diff --git a/lualib-src/lualib-core.c b/lualib-src/lualib-core.c
index 663e585..341ff99 100644
--- a/lualib-src/lualib-core.c
+++ b/lualib-src/lualib-core.c
@@ -477,14 +477,16 @@ ltracenew(lua_State *L)
 static int
 ltraceset(lua_State *L)
 {
-	silly_trace_id_t traceid;
-	if lua_isnoneornil(L, 1) {
-		traceid = TRACE_WORKER_ID;
-	} else {
-		traceid = (silly_trace_id_t)luaL_checkinteger(L, 1);
-	}
-	traceid = silly_trace_set(traceid);
-	lua_pushinteger(L, (lua_Integer)traceid);
+ 	silly_trace_id_t traceid;
+	lua_State *co = lua_tothread(L, 1);
+ 	silly_worker_resume(co);
+ 	if lua_isnoneornil(L, 2) {
+ 		traceid = TRACE_WORKER_ID;
+ 	} else {
+		traceid = (silly_trace_id_t)luaL_checkinteger(L, 2);
+ 	}
+ 	traceid = silly_trace_set(traceid);
+ 	lua_pushinteger(L, (lua_Integer)traceid);
 	return 1;
 }
 
diff --git a/lualib/core.lua b/lualib/core.lua
index 19d7cde..4bce402 100644
--- a/lualib/core.lua
+++ b/lualib/core.lua
@@ -52,7 +52,7 @@ local function task_resume(t, ...)
 	local save = task_running
 	task_status[t] = "RUN"
 	task_running = t
-	local traceid = trace_set(task_traceid[t])
+	local traceid = trace_set(t, task_traceid[t])
 	local ok, err = coresume(t, ...)
 	trace_set(traceid)
 	task_running = save
@@ -89,7 +89,7 @@ end
 
 function core.trace(id)
 	task_traceid[task_running] = id
-	return (trace_set(id))
+	return (trace_set(task_running, id))
 end
 
 function core.error(errmsg)
diff --git a/silly-src/silly_monitor.c b/silly-src/silly_monitor.c
index 0138c56..93b1d76 100644
--- a/silly-src/silly_monitor.c
+++ b/silly-src/silly_monitor.c
@@ -2,47 +2,28 @@
 #include "atomic.h"
 #include "compiler.h"
 #include "silly_log.h"
+#include "silly_worker.h"
 #include "silly_monitor.h"
 
 struct monitor {
-	unsigned int process_id;
-	unsigned int check_id;
-	int msgtype;
+	uint32_t check_id;
 } M;
 
-static const char *msgname[] = {
-	"NIL",
-	"EXPIRE",
-	"ACCEPT",
-	"CLOSE",
-	"CONNECTED",
-	"TCPDATA",
-	"UDPDATA",
-};
-
 void
 silly_monitor_init()
 {
-	M.process_id = 0;
 	M.check_id = 0;
-	M.msgtype = 0;
 }
 
 void
 silly_monitor_check()
 {
-	if (M.msgtype != 0 && unlikely(M.check_id == M.process_id)) {
-		silly_log_warn("[monitor] message of %s processed slowly\n",
-			msgname[M.msgtype]);
+	uint32_t check_id = silly_worker_processid();
+	if (unlikely(M.check_id == check_id)) {
+		silly_worker_warnendless();
 	}
-	M.check_id = M.process_id;
+	M.check_id = check_id;
 }
 
-void
-silly_monitor_trigger(int msgtype)
-{
-	M.msgtype = msgtype;
-	atomic_add(&M.process_id, 1);
-}
 
 
diff --git a/silly-src/silly_monitor.h b/silly-src/silly_monitor.h
index 849c5ff..a65976d 100644
--- a/silly-src/silly_monitor.h
+++ b/silly-src/silly_monitor.h
@@ -3,7 +3,6 @@
 
 void silly_monitor_init();
 void silly_monitor_check();
-void silly_monitor_trigger(int msgtype);
 
 
 #endif
diff --git a/silly-src/silly_worker.c b/silly-src/silly_worker.c
index 4da2121..43659da 100644
--- a/silly-src/silly_worker.c
+++ b/silly-src/silly_worker.c
@@ -7,6 +7,7 @@
 
 #include "silly.h"
 #include "compiler.h"
+#include "atomic.h"
 #include "silly_log.h"
 #include "silly_malloc.h"
 #include "silly_queue.h"
@@ -20,15 +21,19 @@ struct silly_worker {
 	int argc;
 	char **argv;
 	lua_State *L;
+	lua_State *running;
 	uint32_t id;
+	uint32_t process_id;
 	size_t maxmsg;
+	lua_Hook oldhook;
+	int oldmask;
+	int oldcount;
 	struct silly_queue *queue;
 	void (*callback)(lua_State *L, struct silly_message *msg);
 };
 
 struct silly_worker *W;
 
-
 void
 silly_worker_push(struct silly_message *msg)
 {
@@ -47,6 +52,7 @@ silly_worker_dispatch()
 	struct silly_message *msg;
 	struct silly_message *tmp;
 	msg = silly_queue_pop(W->queue);
+	atomic_add(&W->process_id, 1);
 	if (msg == NULL) {
 #ifdef LUA_GC_STEP
 		lua_gc(W->L, LUA_GCSTEP, LUA_GC_STEP);
@@ -55,7 +61,7 @@ silly_worker_dispatch()
 	}
 	do {
 		do {
-			silly_monitor_trigger(msg->type);
+			atomic_add(&W->process_id, 1);
 			W->callback(W->L, msg);
 			tmp = msg;
 			msg = msg->next;
@@ -63,7 +69,6 @@ silly_worker_dispatch()
 		} while (msg);
 		msg = silly_queue_pop(W->queue);
 	} while (msg);
-	silly_monitor_trigger(0);
 	W->maxmsg = WARNING_THRESHOLD;
 	return ;
 }
@@ -213,6 +218,40 @@ silly_worker_args(int *argc)
 	return W->argv;
 }
 
+void
+silly_worker_resume(lua_State *L)
+{
+	W->running = L;
+}
+
+
+uint32_t
+silly_worker_processid()
+{
+	return W->process_id;
+}
+
+static void warn_hook(lua_State *L, lua_Debug *ar)
+{
+	(void)ar;
+	int top = lua_gettop(L);;
+	luaL_traceback(L, L, "maybe in an endless loop.", 1);
+	silly_log_warn("[worker] %s\n", lua_tostring(L, -1));
+	lua_settop(L, top);
+	lua_sethook(L,W->oldhook,W->oldmask,W->oldcount);
+}
+
+void
+silly_worker_warnendless()
+{
+	if (W->running == NULL)
+		return;
+	W->oldhook=lua_gethook(W->running);
+	W->oldmask=lua_gethookmask(W->running);
+	W->oldcount=lua_gethookcount(W->running);
+	lua_sethook(W->running,warn_hook,LUA_MASKCALL | LUA_MASKRET | LUA_MASKCOUNT,1);
+}
+
 void
 silly_worker_exit()
 {
diff --git a/silly-src/silly_worker.h b/silly-src/silly_worker.h
index 235117f..a736c01 100644
--- a/silly-src/silly_worker.h
+++ b/silly-src/silly_worker.h
@@ -1,5 +1,6 @@
 #ifndef _SILLY_WORKER_H
 #define _SILLY_WORKER_H
+#include <lua.h>
 
 struct silly_message;
 struct lua_State;
@@ -15,6 +16,10 @@ void silly_worker_dispatch();
 uint32_t silly_worker_genid();
 size_t silly_worker_msgsize();
 
+uint32_t silly_worker_processid();
+void silly_worker_resume(lua_State *L);
+void silly_worker_warnendless();
+
 char **silly_worker_args(int *argc);
 
 void silly_worker_callback(void (*callback)(struct lua_State *L, struct silly_message *msg));