diff --git a/util/async.lua b/util/async.lua
index 8b92c878d..012cfd87b 100644
--- a/util/async.lua
+++ b/util/async.lua
@@ -1,6 +1,5 @@
 local log = require "util.logger".init("util.async");
 local new_id = require "util.id".short;
-local timer = require "util.timer";
 
 local function checkthread()
 	local thread, main = coroutine.running();
@@ -226,16 +225,9 @@ local function ready()
 	return pcall(checkthread);
 end
 
-local function sleep(s)
-	local wait, done = waiter();
-	timer.add_task(s, done);
-	wait();
-end
-
 return {
 	ready = ready;
 	waiter = waiter;
 	guarder = guarder;
 	runner = runner;
-	sleep = sleep;
 };
diff --git a/util/timer.lua b/util/timer.lua
index ff8340687..70678ab26 100644
--- a/util/timer.lua
+++ b/util/timer.lua
@@ -10,6 +10,7 @@ local indexedbheap = require "util.indexedbheap";
 local log = require "util.logger".init("timer");
 local server = require "net.server";
 local get_time = require "util.time".now
+local async = require "util.async";
 local type = type;
 local debug_traceback = debug.traceback;
 local tostring = tostring;
@@ -102,9 +103,16 @@ local function reschedule(id, delay)
 	return id;
 end
 
+local function sleep(s)
+	local wait, done = async.waiter();
+	add_task(s, done);
+	wait();
+end
+
 return {
 	add_task = add_task;
 	stop = stop;
 	reschedule = reschedule;
+	sleep = sleep;
 };