core.fsyncmethod: performance tests for add and stash

Add a basic performance test for "git add" and "git stash" of a lot of
new objects with various fsync settings. This shows the benefit of batch
mode relative to an ordinary stash command.

Signed-off-by: Neeraj Singh <neerajsi@microsoft.com>

Author: neerajsi-msft

t/perf/p3700-add.sh

@@ -0,0 +1,55 @@
+#!/bin/sh
+#
+# This test measures the performance of adding new files to the object database
+# and index. The test was originally added to measure the effect of the
+# core.fsyncObjectFiles=batch mode, which is why we are testing different values
+# of that setting explicitly and creating a lot of unique objects.
+
+test_description="Tests performance of add"
+
+. ./perf-lib.sh
+
+. $TEST_DIRECTORY/lib-unique-files.sh
+
+test_perf_default_repo
+test_checkout_worktree
+
+dir_count=10
+files_per_dir=50
+total_files=$((dir_count * files_per_dir))
+
+# We need to create the files each time we run the perf test, but
+# we do not want to measure the cost of creating the files, so run
+# the test once.
+if test "${GIT_PERF_REPEAT_COUNT-1}" -ne 1
+then
+	echo "warning: Setting GIT_PERF_REPEAT_COUNT=1" >&2
+	GIT_PERF_REPEAT_COUNT=1
+fi
+
+for m in false true batch
+do
+	test_expect_success "create the files for object_fsyncing=$m" '
+		git reset --hard &&
+		# create files across directories
+		test_create_unique_files $dir_count $files_per_dir files
+	'
+
+	case $m in
+	false)
+		FSYNC_CONFIG='-c core.fsync=default,-loose-object -c core.fsyncmethod=fsync'
+		;;
+	true)
+		FSYNC_CONFIG='-c core.fsync=default,loose-object -c core.fsyncmethod=fsync'
+		;;
+	batch)
+		FSYNC_CONFIG='-c core.fsync=default,loose-object -c core.fsyncmethod=batch'
+		;;
+	esac
+
+	test_perf "add $total_files files (object_fsyncing=$m)" "
+		git $FSYNC_CONFIG add files
+	"
+done
+
+test_done

t/perf/p3900-stash.sh

@@ -0,0 +1,58 @@
+#!/bin/sh
+#
+# This test measures the performance of adding new files to the object database
+# and index. The test was originally added to measure the effect of the
+# core.fsyncObjectFiles=batch mode, which is why we are testing different values
+# of that setting explicitly and creating a lot of unique objects.
+
+test_description="Tests performance of stash"
+
+. ./perf-lib.sh
+
+. $TEST_DIRECTORY/lib-unique-files.sh
+
+test_perf_default_repo
+test_checkout_worktree
+
+dir_count=10
+files_per_dir=50
+total_files=$((dir_count * files_per_dir))
+
+# We need to create the files each time we run the perf test, but
+# we do not want to measure the cost of creating the files, so run
+# the test once.
+if test "${GIT_PERF_REPEAT_COUNT-1}" -ne 1
+then
+	echo "warning: Setting GIT_PERF_REPEAT_COUNT=1" >&2
+	GIT_PERF_REPEAT_COUNT=1
+fi
+
+for m in false true batch
+do
+	test_expect_success "create the files for object_fsyncing=$m" '
+		git reset --hard &&
+		# create files across directories
+		test_create_unique_files $dir_count $files_per_dir files
+	'
+
+	case $m in
+	false)
+		FSYNC_CONFIG='-c core.fsync=default,-loose-object -c core.fsyncmethod=fsync'
+		;;
+	true)
+		FSYNC_CONFIG='-c core.fsync=default,loose-object -c core.fsyncmethod=fsync'
+		;;
+	batch)
+		FSYNC_CONFIG='-c core.fsync=default,loose-object -c core.fsyncmethod=batch'
+		;;
+	esac
+
+	# We only stash files in the 'files' subdirectory since
+	# the perf test infrastructure creates files in the
+	# current working directory that need to be preserved
+	test_perf "stash $total_files files (object_fsyncing=$m)" "
+		git $FSYNC_CONFIG stash push -u -- files
+	"
+done
+
+test_done