0% 0.03(0.03+0.00) -25.0% 0.03(0.03+0.00) -25.0% 2000.40: git diff --staged (sparse-v3) 0.21(0.19+0.01) 0.15(0.13+0.01) -28.6% 0.15(0.14+0.01) -28.6% 0.01(0.01+0.00) -95.2% 2000.41: git diff --staged (sparse-v4) 0.22(0.21+0.01) 0.14(0.11+0.03) -36.4% 0.15(0.13+0.02) -31.8% 0.01(0.01+0.00) -95.5% ``` The `git diff` improvements are measurable. ``` 2000.42: git sparse-checkout reapply (full-v3) 0.63(0.54+0.05) 0.56(0.48+0.04) -11.1% 0.57(0.48+0.03) -9.5% 0.59(0.48+0.05) -6.3% 2000.43: git sparse-checkout reapply (full-v4) 0.60(0.54+0.02) 0.51(0.46+0.03) -15.0% 0.54(0.48+0.02) -10.0% 0.50(0.44+0.04) -16.7% 2000.44: git sparse-checkout reapply (sparse-v3) 0.91(0.86+0.05) 0.05(0.05+0.00) -94.5% 0.06(0.05+0.01) -93.4% 0.06(0.06+0.00) -93.4% 2000.45: git sparse-checkout reapply (sparse-v4) 0.92(0.88+0.04) 0.05(0.05+0.00) -94.6% 0.05(0.05+0.01) -94.6% 0.05(0.04+0.01) -94.6% ``` Finally, the `git sparse-checkout` measurements are also present. This test script is particularly valuable when contributing changes upstream. It can be good to start by adding the lines to the performance test in an early commit, then demonstrating the performance change by copying the necessary lines from the output table into your commit message.

diff: enable and test the sparse index

One thing I forgot when talking about the sparse index is that we have a performance test: `t/perf/p2000-sparse-operations.sh`. This test wasn't helpful for commands like `git merge` that need a particular set of input, but work for more read-only operations. Here is a quick demonstration of how this performance test works so we could have a definitive measure of how your previous updates improved performance. To get these results, I ran the following command in `t/perf`: ``` ./run 4bcd533 f9255a5 f28fc01 b713582 -- p2000-sparse-operations.sh ``` The short-shas correspond to the merge commits for these PRs: * #410 * #421 * #417 * #419 The test takes a copy of the Git repository and creates several copies within a nested directory heirarchy. ``` Test 4bcd533 f9255a5 f28fc01 b713582 ------------------------------------------------------------------------------------------------------------------------------------------------- 2000.2: git status (full-v3) 0.19(0.15+0.05) 0.19(0.16+0.05) +0.0% 0.20(0.18+0.03) +5.3% 0.19(0.17+0.04) +0.0% 2000.3: git status (full-v4) 0.20(0.18+0.04) 0.19(0.15+0.06) -5.0% 0.21(0.18+0.05) +5.0% 0.18(0.18+0.02) -10.0% 2000.4: git status (sparse-v3) 0.04(0.04+0.04) 0.05(0.07+0.04) +25.0% 0.04(0.04+0.05) +0.0% 0.04(0.06+0.04) +0.0% 2000.5: git status (sparse-v4) 0.04(0.03+0.06) 0.04(0.05+0.05) +0.0% 0.05(0.05+0.04) +25.0% 0.05(0.06+0.04) +25.0% 2000.6: git add -A (full-v3) 0.36(0.29+0.05) 0.38(0.28+0.07) +5.6% 0.36(0.31+0.05) +0.0% 0.37(0.31+0.05) +2.8% 2000.7: git add -A (full-v4) 0.34(0.27+0.06) 0.34(0.29+0.05) +0.0% 0.34(0.29+0.04) +0.0% 0.35(0.28+0.06) +2.9% 2000.8: git add -A (sparse-v3) 0.06(0.07+0.04) 0.06(0.05+0.06) +0.0% 0.06(0.09+0.01) +0.0% 0.06(0.08+0.03) +0.0% 2000.9: git add -A (sparse-v4) 0.05(0.05+0.04) 0.05(0.05+0.07) +0.0% 0.05(0.04+0.06) +0.0% 0.06(0.06+0.05) +20.0% 2000.10: git add . (full-v3) 0.38(0.31+0.05) 0.37(0.29+0.06) -2.6% 0.37(0.30+0.07) -2.6% 0.37(0.29+0.06) -2.6% 2000.11: git add . (full-v4) 0.35(0.31+0.04) 0.35(0.29+0.07) +0.0% 0.35(0.29+0.05) +0.0% 0.34(0.29+0.06) -2.9% 2000.12: git add . (sparse-v3) 0.06(0.06+0.05) 0.06(0.05+0.06) +0.0% 0.06(0.07+0.05) +0.0% 0.06(0.09+0.03) +0.0% 2000.13: git add . (sparse-v4) 0.06(0.06+0.06) 0.06(0.07+0.04) +0.0% 0.05(0.06+0.05) -16.7% 0.05(0.05+0.07) -16.7% 2000.14: git commit -a -m A (full-v3) 0.48(0.37+0.08) 0.45(0.36+0.08) -6.2% 0.45(0.35+0.09) -6.2% 0.44(0.36+0.07) -8.3% 2000.15: git commit -a -m A (full-v4) 0.45(0.40+0.06) 0.43(0.34+0.07) -4.4% 0.45(0.37+0.06) +0.0% 0.42(0.36+0.05) -6.7% 2000.16: git commit -a -m A (sparse-v3) 0.05(0.05+0.06) 0.05(0.05+0.03) +0.0% 0.05(0.06+0.06) +0.0% 0.05(0.04+0.06) +0.0% 2000.17: git commit -a -m A (sparse-v4) 0.05(0.06+0.03) 0.05(0.06+0.04) +0.0% 0.06(0.07+0.05) +20.0% 0.05(0.04+0.06) +0.0% 2000.18: git checkout -f - (full-v3) 0.55(0.43+0.08) 0.54(0.46+0.05) -1.8% 0.55(0.46+0.07) +0.0% 0.54(0.40+0.10) -1.8% 2000.19: git checkout -f - (full-v4) 0.55(0.41+0.09) 0.50(0.40+0.09) -9.1% 0.51(0.46+0.05) -7.3% 0.51(0.44+0.06) -7.3% 2000.20: git checkout -f - (sparse-v3) 0.06(0.09+0.03) 0.06(0.08+0.03) +0.0% 0.06(0.06+0.05) +0.0% 0.07(0.09+0.03) +16.7% 2000.21: git checkout -f - (sparse-v4) 0.06(0.08+0.04) 0.05(0.07+0.05) -16.7% 0.05(0.07+0.04) -16.7% 0.06(0.09+0.03) +0.0% ``` All of the above were already integrated. ``` 2000.22: git reset (full-v3) 0.41(0.32+0.06) 0.40(0.31+0.06) -2.4% 0.41(0.33+0.05) +0.0% 0.42(0.34+0.04) +2.4% 2000.23: git reset (full-v4) 0.37(0.32+0.05) 0.35(0.30+0.05) -5.4% 0.37(0.30+0.05) +0.0% 0.35(0.31+0.03) -5.4% 2000.24: git reset (sparse-v3) 0.68(0.65+0.05) 0.55(0.52+0.04) -19.1% 0.04(0.05+0.04) -94.1% 0.04(0.05+0.04) -94.1% 2000.25: git reset (sparse-v4) 0.70(0.65+0.05) 0.54(0.50+0.06) -22.9% 0.04(0.07+0.01) -94.3% 0.03(0.05+0.05) -95.7% 2000.26: git reset --hard (full-v3) 0.54(0.43+0.07) 0.53(0.43+0.06) -1.9% 0.55(0.46+0.05) +1.9% 0.55(0.44+0.06) +1.9% 2000.27: git reset --hard (full-v4) 0.50(0.45+0.03) 0.50(0.43+0.05) +0.0% 0.49(0.41+0.06) -2.0% 0.50(0.42+0.05) +0.0% 2000.28: git reset --hard (sparse-v3) 0.83(0.76+0.06) 0.68(0.62+0.05) -18.1% 0.07(0.05+0.02) -91.6% 0.07(0.05+0.02) -91.6% 2000.29: git reset --hard (sparse-v4) 0.80(0.75+0.05) 0.69(0.62+0.06) -13.8% 0.07(0.04+0.02) -91.2% 0.07(0.04+0.03) -91.2% ``` As expected, `git reset [--hard]` improves with the sparse index integration, but remains constant across the full index case. ``` 2000.30: git update-index --add --remove (full-v3) 0.03(0.01+0.01) 0.03(0.02+0.01) +0.0% 0.03(0.02+0.01) +0.0% 0.03(0.01+0.01) +0.0% 2000.31: git update-index --add --remove (full-v4) 0.03(0.02+0.01) 0.03(0.02+0.01) +0.0% 0.03(0.03+0.00) +0.0% 0.03(0.02+0.01) +0.0% 2000.32: git update-index --add --remove (sparse-v3) 0.57(0.54+0.02) 0.43(0.42+0.00) -24.6% 0.44(0.41+0.03) -22.8% 0.44(0.42+0.01) -22.8% 2000.33: git update-index --add --remove (sparse-v4) 0.56(0.52+0.04) 0.43(0.42+0.01) -23.2% 0.44(0.42+0.02) -21.4% 0.42(0.41+0.01) -25.0% ``` These do not change significantly because #423 is not merged. ``` 2000.34: git diff (full-v3) 0.07(0.05+0.03) 0.06(0.05+0.03) -14.3% 0.07(0.05+0.03) +0.0% 0.06(0.05+0.03) -14.3% 2000.35: git diff (full-v4) 0.06(0.05+0.03) 0.06(0.05+0.02) +0.0% 0.06(0.05+0.02) +0.0% 0.06(0.06+0.02) +0.0% 2000.36: git diff (sparse-v3) 0.25(0.23+0.03) 0.17(0.17+0.02) -32.0% 0.18(0.18+0.02) -28.0% 0.01(0.03+0.03) -96.0% 2000.37: git diff (sparse-v4) 0.25(0.22+0.05) 0.16(0.16+0.01) -36.0% 0.18(0.15+0.04) -28.0% 0.01(0.04+0.02) -96.0% 2000.38: git diff --staged (full-v3) 0.03(0.01+0.01) 0.03(0.02+0.01) +0.0% 0.03(0.02+0.01) +0.0% 0.03(0.02+0.00) +0.0% 2000.39: git diff --staged (full-v4) 0.04(0.03+0.01) 0.03(0.02+0.01) -25.0% 0.03(0.03+0.00) -25.0% 0.03(0.03+0.00) -25.0% 2000.40: git diff --staged (sparse-v3) 0.21(0.19+0.01) 0.15(0.13+0.01) -28.6% 0.15(0.14+0.01) -28.6% 0.01(0.01+0.00) -95.2% 2000.41: git diff --staged (sparse-v4) 0.22(0.21+0.01) 0.14(0.11+0.03) -36.4% 0.15(0.13+0.02) -31.8% 0.01(0.01+0.00) -95.5% ``` The `git diff` improvements are measurable. ``` 2000.42: git sparse-checkout reapply (full-v3) 0.63(0.54+0.05) 0.56(0.48+0.04) -11.1% 0.57(0.48+0.03) -9.5% 0.59(0.48+0.05) -6.3% 2000.43: git sparse-checkout reapply (full-v4) 0.60(0.54+0.02) 0.51(0.46+0.03) -15.0% 0.54(0.48+0.02) -10.0% 0.50(0.44+0.04) -16.7% 2000.44: git sparse-checkout reapply (sparse-v3) 0.91(0.86+0.05) 0.05(0.05+0.00) -94.5% 0.06(0.05+0.01) -93.4% 0.06(0.06+0.00) -93.4% 2000.45: git sparse-checkout reapply (sparse-v4) 0.92(0.88+0.04) 0.05(0.05+0.00) -94.6% 0.05(0.05+0.01) -94.6% 0.05(0.04+0.01) -94.6% ``` Finally, the `git sparse-checkout` measurements are also present. This test script is particularly valuable when contributing changes upstream. It can be good to start by adding the lines to the performance test in an early commit, then demonstrating the performance change by copying the necessary lines from the output table into your commit message.

diff: enable and test the sparse index

One thing I forgot when talking about the sparse index is that we have a performance test: `t/perf/p2000-sparse-operations.sh`. This test wasn't helpful for commands like `git merge` that need a particular set of input, but work for more read-only operations. Here is a quick demonstration of how this performance test works so we could have a definitive measure of how your previous updates improved performance. To get these results, I ran the following command in `t/perf`: ``` ./run 4bcd533 f9255a5 f28fc01 b713582 -- p2000-sparse-operations.sh ``` The short-shas correspond to the merge commits for these PRs: * #410 * #421 * #417 * #419 The test takes a copy of the Git repository and creates several copies within a nested directory heirarchy. ``` Test 4bcd533 f9255a5 f28fc01 b713582 ------------------------------------------------------------------------------------------------------------------------------------------------- 2000.2: git status (full-v3) 0.19(0.15+0.05) 0.19(0.16+0.05) +0.0% 0.20(0.18+0.03) +5.3% 0.19(0.17+0.04) +0.0% 2000.3: git status (full-v4) 0.20(0.18+0.04) 0.19(0.15+0.06) -5.0% 0.21(0.18+0.05) +5.0% 0.18(0.18+0.02) -10.0% 2000.4: git status (sparse-v3) 0.04(0.04+0.04) 0.05(0.07+0.04) +25.0% 0.04(0.04+0.05) +0.0% 0.04(0.06+0.04) +0.0% 2000.5: git status (sparse-v4) 0.04(0.03+0.06) 0.04(0.05+0.05) +0.0% 0.05(0.05+0.04) +25.0% 0.05(0.06+0.04) +25.0% 2000.6: git add -A (full-v3) 0.36(0.29+0.05) 0.38(0.28+0.07) +5.6% 0.36(0.31+0.05) +0.0% 0.37(0.31+0.05) +2.8% 2000.7: git add -A (full-v4) 0.34(0.27+0.06) 0.34(0.29+0.05) +0.0% 0.34(0.29+0.04) +0.0% 0.35(0.28+0.06) +2.9% 2000.8: git add -A (sparse-v3) 0.06(0.07+0.04) 0.06(0.05+0.06) +0.0% 0.06(0.09+0.01) +0.0% 0.06(0.08+0.03) +0.0% 2000.9: git add -A (sparse-v4) 0.05(0.05+0.04) 0.05(0.05+0.07) +0.0% 0.05(0.04+0.06) +0.0% 0.06(0.06+0.05) +20.0% 2000.10: git add . (full-v3) 0.38(0.31+0.05) 0.37(0.29+0.06) -2.6% 0.37(0.30+0.07) -2.6% 0.37(0.29+0.06) -2.6% 2000.11: git add . (full-v4) 0.35(0.31+0.04) 0.35(0.29+0.07) +0.0% 0.35(0.29+0.05) +0.0% 0.34(0.29+0.06) -2.9% 2000.12: git add . (sparse-v3) 0.06(0.06+0.05) 0.06(0.05+0.06) +0.0% 0.06(0.07+0.05) +0.0% 0.06(0.09+0.03) +0.0% 2000.13: git add . (sparse-v4) 0.06(0.06+0.06) 0.06(0.07+0.04) +0.0% 0.05(0.06+0.05) -16.7% 0.05(0.05+0.07) -16.7% 2000.14: git commit -a -m A (full-v3) 0.48(0.37+0.08) 0.45(0.36+0.08) -6.2% 0.45(0.35+0.09) -6.2% 0.44(0.36+0.07) -8.3% 2000.15: git commit -a -m A (full-v4) 0.45(0.40+0.06) 0.43(0.34+0.07) -4.4% 0.45(0.37+0.06) +0.0% 0.42(0.36+0.05) -6.7% 2000.16: git commit -a -m A (sparse-v3) 0.05(0.05+0.06) 0.05(0.05+0.03) +0.0% 0.05(0.06+0.06) +0.0% 0.05(0.04+0.06) +0.0% 2000.17: git commit -a -m A (sparse-v4) 0.05(0.06+0.03) 0.05(0.06+0.04) +0.0% 0.06(0.07+0.05) +20.0% 0.05(0.04+0.06) +0.0% 2000.18: git checkout -f - (full-v3) 0.55(0.43+0.08) 0.54(0.46+0.05) -1.8% 0.55(0.46+0.07) +0.0% 0.54(0.40+0.10) -1.8% 2000.19: git checkout -f - (full-v4) 0.55(0.41+0.09) 0.50(0.40+0.09) -9.1% 0.51(0.46+0.05) -7.3% 0.51(0.44+0.06) -7.3% 2000.20: git checkout -f - (sparse-v3) 0.06(0.09+0.03) 0.06(0.08+0.03) +0.0% 0.06(0.06+0.05) +0.0% 0.07(0.09+0.03) +16.7% 2000.21: git checkout -f - (sparse-v4) 0.06(0.08+0.04) 0.05(0.07+0.05) -16.7% 0.05(0.07+0.04) -16.7% 0.06(0.09+0.03) +0.0% ``` All of the above were already integrated. ``` 2000.22: git reset (full-v3) 0.41(0.32+0.06) 0.40(0.31+0.06) -2.4% 0.41(0.33+0.05) +0.0% 0.42(0.34+0.04) +2.4% 2000.23: git reset (full-v4) 0.37(0.32+0.05) 0.35(0.30+0.05) -5.4% 0.37(0.30+0.05) +0.0% 0.35(0.31+0.03) -5.4% 2000.24: git reset (sparse-v3) 0.68(0.65+0.05) 0.55(0.52+0.04) -19.1% 0.04(0.05+0.04) -94.1% 0.04(0.05+0.04) -94.1% 2000.25: git reset (sparse-v4) 0.70(0.65+0.05) 0.54(0.50+0.06) -22.9% 0.04(0.07+0.01) -94.3% 0.03(0.05+0.05) -95.7% 2000.26: git reset --hard (full-v3) 0.54(0.43+0.07) 0.53(0.43+0.06) -1.9% 0.55(0.46+0.05) +1.9% 0.55(0.44+0.06) +1.9% 2000.27: git reset --hard (full-v4) 0.50(0.45+0.03) 0.50(0.43+0.05) +0.0% 0.49(0.41+0.06) -2.0% 0.50(0.42+0.05) +0.0% 2000.28: git reset --hard (sparse-v3) 0.83(0.76+0.06) 0.68(0.62+0.05) -18.1% 0.07(0.05+0.02) -91.6% 0.07(0.05+0.02) -91.6% 2000.29: git reset --hard (sparse-v4) 0.80(0.75+0.05) 0.69(0.62+0.06) -13.8% 0.07(0.04+0.02) -91.2% 0.07(0.04+0.03) -91.2% ``` As expected, `git reset [--hard]` improves with the sparse index integration, but remains constant across the full index case. ``` 2000.30: git update-index --add --remove (full-v3) 0.03(0.01+0.01) 0.03(0.02+0.01) +0.0% 0.03(0.02+0.01) +0.0% 0.03(0.01+0.01) +0.0% 2000.31: git update-index --add --remove (full-v4) 0.03(0.02+0.01) 0.03(0.02+0.01) +0.0% 0.03(0.03+0.00) +0.0% 0.03(0.02+0.01) +0.0% 2000.32: git update-index --add --remove (sparse-v3) 0.57(0.54+0.02) 0.43(0.42+0.00) -24.6% 0.44(0.41+0.03) -22.8% 0.44(0.42+0.01) -22.8% 2000.33: git update-index --add --remove (sparse-v4) 0.56(0.52+0.04) 0.43(0.42+0.01) -23.2% 0.44(0.42+0.02) -21.4% 0.42(0.41+0.01) -25.0% ``` These do not change significantly because #423 is not merged. ``` 2000.34: git diff (full-v3) 0.07(0.05+0.03) 0.06(0.05+0.03) -14.3% 0.07(0.05+0.03) +0.0% 0.06(0.05+0.03) -14.3% 2000.35: git diff (full-v4) 0.06(0.05+0.03) 0.06(0.05+0.02) +0.0% 0.06(0.05+0.02) +0.0% 0.06(0.06+0.02) +0.0% 2000.36: git diff (sparse-v3) 0.25(0.23+0.03) 0.17(0.17+0.02) -32.0% 0.18(0.18+0.02) -28.0% 0.01(0.03+0.03) -96.0% 2000.37: git diff (sparse-v4) 0.25(0.22+0.05) 0.16(0.16+0.01) -36.0% 0.18(0.15+0.04) -28.0% 0.01(0.04+0.02) -96.0% 2000.38: git diff --staged (full-v3) 0.03(0.01+0.01) 0.03(0.02+0.01) +0.0% 0.03(0.02+0.01) +0.0% 0.03(0.02+0.00) +0.0% 2000.39: git diff --staged (full-v4) 0.04(0.03+0.01) 0.03(0.02+0.01) -25.0% 0.03(0.03+0.00) -25.0% 0.03(0.03+0.00) -25.0% 2000.40: git diff --staged (sparse-v3) 0.21(0.19+0.01) 0.15(0.13+0.01) -28.6% 0.15(0.14+0.01) -28.6% 0.01(0.01+0.00) -95.2% 2000.41: git diff --staged (sparse-v4) 0.22(0.21+0.01) 0.14(0.11+0.03) -36.4% 0.15(0.13+0.02) -31.8% 0.01(0.01+0.00) -95.5% ``` The `git diff` improvements are measurable. ``` 2000.42: git sparse-checkout reapply (full-v3) 0.63(0.54+0.05) 0.56(0.48+0.04) -11.1% 0.57(0.48+0.03) -9.5% 0.59(0.48+0.05) -6.3% 2000.43: git sparse-checkout reapply (full-v4) 0.60(0.54+0.02) 0.51(0.46+0.03) -15.0% 0.54(0.48+0.02) -10.0% 0.50(0.44+0.04) -16.7% 2000.44: git sparse-checkout reapply (sparse-v3) 0.91(0.86+0.05) 0.05(0.05+0.00) -94.5% 0.06(0.05+0.01) -93.4% 0.06(0.06+0.00) -93.4% 2000.45: git sparse-checkout reapply (sparse-v4) 0.92(0.88+0.04) 0.05(0.05+0.00) -94.6% 0.05(0.05+0.01) -94.6% 0.05(0.04+0.01) -94.6% ``` Finally, the `git sparse-checkout` measurements are also present. This test script is particularly valuable when contributing changes upstream. It can be good to start by adding the lines to the performance test in an early commit, then demonstrating the performance change by copying the necessary lines from the output table into your commit message.

diff: enable and test the sparse index

One thing I forgot when talking about the sparse index is that we have a performance test: `t/perf/p2000-sparse-operations.sh`. This test wasn't helpful for commands like `git merge` that need a particular set of input, but work for more read-only operations. Here is a quick demonstration of how this performance test works so we could have a definitive measure of how your previous updates improved performance. To get these results, I ran the following command in `t/perf`: ``` ./run 4bcd533 f9255a5 f28fc01 b713582 -- p2000-sparse-operations.sh ``` The short-shas correspond to the merge commits for these PRs: * #410 * #421 * #417 * #419 The test takes a copy of the Git repository and creates several copies within a nested directory heirarchy. ``` Test 4bcd533 f9255a5 f28fc01 b713582 ------------------------------------------------------------------------------------------------------------------------------------------------- 2000.2: git status (full-v3) 0.19(0.15+0.05) 0.19(0.16+0.05) +0.0% 0.20(0.18+0.03) +5.3% 0.19(0.17+0.04) +0.0% 2000.3: git status (full-v4) 0.20(0.18+0.04) 0.19(0.15+0.06) -5.0% 0.21(0.18+0.05) +5.0% 0.18(0.18+0.02) -10.0% 2000.4: git status (sparse-v3) 0.04(0.04+0.04) 0.05(0.07+0.04) +25.0% 0.04(0.04+0.05) +0.0% 0.04(0.06+0.04) +0.0% 2000.5: git status (sparse-v4) 0.04(0.03+0.06) 0.04(0.05+0.05) +0.0% 0.05(0.05+0.04) +25.0% 0.05(0.06+0.04) +25.0% 2000.6: git add -A (full-v3) 0.36(0.29+0.05) 0.38(0.28+0.07) +5.6% 0.36(0.31+0.05) +0.0% 0.37(0.31+0.05) +2.8% 2000.7: git add -A (full-v4) 0.34(0.27+0.06) 0.34(0.29+0.05) +0.0% 0.34(0.29+0.04) +0.0% 0.35(0.28+0.06) +2.9% 2000.8: git add -A (sparse-v3) 0.06(0.07+0.04) 0.06(0.05+0.06) +0.0% 0.06(0.09+0.01) +0.0% 0.06(0.08+0.03) +0.0% 2000.9: git add -A (sparse-v4) 0.05(0.05+0.04) 0.05(0.05+0.07) +0.0% 0.05(0.04+0.06) +0.0% 0.06(0.06+0.05) +20.0% 2000.10: git add . (full-v3) 0.38(0.31+0.05) 0.37(0.29+0.06) -2.6% 0.37(0.30+0.07) -2.6% 0.37(0.29+0.06) -2.6% 2000.11: git add . (full-v4) 0.35(0.31+0.04) 0.35(0.29+0.07) +0.0% 0.35(0.29+0.05) +0.0% 0.34(0.29+0.06) -2.9% 2000.12: git add . (sparse-v3) 0.06(0.06+0.05) 0.06(0.05+0.06) +0.0% 0.06(0.07+0.05) +0.0% 0.06(0.09+0.03) +0.0% 2000.13: git add . (sparse-v4) 0.06(0.06+0.06) 0.06(0.07+0.04) +0.0% 0.05(0.06+0.05) -16.7% 0.05(0.05+0.07) -16.7% 2000.14: git commit -a -m A (full-v3) 0.48(0.37+0.08) 0.45(0.36+0.08) -6.2% 0.45(0.35+0.09) -6.2% 0.44(0.36+0.07) -8.3% 2000.15: git commit -a -m A (full-v4) 0.45(0.40+0.06) 0.43(0.34+0.07) -4.4% 0.45(0.37+0.06) +0.0% 0.42(0.36+0.05) -6.7% 2000.16: git commit -a -m A (sparse-v3) 0.05(0.05+0.06) 0.05(0.05+0.03) +0.0% 0.05(0.06+0.06) +0.0% 0.05(0.04+0.06) +0.0% 2000.17: git commit -a -m A (sparse-v4) 0.05(0.06+0.03) 0.05(0.06+0.04) +0.0% 0.06(0.07+0.05) +20.0% 0.05(0.04+0.06) +0.0% 2000.18: git checkout -f - (full-v3) 0.55(0.43+0.08) 0.54(0.46+0.05) -1.8% 0.55(0.46+0.07) +0.0% 0.54(0.40+0.10) -1.8% 2000.19: git checkout -f - (full-v4) 0.55(0.41+0.09) 0.50(0.40+0.09) -9.1% 0.51(0.46+0.05) -7.3% 0.51(0.44+0.06) -7.3% 2000.20: git checkout -f - (sparse-v3) 0.06(0.09+0.03) 0.06(0.08+0.03) +0.0% 0.06(0.06+0.05) +0.0% 0.07(0.09+0.03) +16.7% 2000.21: git checkout -f - (sparse-v4) 0.06(0.08+0.04) 0.05(0.07+0.05) -16.7% 0.05(0.07+0.04) -16.7% 0.06(0.09+0.03) +0.0% ``` All of the above were already integrated. ``` 2000.22: git reset (full-v3) 0.41(0.32+0.06) 0.40(0.31+0.06) -2.4% 0.41(0.33+0.05) +0.0% 0.42(0.34+0.04) +2.4% 2000.23: git reset (full-v4) 0.37(0.32+0.05) 0.35(0.30+0.05) -5.4% 0.37(0.30+0.05) +0.0% 0.35(0.31+0.03) -5.4% 2000.24: git reset (sparse-v3) 0.68(0.65+0.05) 0.55(0.52+0.04) -19.1% 0.04(0.05+0.04) -94.1% 0.04(0.05+0.04) -94.1% 2000.25: git reset (sparse-v4) 0.70(0.65+0.05) 0.54(0.50+0.06) -22.9% 0.04(0.07+0.01) -94.3% 0.03(0.05+0.05) -95.7% 2000.26: git reset --hard (full-v3) 0.54(0.43+0.07) 0.53(0.43+0.06) -1.9% 0.55(0.46+0.05) +1.9% 0.55(0.44+0.06) +1.9% 2000.27: git reset --hard (full-v4) 0.50(0.45+0.03) 0.50(0.43+0.05) +0.0% 0.49(0.41+0.06) -2.0% 0.50(0.42+0.05) +0.0% 2000.28: git reset --hard (sparse-v3) 0.83(0.76+0.06) 0.68(0.62+0.05) -18.1% 0.07(0.05+0.02) -91.6% 0.07(0.05+0.02) -91.6% 2000.29: git reset --hard (sparse-v4) 0.80(0.75+0.05) 0.69(0.62+0.06) -13.8% 0.07(0.04+0.02) -91.2% 0.07(0.04+0.03) -91.2% ``` As expected, `git reset [--hard]` improves with the sparse index integration, but remains constant across the full index case. ``` 2000.30: git update-index --add --remove (full-v3) 0.03(0.01+0.01) 0.03(0.02+0.01) +0.0% 0.03(0.02+0.01) +0.0% 0.03(0.01+0.01) +0.0% 2000.31: git update-index --add --remove (full-v4) 0.03(0.02+0.01) 0.03(0.02+0.01) +0.0% 0.03(0.03+0.00) +0.0% 0.03(0.02+0.01) +0.0% 2000.32: git update-index --add --remove (sparse-v3) 0.57(0.54+0.02) 0.43(0.42+0.00) -24.6% 0.44(0.41+0.03) -22.8% 0.44(0.42+0.01) -22.8% 2000.33: git update-index --add --remove (sparse-v4) 0.56(0.52+0.04) 0.43(0.42+0.01) -23.2% 0.44(0.42+0.02) -21.4% 0.42(0.41+0.01) -25.0% ``` These do not change significantly because #423 is not merged. ``` 2000.34: git diff (full-v3) 0.07(0.05+0.03) 0.06(0.05+0.03) -14.3% 0.07(0.05+0.03) +0.0% 0.06(0.05+0.03) -14.3% 2000.35: git diff (full-v4) 0.06(0.05+0.03) 0.06(0.05+0.02) +0.0% 0.06(0.05+0.02) +0.0% 0.06(0.06+0.02) +0.0% 2000.36: git diff (sparse-v3) 0.25(0.23+0.03) 0.17(0.17+0.02) -32.0% 0.18(0.18+0.02) -28.0% 0.01(0.03+0.03) -96.0% 2000.37: git diff (sparse-v4) 0.25(0.22+0.05) 0.16(0.16+0.01) -36.0% 0.18(0.15+0.04) -28.0% 0.01(0.04+0.02) -96.0% 2000.38: git diff --staged (full-v3) 0.03(0.01+0.01) 0.03(0.02+0.01) +0.0% 0.03(0.02+0.01) +0.0% 0.03(0.02+0.00) +0.0% 2000.39: git diff --staged (full-v4) 0.04(0.03+0.01) 0.03(0.02+0.01) -25.0% 0.03(0.03+0.00) -25.0% 0.03(0.03+0.00) -25.0% 2000.40: git diff --staged (sparse-v3) 0.21(0.19+0.01) 0.15(0.13+0.01) -28.6% 0.15(0.14+0.01) -28.6% 0.01(0.01+0.00) -95.2% 2000.41: git diff --staged (sparse-v4) 0.22(0.21+0.01) 0.14(0.11+0.03) -36.4% 0.15(0.13+0.02) -31.8% 0.01(0.01+0.00) -95.5% ``` The `git diff` improvements are measurable. ``` 2000.42: git sparse-checkout reapply (full-v3) 0.63(0.54+0.05) 0.56(0.48+0.04) -11.1% 0.57(0.48+0.03) -9.5% 0.59(0.48+0.05) -6.3% 2000.43: git sparse-checkout reapply (full-v4) 0.60(0.54+0.02) 0.51(0.46+0.03) -15.0% 0.54(0.48+0.02) -10.0% 0.50(0.44+0.04) -16.7% 2000.44: git sparse-checkout reapply (sparse-v3) 0.91(0.86+0.05) 0.05(0.05+0.00) -94.5% 0.06(0.05+0.01) -93.4% 0.06(0.06+0.00) -93.4% 2000.45: git sparse-checkout reapply (sparse-v4) 0.92(0.88+0.04) 0.05(0.05+0.00) -94.6% 0.05(0.05+0.01) -94.6% 0.05(0.04+0.01) -94.6% ``` Finally, the `git sparse-checkout` measurements are also present. This test script is particularly valuable when contributing changes upstream. It can be good to start by adding the lines to the performance test in an early commit, then demonstrating the performance change by copying the necessary lines from the output table into your commit message.

diff: enable and test the sparse index

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ldennington changed the title ~~sparse-index diff integration: initial attempt~~ diff: enable and test the sparse index Sep 10, 2021

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Sparse index: add more performance tests #425

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