diff --git a/ch5/user/src/bin/user_shell.rs b/ch5/user/src/bin/user_shell.rs
index e771f86..2dd5fec 100644
--- a/ch5/user/src/bin/user_shell.rs
+++ b/ch5/user/src/bin/user_shell.rs
@@ -11,7 +11,7 @@ const BS: u8 = 0x08u8;
 
 use alloc::string::String;
 use user_lib::{ print, println, waitpid};
-use user_lib::syscall::{sys_exec, sys_yield, sys_fork};
+use user_lib::syscall::{sys_exec, sys_yield, sys_fork, sys_get_time};
 use user_lib::user_console::getchar;
 
 
@@ -32,6 +32,8 @@ pub fn main() -> i32 {
                 println!("");
                 if !line.is_empty() {
                     line.push('\0');
+                    let mut st = sys_get_time();
+
                     let pid = sys_fork();
                     if pid == 0 {
                         // child process
@@ -46,7 +48,7 @@ pub fn main() -> i32 {
                         let mut exit_code: i32 = 0;
                         let exit_pid = waitpid(pid as usize, &mut exit_code);
                         assert_eq!(pid, exit_pid);
-                        println!("Shell: Process {} exited with code {}", pid, exit_code);
+                        println!("Shell: Process {} exited with code {}, use time: {}ms", pid, exit_code, sys_get_time()-st);
                     }
                     line.clear();
                 }