diff --git a/src/arch/x86_64/interrupt/handler.rs b/src/arch/x86_64/interrupt/handler.rs
index ac2c8b7..3dd83da 100644
--- a/src/arch/x86_64/interrupt/handler.rs
+++ b/src/arch/x86_64/interrupt/handler.rs
@@ -71,21 +71,9 @@ interrupt!(com2, {
     ack(IRQ_COM2);
 });
 
-use spin::Mutex;
-// FIXME: Deadlock
-//static TICK: Mutex<usize> = Mutex::new(0);
-
 interrupt_switch!(timer, stack, rsp, {
-//    let mut tick = TICK.lock();
-//    *tick += 1;
-//    let tick = *tick;
-    static mut tick: usize = 0;
-    unsafe{ tick += 1; }
-    if tick % 100 == 0 {
-        info!("\nInterupt: Timer\ntick = {}", tick);
-        use process;
-        process::schedule(&mut rsp);
-    }
+    use schedule;
+    schedule::timer_handler(stack, &mut rsp);
     ack(IRQ_TIMER);
 });
 
diff --git a/src/fs.rs b/src/fs.rs
index e14fe72..8081805 100644
--- a/src/fs.rs
+++ b/src/fs.rs
@@ -38,7 +38,7 @@ pub fn load_sfs() {
     trace!("Loading programs: {:?}", files);
 
 //    for name in files.iter().filter(|&f| f != "." && f != "..") {
-    for name in files.iter().filter(|&f| f == "forktest") {
+    for name in files.iter().filter(|&f| f == "sleep") {
         static mut BUF: [u8; 64 << 12] = [0; 64 << 12];
         let file = root.borrow().lookup(name.as_str()).unwrap();
         let len = file.borrow().read_at(0, unsafe { &mut BUF }).unwrap();
diff --git a/src/lib.rs b/src/lib.rs
index 3b45caf..f0e614d 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -49,6 +49,7 @@ mod consts;
 mod process;
 mod syscall;
 mod fs;
+mod schedule;
 
 #[allow(dead_code)]
 #[cfg(target_arch = "x86_64")]
diff --git a/src/process/mod.rs b/src/process/mod.rs
index fe93c1f..f4af443 100644
--- a/src/process/mod.rs
+++ b/src/process/mod.rs
@@ -95,6 +95,11 @@ pub fn sys_exit(rsp: &mut usize, error_code: ErrorCode) -> i32 {
     0
 }
 
+pub fn sys_sleep(rsp: &mut usize, time: usize) -> i32 {
+    info!("sleep: {} ticks", time);
+    unimplemented!()
+}
+
 pub fn add_user_process(name: impl AsRef<str>, data: &[u8]) {
     let mut processor = PROCESSOR.try().unwrap().lock();
     let mut mc = MC.try().unwrap().lock();
diff --git a/src/schedule.rs b/src/schedule.rs
new file mode 100644
index 0000000..80bf63a
--- /dev/null
+++ b/src/schedule.rs
@@ -0,0 +1,89 @@
+use spin::Mutex;
+use alloc::BinaryHeap;
+use arch::interrupt::TrapFrame;
+use core::cmp::{Ordering, PartialOrd};
+
+pub fn get_time() -> i32 {
+    info!("get_time:");
+    EVENT_HUB.get_time() as i32
+}
+
+pub fn timer_handler(tf: &TrapFrame, rsp: &mut usize) {
+    // Store rsp to global for `schedule`
+    *RSP.lock() = Some(*rsp);
+
+    EVENT_HUB.tick();
+
+    // Take rsp from global
+    *rsp = RSP.lock().take().unwrap();
+}
+
+static RSP: Mutex<Option<usize>> = Mutex::new(None);
+
+fn schedule() {
+    info!("Schedule at time {}", EVENT_HUB.get_time());
+    use process;
+    process::schedule(RSP.lock().as_mut().unwrap());
+
+    // Repeat
+    EVENT_HUB.add(100, schedule);
+}
+
+lazy_static! {
+    static ref EVENT_HUB: EventHub = {
+        let e = EventHub::default();
+        e.add(100, schedule);
+        info!("EventHub: init");
+        e
+    };
+}
+
+type Time = usize;
+type TimerHandler = fn();
+
+#[derive(Debug, Eq, PartialEq)]
+struct Timer {
+    time: Time,
+    handler: TimerHandler,
+}
+
+impl PartialOrd for Timer {
+    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+        other.time.partial_cmp(&self.time)
+    }
+}
+
+impl Ord for Timer {
+    fn cmp(&self, other: &Self) -> Ordering {
+        self.partial_cmp(&other).unwrap()
+    }
+}
+
+#[derive(Default)]
+struct EventHub {
+    tick: Mutex<Time>,
+    timers: Mutex<BinaryHeap<Timer>>,
+}
+
+impl EventHub {
+    fn tick(&self) {
+        *self.tick.lock() += 1;
+        let tick = *self.tick.lock();
+        loop {
+            match self.timers.lock().peek() {
+                None => return,
+                Some(timer) if timer.time != tick => return,
+                _ => {}
+            }
+            let timer = self.timers.lock().pop().unwrap();
+            (timer.handler)();
+        }
+    }
+    pub fn add(&self, time_after: Time, handler: TimerHandler) {
+        let time = self.get_time() + time_after;
+        self.timers.lock().push(Timer { time, handler });
+    }
+    pub fn get_time(&self) -> Time {
+        *self.tick.lock()
+    }
+}
\ No newline at end of file
diff --git a/src/syscall.rs b/src/syscall.rs
index aa2690c..e68c241 100644
--- a/src/syscall.rs
+++ b/src/syscall.rs
@@ -31,15 +31,19 @@ pub unsafe fn syscall(tf: &TrapFrame, rsp: &mut usize, is32: bool) -> i32 {
             process::sys_exit(rsp, args[0]),
         Syscall::Ucore(UCORE_SYS_GETPID) =>
             process::sys_getpid(),
+        Syscall::Ucore(UCORE_SYS_SLEEP) =>
+            process::sys_sleep(rsp, args[0]),
+        Syscall::Ucore(UCORE_SYS_GETTIME) =>
+            schedule::get_time(),
         Syscall::Ucore(UCORE_SYS_PUTC) =>
             {
                 print!("{}", args[0] as u8 as char);
                 0
-            },
+            }
         _ => {
-            warn!("unknown syscall {:#x?}", id);
+            error!("unknown syscall {:#x?}", id);
             -1
-        },
+        }
     }
 }