Create helper program test-abbrev to compute the minimum length of a
disambiguating short-sha for 100,000 object ids. The ids are created
by iterating an unsigned int hash_base by a constant hash_delta and
copying hash_base five times across the sha1. Iterating by hash_delta
does not create a duplicate value for over 10,000,000 iterations.
test-abberv demonstrates the performance improvements that will be
shown by later improvements to the find_unique_abberv(). The value of
100,000 is large enough to show the significance of the later
improvements while only taking a few seconds on large repos.
Signed-off-by: Derrick Stolee <dstolee@xxxxxxxxxxxxx>
---
Makefile | 1 +
t/helper/.gitignore | 1 +
t/helper/test-abbrev.c | 23 +++++++++++++++++++++++
t/perf/p0008-abbrev.sh | 12 ++++++++++++
4 files changed, 37 insertions(+)
create mode 100644 t/helper/test-abbrev.c
create mode 100755 t/perf/p0008-abbrev.sh
diff --git a/Makefile b/Makefile
index f2bb7f2f6..081ca05e8 100644
--- a/Makefile
+++ b/Makefile
@@ -633,6 +633,7 @@ X =
PROGRAMS += $(patsubst %.o,git-%$X,$(PROGRAM_OBJS))
+TEST_PROGRAMS_NEED_X += test-abbrev
TEST_PROGRAMS_NEED_X += test-chmtime
TEST_PROGRAMS_NEED_X += test-ctype
TEST_PROGRAMS_NEED_X += test-config
diff --git a/t/helper/.gitignore b/t/helper/.gitignore
index 721650256..80ce7d836 100644
--- a/t/helper/.gitignore
+++ b/t/helper/.gitignore
@@ -1,3 +1,4 @@
+/test-abbrev
/test-chmtime
/test-ctype
/test-config
diff --git a/t/helper/test-abbrev.c b/t/helper/test-abbrev.c
new file mode 100644
index 000000000..cb3551df9
--- /dev/null
+++ b/t/helper/test-abbrev.c
@@ -0,0 +1,23 @@
+#include "cache.h"
+
+int cmd_main(int ac, const char **av)
+{
+ setup_git_directory();
+
+ unsigned int hash_delt = 0x13579BDF;
+ unsigned int hash_base = 0x01020304;
+ struct object_id oid;
+
+ int i, count = 0;
+ int n = sizeof(struct object_id) / sizeof(int);
+ while (count++ < 100000) {
+ for (i = 0; i < n; i++)
+ ((unsigned int*)oid.hash)[i] = hash_base;
+
+ find_unique_abbrev(oid.hash, MINIMUM_ABBREV);
+
+ hash_base += hash_delt;
+ }
+
+ exit(0);
+}
diff --git a/t/perf/p0008-abbrev.sh b/t/perf/p0008-abbrev.sh
new file mode 100755
index 000000000..7c3fad807
--- /dev/null
+++ b/t/perf/p0008-abbrev.sh
@@ -0,0 +1,12 @@
+#!/bin/sh
+
+test_description='Test object disambiguation through abbreviations'
+. ./perf-lib.sh
+
+test_perf_large_repo
+
+test_perf 'find_unique_abbrev()' '
+ test-abbrev
+'
+
+test_done
--
2.14.1.538.g56ec8fc98.dirty
