[PATCH] perf: disable automatic housekeeping

["René Scharfe" <l.s.r@web.de>]

Turn off automatic background maintenance for perf tests by default to
avoid interference with performance measurements.  Do that by using the
new file t/perf/config and using it as the system config file for perf
tests.  Future tests intended to measure gc performance can override
the setting locally or call "git gc" explicitly.

This fixes a breakage in p2000 caused by gc automatically emptying the
reflog due its fake dates from 2005 being older than 90 days.

Helped-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: René Scharfe <l.s.r@web.de>
---
 t/perf/config      | 2 ++
 t/perf/perf-lib.sh | 4 ++++
 2 files changed, 6 insertions(+)
 create mode 100644 t/perf/config

diff --git a/t/perf/config b/t/perf/config
new file mode 100644
index 0000000000..b92768b039
--- /dev/null
+++ b/t/perf/config
@@ -0,0 +1,2 @@
+[gc]
+	auto = 0
diff --git a/t/perf/perf-lib.sh b/t/perf/perf-lib.sh
index f74cfd35d6..4c4c568a37 100644
--- a/t/perf/perf-lib.sh
+++ b/t/perf/perf-lib.sh
@@ -27,6 +27,10 @@ TEST_NO_MALLOC_CHECK=t

 . ../test-lib.sh

+unset GIT_CONFIG_NOSYSTEM
+GIT_CONFIG_SYSTEM="$TEST_DIRECTORY/perf/config"
+export GIT_CONFIG_SYSTEM
+
 if test -n "$GIT_TEST_INSTALLED" -a -z "$PERF_SET_GIT_TEST_INSTALLED"
 then
 	error "Do not use GIT_TEST_INSTALLED with the perf tests.
--
2.33.0