Merge branch 'tb/pseudo-merge-reachability-bitmap'

The pseudo-merge reachability bitmap to help more efficient storage
of the reachability bitmap in a repository with too many refs has
been added.

* tb/pseudo-merge-reachability-bitmap: (26 commits)
  pack-bitmap.c: ensure pseudo-merge offset reads are bounded
  Documentation/technical/bitmap-format.txt: add missing position table
  t/perf: implement performance tests for pseudo-merge bitmaps
  pseudo-merge: implement support for finding existing merges
  ewah: `bitmap_equals_ewah()`
  pack-bitmap: extra trace2 information
  pack-bitmap.c: use pseudo-merges during traversal
  t/test-lib-functions.sh: support `--notick` in `test_commit_bulk()`
  pack-bitmap: implement test helpers for pseudo-merge
  ewah: implement `ewah_bitmap_popcount()`
  pseudo-merge: implement support for reading pseudo-merge commits
  pack-bitmap.c: read pseudo-merge extension
  pseudo-merge: scaffolding for reads
  pack-bitmap: extract `read_bitmap()` function
  pack-bitmap-write.c: write pseudo-merge table
  pseudo-merge: implement support for selecting pseudo-merge commits
  config: introduce `git_config_double()`
  pack-bitmap: make `bitmap_writer_push_bitmapped_commit()` public
  pack-bitmap: implement `bitmap_writer_has_bitmapped_object_id()`
  pack-bitmap-write: support storing pseudo-merge commits
  ...

1 files changed, 32 insertions, 0 deletions

diff --git a/t/perf/p5333-pseudo-merge-bitmaps.sh b/t/perf/p5333-pseudo-merge-bitmaps.sh
new file mode 100755
index 0000000000..2e8b1d2635
--- /dev/null
+++ b/t/perf/p5333-pseudo-merge-bitmaps.sh
@@ -0,0 +1,32 @@
+#!/bin/sh
+
+test_description='pseudo-merge bitmaps'
+. ./perf-lib.sh
+
+test_perf_large_repo
+
+test_expect_success 'setup' '
+	git \
+		-c bitmapPseudoMerge.all.pattern="refs/" \
+		-c bitmapPseudoMerge.all.threshold=now \
+		-c bitmapPseudoMerge.all.stableThreshold=never \
+		-c bitmapPseudoMerge.all.maxMerges=64 \
+		-c pack.writeBitmapLookupTable=true \
+		repack -adb
+'
+
+test_perf 'git rev-list --count --all --objects (no bitmaps)' '
+	git rev-list --objects --all
+'
+
+test_perf 'git rev-list --count --all --objects (no pseudo-merges)' '
+	GIT_TEST_USE_PSEUDO_MERGES=0 \
+		git rev-list --objects --all --use-bitmap-index
+'
+
+test_perf 'git rev-list --count --all --objects (with pseudo-merges)' '
+	GIT_TEST_USE_PSEUDO_MERGES=1 \
+		git rev-list --objects --all --use-bitmap-index
+'
+
+test_done