From: Jeff Hostetler <jeffhost@xxxxxxxxxxxxx>
Created test helper to measure read_index() with and without
core.checksumindex set and report performance.
Signed-off-by: Jeff Hostetler <jeffhost@xxxxxxxxxxxxx>
---
Makefile | 1 +
t/helper/.gitignore | 1 +
t/helper/test-core-checksum-index.c | 77 +++++++++++++++++++++++++++++++++++++
3 files changed, 79 insertions(+)
create mode 100644 t/helper/test-core-checksum-index.c
diff --git a/Makefile b/Makefile
index 9ec6065..6049427 100644
--- a/Makefile
+++ b/Makefile
@@ -607,6 +607,7 @@ PROGRAMS += $(patsubst %.o,git-%$X,$(PROGRAM_OBJS))
TEST_PROGRAMS_NEED_X += test-chmtime
TEST_PROGRAMS_NEED_X += test-ctype
TEST_PROGRAMS_NEED_X += test-config
+TEST_PROGRAMS_NEED_X += test-core-checksum-index
TEST_PROGRAMS_NEED_X += test-date
TEST_PROGRAMS_NEED_X += test-delta
TEST_PROGRAMS_NEED_X += test-dump-cache-tree
diff --git a/t/helper/.gitignore b/t/helper/.gitignore
index d6e8b36..f651a6b 100644
--- a/t/helper/.gitignore
+++ b/t/helper/.gitignore
@@ -1,6 +1,7 @@
/test-chmtime
/test-ctype
/test-config
+/test-core-checksum-index
/test-date
/test-delta
/test-dump-cache-tree
diff --git a/t/helper/test-core-checksum-index.c b/t/helper/test-core-checksum-index.c
new file mode 100644
index 0000000..0452dc2
--- /dev/null
+++ b/t/helper/test-core-checksum-index.c
@@ -0,0 +1,77 @@
+#include "cache.h"
+#include "parse-options.h"
+
+uint64_t time_runs(int do_checksum, int count)
+{
+ uint64_t t0, t1;
+ uint64_t sum = 0;
+ uint64_t avg;
+ int i;
+
+ git_config_set_gently("core.checksumindex",
+ (do_checksum ? "true" : "false"));
+
+ for (i = 0; i < count; i++) {
+ t0 = getnanotime();
+ read_cache();
+ t1 = getnanotime();
+
+ sum += (t1 - t0);
+
+ printf("%f %d [cache_nr %d]\n",
+ ((double)(t1 - t0))/1000000000,
+ do_checksum,
+ the_index.cache_nr);
+ fflush(stdout);
+
+ discard_cache();
+ }
+
+ avg = sum / count;
+ if (count > 1) {
+ printf("%f %d avg\n",
+ (double)avg/1000000000,
+ do_checksum);
+ fflush(stdout);
+ }
+
+ return avg;
+}
+
+int cmd_main(int argc, const char **argv)
+{
+ int original_do_checksum;
+ int count = 1;
+ const char *usage[] = {
+ "test-core-checksum-index",
+ NULL
+ };
+ struct option options[] = {
+ OPT_INTEGER('c', "count", &count, "number of passes"),
+ OPT_END(),
+ };
+ const char *prefix;
+ uint64_t avg_0, avg_1;
+
+ prefix = setup_git_directory();
+ argc = parse_options(argc, argv, prefix, options, usage, 0);
+
+ if (count < 1)
+ die("count must greater than zero");
+
+ /* throw away call to get the index in the disk cache */
+ read_cache();
+ discard_cache();
+
+ git_config_get_bool("core.checksumindex", &original_do_checksum);
+
+ avg_1 = time_runs(1, count);
+ avg_0 = time_runs(0, count);
+
+ git_config_set_gently("core.checksumindex",
+ ((original_do_checksum) ? "true" : "false"));
+
+ if (avg_0 >= avg_1)
+ die("skipping index checksum verification did not help");
+ return 0;
+}
--
2.9.3