diff --git a/src/xtimer.rs b/src/xtimer.rs
index 5326ad7..c96c0a3 100644
--- a/src/xtimer.rs
+++ b/src/xtimer.rs
@@ -2,6 +2,8 @@ use std::rc::{Rc, Weak};
 use std::cell::RefCell;
 use std::any::Any;
 use std::cmp;
+use std::time::{Duration, Instant};
+
 use r9_macro::SharedFromSelf;
 use r9_macro_derive::SharedFromSelf;
 
@@ -307,9 +309,7 @@ impl XTimer {
                     expire_time: i32,
                     cb: TimerCb,
                     attacher: Option<XTimerAttacherRp>) -> XTimerWp {
-        println!("2222");
         let t = self.new_timer_list();
-        println!("111111");
         t.borrow_mut().cb = Some(cb);
         t.borrow_mut().timer_type = timer_type;
         t.borrow_mut().expire_time = expire_time;
@@ -358,7 +358,6 @@ impl XTimer {
             index = (t.borrow().expires >> (TVR_BITS + 3 * TVN_BITS)) & (TVN_MASK as i64);
             vec = &self.tv5[index as usize];
         }
-        println!("add2 idx:{} index:{}", idx, index);
         crate::ListHead::<TimerList>::add_tail(&vec, &t.borrow_mut().timer_entry);
     }
 
@@ -514,7 +513,8 @@ impl XTimer {
     }
 
     fn gc_timer(&mut self, e: TimerEvent, _args: Option<Vec<Rc::<dyn Any>>>) {
-        println!("aaaaa");
+        let now = Instant::now();
+        println!("now: {:?}", now);
         match e {
             TimerEvent::Exec => {
                 while self.free_timer_num > self.cache_timer_num &&