diff --git a/AppKit/stopwatch.c b/AppKit/stopwatch.c
new file mode 100644
index 0000000..137f10e
--- /dev/null
+++ b/AppKit/stopwatch.c
@@ -0,0 +1 @@
+#include <stopwatch.h>
diff --git a/AppKit/stopwatch.h b/AppKit/stopwatch.h
new file mode 100644
index 0000000..122836d
--- /dev/null
+++ b/AppKit/stopwatch.h
@@ -0,0 +1,38 @@
+#ifndef INCLUDED_STOPWATCH_H
+#define INCLUDED_STOPWATCH_H
+
+#ifndef INCLUDED_OS_SYSTICK_H
+#include <os_systick.h>
+#endif /*INCLUDED_OS_SYSTICK_H*/
+
+
+/* ------------------------------------------------------------------------------------------------------------------ */
+/*  */
+
+typedef struct {
+    volatile os_tick_t start_tick;
+    volatile os_tick_t end_tick;
+}stopwatch_t;
+
+OS_STATIC_FORCE_INLINE
+void stopwatch_init(stopwatch_t* self) {
+    self->start_tick = os_systick_safe_get();
+}
+
+OS_STATIC_FORCE_INLINE
+void stopwatch_start(stopwatch_t* self) {
+    self->start_tick = os_systick_safe_get();
+}
+
+OS_STATIC_FORCE_INLINE
+void stopwatch_stop(stopwatch_t* self) {
+    self->end_tick = os_systick_safe_get();
+}
+
+OS_STATIC_FORCE_INLINE
+os_tick_t stopwatch_elapsed_ticks(stopwatch_t* self) {
+    return self->end_tick - self->start_tick;
+}
+
+
+#endif /*INCLUDED_STOPWATCH_H*/
diff --git a/Kernel/SingleCore/os_systick.h b/Kernel/SingleCore/os_systick.h
index 60e6af3..f8f4a4b 100644
--- a/Kernel/SingleCore/os_systick.h
+++ b/Kernel/SingleCore/os_systick.h
@@ -69,15 +69,23 @@ void os_systick_tick(void){
 
 OS_STATIC_FORCE_INLINE
 os_tick_t os_systick_get(void){
-#if 0
-    os_critical_enter();
-    os_tick_t ticks =  g_os_systick_ticks;
-    os_critical_leave();
-    return ticks;
-#endif
     return g_os_systick_ticks;
 }
 
+OS_STATIC_FORCE_INLINE
+os_tick_t os_systick_safe_get(void) {
+    os_critical_enter();
+    const os_tick_t ticks =  g_os_systick_ticks;
+    os_critical_leave();
+    return ticks;
+}
 
+OS_STATIC_FORCE_INLINE
+os_tick_t os_systick_safe_get_in_isr(void) {
+    os_critical_enter_in_isr();
+    const os_tick_t ticks =  g_os_systick_ticks;
+    os_critical_leave_in_isr();
+    return ticks;
+}
 
 #endif /*INCLUDED_OS_SYSTICK_H*/