diff --git a/src/shrpx.cc b/src/shrpx.cc
index f1abba0d..ed6cf1f7 100644
--- a/src/shrpx.cc
+++ b/src/shrpx.cc
@@ -1032,6 +1032,7 @@ void fill_default_config() {
       // Default accept() backlog
       listenerconf.backlog = 512;
       listenerconf.host_unix = false;
+      listenerconf.timeout.sleep = 30_s;
     }
   }
 
diff --git a/src/shrpx_accept_handler.cc b/src/shrpx_accept_handler.cc
index 0d448306..418a3bf0 100644
--- a/src/shrpx_accept_handler.cc
+++ b/src/shrpx_accept_handler.cc
@@ -87,7 +87,7 @@ void AcceptHandler::accept_connection() {
       case ENFILE:
         LOG(WARN) << "acceptor: running out file descriptor; disable acceptor "
                      "temporarily";
-        conn_hnr_->disable_acceptor_temporary(30.);
+        conn_hnr_->sleep_acceptor(get_config()->conn.listener.timeout.sleep);
         break;
       }
 
diff --git a/src/shrpx_connection_handler.cc b/src/shrpx_connection_handler.cc
index 34b10996..1e6504b0 100644
--- a/src/shrpx_connection_handler.cc
+++ b/src/shrpx_connection_handler.cc
@@ -385,7 +385,7 @@ void ConnectionHandler::disable_acceptor() {
   }
 }
 
-void ConnectionHandler::disable_acceptor_temporary(ev_tstamp t) {
+void ConnectionHandler::sleep_acceptor(ev_tstamp t) {
   if (t == 0. || ev_is_active(&disable_acceptor_timer_)) {
     return;
   }
diff --git a/src/shrpx_connection_handler.h b/src/shrpx_connection_handler.h
index 36c5e40b..deec78c8 100644
--- a/src/shrpx_connection_handler.h
+++ b/src/shrpx_connection_handler.h
@@ -98,7 +98,7 @@ public:
   AcceptHandler *get_acceptor6() const;
   void enable_acceptor();
   void disable_acceptor();
-  void disable_acceptor_temporary(ev_tstamp t);
+  void sleep_acceptor(ev_tstamp t);
   void accept_pending_connection();
   void graceful_shutdown_worker();
   void set_graceful_shutdown(bool f);
diff --git a/src/template.h b/src/template.h
index feef5784..7eb11e71 100644
--- a/src/template.h
+++ b/src/template.h
@@ -171,10 +171,18 @@ constexpr unsigned long long operator"" _g(unsigned long long g) {
 
 // User-defined literals for time, converted into double in seconds
 
+// hours
 constexpr double operator"" _h(unsigned long long h) { return h * 60 * 60; }
 
+// minutes
 constexpr double operator"" _min(unsigned long long min) { return min * 60; }
 
+// seconds
+constexpr double operator"" _s(unsigned long long s) { return s; }
+
+// milliseconds
+constexpr double operator"" _ms(unsigned long long ms) { return ms / 1000.; }
+
 // Returns a copy of NULL-terminated string [first, last).
 template <typename InputIt>
 std::unique_ptr<char[]> strcopy(InputIt first, InputIt last) {