diff --git a/src/lib.rs b/src/lib.rs
index eaa2938..dfbc7c9 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -91,7 +91,7 @@ pub extern "C" fn rust_main(multiboot_information_address: usize) -> ! {
     unsafe{ arch::interrupt::enable(); }
 
 //    thread::test::unpack();
-    sync::philosopher::philosopher();
+    sync::test::philosopher();
 
     // 直接进入用户态暂不可用：内核代码用户不可访问
 //    unsafe{
diff --git a/src/process/processor.rs b/src/process/processor.rs
index ba3aac7..9810df5 100644
--- a/src/process/processor.rs
+++ b/src/process/processor.rs
@@ -30,7 +30,7 @@ impl Processor {
             kernel_page_table: None,
             next: None,
             // NOTE: max_time_slice <= 5 to ensure 'priority' test pass
-            scheduler: RRScheduler::new(100),
+            scheduler: RRScheduler::new(5),
         }
     }
 
diff --git a/src/sync/mod.rs b/src/sync/mod.rs
new file mode 100644
index 0000000..0b880ac
--- /dev/null
+++ b/src/sync/mod.rs
@@ -0,0 +1,5 @@
+mod mutex;
+mod semaphore;
+pub mod test;
+
+pub use self::mutex::*;
\ No newline at end of file
diff --git a/src/sync.rs b/src/sync/mutex.rs
similarity index 79%
rename from src/sync.rs
rename to src/sync/mutex.rs
index dc6d400..5660b3c 100644
--- a/src/sync.rs
+++ b/src/sync/mutex.rs
@@ -30,7 +30,6 @@ use core::sync::atomic::{AtomicBool, ATOMIC_BOOL_INIT, Ordering};
 use core::cell::UnsafeCell;
 use core::ops::{Deref, DerefMut};
 use core::fmt;
-use arch::interrupt;
 
 pub type SpinLock<T> = Mutex<T, Spin>;
 pub type SpinNoIrqLock<T> = Mutex<T, SpinNoIrq>;
@@ -223,6 +222,8 @@ impl MutexSupport for Spin {
     fn after_unlock(&self) {}
 }
 
+use arch::interrupt;
+
 /// Spin & no-interrupt lock
 #[derive(Debug)]
 pub struct SpinNoIrq;
@@ -273,86 +274,4 @@ impl MutexSupport for Thread {
             t.unpark();
         }
     }
-}
-
-
-pub mod philosopher {
-    //! Dining philosophers problem
-    //!
-    //! The code is borrowed from [RustDoc - Dining Philosophers](https://doc.rust-lang.org/1.6.0/book/dining-philosophers.html)
-
-    use thread;
-    use core::time::Duration;
-    use alloc::{arc::Arc, Vec};
-    use super::ThreadLock as Mutex;
-
-    struct Philosopher {
-        name: &'static str,
-        left: usize,
-        right: usize,
-    }
-
-    impl Philosopher {
-        fn new(name: &'static str, left: usize, right: usize) -> Philosopher {
-            Philosopher {
-                name,
-                left,
-                right,
-            }
-        }
-
-        fn eat(&self, table: &Table) {
-            let _left = table.forks[self.left].lock();
-            let _right = table.forks[self.right].lock();
-
-            println!("{} is eating.", self.name);
-            thread::sleep(Duration::from_secs(1));
-        }
-
-        fn think(&self) {
-            println!("{} is thinking.", self.name);
-            thread::sleep(Duration::from_secs(1));
-        }
-    }
-
-    struct Table {
-        forks: Vec<Mutex<()>>,
-    }
-
-    pub fn philosopher() {
-        let table = Arc::new(Table {
-            forks: vec![
-                Mutex::new(()),
-                Mutex::new(()),
-                Mutex::new(()),
-                Mutex::new(()),
-                Mutex::new(()),
-            ]
-        });
-
-        let philosophers = vec![
-            Philosopher::new("1", 0, 1),
-            Philosopher::new("2", 1, 2),
-            Philosopher::new("3", 2, 3),
-            Philosopher::new("4", 3, 4),
-            Philosopher::new("5", 0, 4),
-        ];
-
-        let handles: Vec<_> = philosophers.into_iter().map(|p| {
-            let table = table.clone();
-
-            thread::spawn(move || {
-                for i in 0..5 {
-                    p.think();
-                    p.eat(&table);
-                    println!("{} iter {} end.", p.name, i);
-                }
-            })
-        }).collect();
-
-        for h in handles {
-            h.join().unwrap();
-        }
-        println!("philosophers dining end");
-    }
 }
\ No newline at end of file
diff --git a/src/sync/semaphore.rs b/src/sync/semaphore.rs
new file mode 100644
index 0000000..6ee6be7
--- /dev/null
+++ b/src/sync/semaphore.rs
@@ -0,0 +1,2 @@
+use super::mutex;
+
diff --git a/src/sync/test.rs b/src/sync/test.rs
new file mode 100644
index 0000000..61a0036
--- /dev/null
+++ b/src/sync/test.rs
@@ -0,0 +1,78 @@
+//! Dining philosophers problem
+//!
+//! The code is borrowed from [RustDoc - Dining Philosophers](https://doc.rust-lang.org/1.6.0/book/dining-philosophers.html)
+
+use thread;
+use core::time::Duration;
+use alloc::{arc::Arc, Vec};
+use sync::ThreadLock as Mutex;
+
+struct Philosopher {
+    name: &'static str,
+    left: usize,
+    right: usize,
+}
+
+impl Philosopher {
+    fn new(name: &'static str, left: usize, right: usize) -> Philosopher {
+        Philosopher {
+            name,
+            left,
+            right,
+        }
+    }
+
+    fn eat(&self, table: &Table) {
+        let _left = table.forks[self.left].lock();
+        let _right = table.forks[self.right].lock();
+
+        println!("{} is eating.", self.name);
+        thread::sleep(Duration::from_secs(1));
+    }
+
+    fn think(&self) {
+        println!("{} is thinking.", self.name);
+        thread::sleep(Duration::from_secs(1));
+    }
+}
+
+struct Table {
+    forks: Vec<Mutex<()>>,
+}
+
+pub fn philosopher() {
+    let table = Arc::new(Table {
+        forks: vec![
+            Mutex::new(()),
+            Mutex::new(()),
+            Mutex::new(()),
+            Mutex::new(()),
+            Mutex::new(()),
+        ]
+    });
+
+    let philosophers = vec![
+        Philosopher::new("1", 0, 1),
+        Philosopher::new("2", 1, 2),
+        Philosopher::new("3", 2, 3),
+        Philosopher::new("4", 3, 4),
+        Philosopher::new("5", 0, 4),
+    ];
+
+    let handles: Vec<_> = philosophers.into_iter().map(|p| {
+        let table = table.clone();
+
+        thread::spawn(move || {
+            for i in 0..5 {
+                p.think();
+                p.eat(&table);
+                println!("{} iter {} end.", p.name, i);
+            }
+        })
+    }).collect();
+
+    for h in handles {
+        h.join().unwrap();
+    }
+    println!("philosophers dining end");
+}
\ No newline at end of file