diff --git a/t/perf/perf-lib.sh b/t/perf/perf-lib.sh
index 4173eee4de..5406557b7c 100644
--- a/t/perf/perf-lib.sh
+++ b/t/perf/perf-lib.sh
@@ -25,7 +25,29 @@ TEST_OUTPUT_DIRECTORY=$(pwd)
 TEST_NO_CREATE_REPO=t
 TEST_NO_MALLOC_CHECK=t
 
-. ../test-lib.sh
+# While test-lib.sh computes the build directory for us, we also have to do the
+# same thing in order to locate the script via GIT-BUILD-OPTIONS in the first
+# place.
+GIT_BUILD_DIR="${GIT_BUILD_DIR:-$TEST_DIRECTORY/..}"
+if test -f "$GIT_BUILD_DIR/GIT-BUILD-DIR"
+then
+	GIT_BUILD_DIR="$(cat "$GIT_BUILD_DIR/GIT-BUILD-DIR")" || exit 1
+	# On Windows, we must convert Windows paths lest they contain a colon
+	case "$(uname -s)" in
+	*MINGW*)
+		GIT_BUILD_DIR="$(cygpath -au "$GIT_BUILD_DIR")"
+		;;
+	esac
+fi
+
+if test ! -f "$GIT_BUILD_DIR"/GIT-BUILD-OPTIONS
+then
+	echo >&2 'error: GIT-BUILD-OPTIONS missing (has Git been built?).'
+	exit 1
+fi
+
+. "$GIT_BUILD_DIR"/GIT-BUILD-OPTIONS
+. "$GIT_SOURCE_DIR"/t/test-lib.sh
 
 unset GIT_CONFIG_NOSYSTEM
 GIT_CONFIG_SYSTEM="$TEST_DIRECTORY/perf/config"
@@ -324,7 +346,7 @@ test_at_end_hook_ () {
 	if test -z "$GIT_PERF_AGGREGATING_LATER"; then
 		(
 			cd "$TEST_DIRECTORY"/perf &&
-			"$PERL_PATH" ./aggregate.perl --results-dir="$TEST_RESULTS_DIR" $(basename "$0")
+			"$PERL_PATH" "$GIT_SOURCE_DIR"/t/perf/aggregate.perl --results-dir="$TEST_RESULTS_DIR" $(basename "$0")
 		)
 	fi
 }