[PATCH v2 5/6] bitmap-lookup-table: add performance tests for lookup table

["Abhradeep Chakraborty via GitGitGadget" <gitgitgadget@gmail.com>]

From: Abhradeep Chakraborty <chakrabortyabhradeep79@gmail.com>

Add performance tests to verify the performance of lookup table.

Lookup table makes Git run faster in most of the cases. Below is the
result of `t/perf/p5310-pack-bitmaps.sh`.`perf/p5326-multi-pack-bitmaps.sh`
gives similar result. The repository used in the test is linux kernel.

Test                                                      this tree
--------------------------------------------------------------------------
5310.4: repack to disk (lookup=false)                   295.94(250.45+15.24)
5310.5: simulated clone                                 12.52(5.07+1.40)
5310.6: simulated fetch                                 1.89(2.94+0.24)
5310.7: pack to file (bitmap)                           41.39(20.33+7.20)
5310.8: rev-list (commits)                              0.98(0.59+0.12)
5310.9: rev-list (objects)                              3.40(3.27+0.10)
5310.10: rev-list with tag negated via --not		0.07(0.02+0.04)
         --all (objects)
5310.11: rev-list with negative tag (objects)           0.23(0.16+0.06)
5310.12: rev-list count with blob:none                  0.26(0.18+0.07)
5310.13: rev-list count with blob:limit=1k              6.45(5.94+0.37)
5310.14: rev-list count with tree:0                     0.26(0.18+0.07)
5310.15: simulated partial clone                        4.99(3.19+0.45)
5310.19: repack to disk (lookup=true)                   269.67(174.70+21.33)
5310.20: simulated clone                                11.03(5.07+1.11)
5310.21: simulated fetch                                0.79(0.79+0.17)
5310.22: pack to file (bitmap)                          43.03(20.28+7.43)
5310.23: rev-list (commits)                             0.86(0.54+0.09)
5310.24: rev-list (objects)                             3.35(3.26+0.07)
5310.25: rev-list with tag negated via --not		0.05(0.00+0.03)
	 --all (objects)
5310.26: rev-list with negative tag (objects)           0.22(0.16+0.05)
5310.27: rev-list count with blob:none                  0.22(0.16+0.05)
5310.28: rev-list count with blob:limit=1k              6.45(5.87+0.31)
5310.29: rev-list count with tree:0                     0.22(0.16+0.05)
5310.30: simulated partial clone                        5.17(3.12+0.48)

Test 4-15 are tested without using lookup table. Same tests are
repeated in 16-30 (using lookup table).

Signed-off-by: Abhradeep Chakraborty <chakrabortyabhradeep79@gmail.com>
Mentored-by: Taylor Blau <me@ttaylorr.com>
Co-Mentored-by: Kaartic Sivaraam <kaartic.sivaraam@gmail.com>
---
 t/perf/p5310-pack-bitmaps.sh       | 77 ++++++++++++++-----------
 t/perf/p5326-multi-pack-bitmaps.sh | 93 ++++++++++++++++--------------
 2 files changed, 94 insertions(+), 76 deletions(-)

diff --git a/t/perf/p5310-pack-bitmaps.sh b/t/perf/p5310-pack-bitmaps.sh
index 7ad4f237bc3..6ff42bdd391 100755
--- a/t/perf/p5310-pack-bitmaps.sh
+++ b/t/perf/p5310-pack-bitmaps.sh
@@ -16,39 +16,48 @@ test_expect_success 'setup bitmap config' '
 	git config pack.writebitmaps true
 '
 
-# we need to create the tag up front such that it is covered by the repack and
-# thus by generated bitmaps.
-test_expect_success 'create tags' '
-	git tag --message="tag pointing to HEAD" perf-tag HEAD
-'
-
-test_perf 'repack to disk' '
-	git repack -ad
-'
-
-test_full_bitmap
-
-test_expect_success 'create partial bitmap state' '
-	# pick a commit to represent the repo tip in the past
-	cutoff=$(git rev-list HEAD~100 -1) &&
-	orig_tip=$(git rev-parse HEAD) &&
-
-	# now kill off all of the refs and pretend we had
-	# just the one tip
-	rm -rf .git/logs .git/refs/* .git/packed-refs &&
-	git update-ref HEAD $cutoff &&
-
-	# and then repack, which will leave us with a nice
-	# big bitmap pack of the "old" history, and all of
-	# the new history will be loose, as if it had been pushed
-	# up incrementally and exploded via unpack-objects
-	git repack -Ad &&
-
-	# and now restore our original tip, as if the pushes
-	# had happened
-	git update-ref HEAD $orig_tip
-'
-
-test_partial_bitmap
+test_bitmap () {
+    local enabled="$1"
+
+	# we need to create the tag up front such that it is covered by the repack and
+	# thus by generated bitmaps.
+	test_expect_success 'create tags' '
+		git tag --message="tag pointing to HEAD" perf-tag HEAD
+	'
+
+	test_expect_success "use lookup table: $enabled" '
+		git config pack.writeBitmapLookupTable '"$enabled"'
+	'
+
+	test_perf "repack to disk (lookup=$enabled)" '
+		git repack -ad
+	'
+
+	test_full_bitmap
+
+    test_expect_success "create partial bitmap state (lookup=$enabled)" '
+		# pick a commit to represent the repo tip in the past
+		cutoff=$(git rev-list HEAD~100 -1) &&
+		orig_tip=$(git rev-parse HEAD) &&
+
+		# now kill off all of the refs and pretend we had
+		# just the one tip
+		rm -rf .git/logs .git/refs/* .git/packed-refs &&
+		git update-ref HEAD $cutoff &&
+
+		# and then repack, which will leave us with a nice
+		# big bitmap pack of the "old" history, and all of
+		# the new history will be loose, as if it had been pushed
+		# up incrementally and exploded via unpack-objects
+		git repack -Ad &&
+
+		# and now restore our original tip, as if the pushes
+		# had happened
+		git update-ref HEAD $orig_tip
+    '
+}
+
+test_bitmap false
+test_bitmap true
 
 test_done
diff --git a/t/perf/p5326-multi-pack-bitmaps.sh b/t/perf/p5326-multi-pack-bitmaps.sh
index f2fa228f16a..d67e7437493 100755
--- a/t/perf/p5326-multi-pack-bitmaps.sh
+++ b/t/perf/p5326-multi-pack-bitmaps.sh
@@ -6,47 +6,56 @@ test_description='Tests performance using midx bitmaps'
 
 test_perf_large_repo
 
-# we need to create the tag up front such that it is covered by the repack and
-# thus by generated bitmaps.
-test_expect_success 'create tags' '
-	git tag --message="tag pointing to HEAD" perf-tag HEAD
-'
-
-test_expect_success 'start with bitmapped pack' '
-	git repack -adb
-'
-
-test_perf 'setup multi-pack index' '
-	git multi-pack-index write --bitmap
-'
-
-test_expect_success 'drop pack bitmap' '
-	rm -f .git/objects/pack/pack-*.bitmap
-'
-
-test_full_bitmap
-
-test_expect_success 'create partial bitmap state' '
-	# pick a commit to represent the repo tip in the past
-	cutoff=$(git rev-list HEAD~100 -1) &&
-	orig_tip=$(git rev-parse HEAD) &&
-
-	# now pretend we have just one tip
-	rm -rf .git/logs .git/refs/* .git/packed-refs &&
-	git update-ref HEAD $cutoff &&
-
-	# and then repack, which will leave us with a nice
-	# big bitmap pack of the "old" history, and all of
-	# the new history will be loose, as if it had been pushed
-	# up incrementally and exploded via unpack-objects
-	git repack -Ad &&
-	git multi-pack-index write --bitmap &&
-
-	# and now restore our original tip, as if the pushes
-	# had happened
-	git update-ref HEAD $orig_tip
-'
-
-test_partial_bitmap
+test_bitmap () {
+    local enabled="$1"
+
+	# we need to create the tag up front such that it is covered by the repack and
+	# thus by generated bitmaps.
+	test_expect_success 'create tags' '
+		git tag --message="tag pointing to HEAD" perf-tag HEAD
+	'
+
+	test_expect_success "use lookup table: $enabled" '
+		git config pack.writeBitmapLookupTable '"$enabled"'
+	'
+
+	test_expect_success "start with bitmapped pack (lookup=$enabled)" '
+		git repack -adb
+	'
+
+	test_perf "setup multi-pack index (lookup=$enabled)" '
+		git multi-pack-index write --bitmap
+	'
+
+	test_expect_success "drop pack bitmap (lookup=$enabled)" '
+		rm -f .git/objects/pack/pack-*.bitmap
+	'
+
+	test_full_bitmap
+
+    test_expect_success "create partial bitmap state (lookup=$enabled)" '
+		# pick a commit to represent the repo tip in the past
+		cutoff=$(git rev-list HEAD~100 -1) &&
+		orig_tip=$(git rev-parse HEAD) &&
+
+		# now pretend we have just one tip
+		rm -rf .git/logs .git/refs/* .git/packed-refs &&
+		git update-ref HEAD $cutoff &&
+
+		# and then repack, which will leave us with a nice
+		# big bitmap pack of the "old" history, and all of
+		# the new history will be loose, as if it had been pushed
+		# up incrementally and exploded via unpack-objects
+		git repack -Ad &&
+		git multi-pack-index write --bitmap &&
+
+		# and now restore our original tip, as if the pushes
+		# had happened
+		git update-ref HEAD $orig_tip
+    '
+}
+
+test_bitmap false
+test_bitmap true
 
 test_done
-- 
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