diff --git a/lualib-src/lua-profile.c b/lualib-src/lua-profile.c
index bf0ac74b..6522b9fa 100644
--- a/lualib-src/lua-profile.c
+++ b/lualib-src/lua-profile.c
@@ -107,7 +107,7 @@ lstop(lua_State *L) {
 	total_time += ti;
 	lua_pushnumber(L, total_time);
 #ifdef DEBUG_LOG
-	fprintf(stderr, "PROFILE [%p] stop (%lf / %lf)\n", lua_tothread(L,1), ti, total_time);
+	fprintf(stderr, "PROFILE [%p] stop (%lf/%lf)\n", lua_tothread(L,1), ti, total_time);
 #endif
 
 	return 1;
@@ -115,18 +115,15 @@ lstop(lua_State *L) {
 
 static int
 timing_resume(lua_State *L) {
-#ifdef DEBUG_LOG
-	lua_State *from = lua_tothread(L, -1);
-#endif
+	lua_pushvalue(L, -1);
 	lua_rawget(L, lua_upvalueindex(2));
 	if (lua_isnil(L, -1)) {		// check total time
-		lua_pop(L,1);
+		lua_pop(L,2);	// pop from coroutine
 	} else {
 		lua_pop(L,1);
-		lua_pushvalue(L,1);
 		double ti = get_time();
 #ifdef DEBUG_LOG
-		fprintf(stderr, "PROFILE [%p] resume\n", from);
+		fprintf(stderr, "PROFILE [%p] resume %lf\n", lua_tothread(L, -1), ti);
 #endif
 		lua_pushnumber(L, ti);
 		lua_rawset(L, lua_upvalueindex(1));	// set start time
@@ -147,7 +144,7 @@ lresume(lua_State *L) {
 static int
 lresume_co(lua_State *L) {
 	luaL_checktype(L, 2, LUA_TTHREAD);
-	lua_rotate(L, 2, -1);
+	lua_rotate(L, 2, -1);	// 'from' coroutine rotate to the top(index -1)
 
 	return timing_resume(L);
 }