los_tick.c

src/kernel_liteos_a/kernel/base/core/los_tick.c

@@ -37,30 +37,30 @@
 #endif
 
 
-LITE_OS_SEC_DATA_INIT UINT32 g_sysClock;
-LITE_OS_SEC_DATA_INIT UINT32 g_tickPerSecond;
-LITE_OS_SEC_BSS DOUBLE g_cycle2NsScale;
+LITE_OS_SEC_DATA_INIT UINT32 g_sysClock;    //系统时钟，绝大部分部件工作的时钟源，以及所有外设的始终来源
+LITE_OS_SEC_DATA_INIT UINT32 g_tickPerSecond;   //每秒Tick数，harmony默认为每秒100次即10ms
+LITE_OS_SEC_BSS DOUBLE g_cycle2NsScale;     //将周期转为纳秒级
 
 /* spinlock for task module */
-LITE_OS_SEC_BSS SPIN_LOCK_INIT(g_tickSpin);
+LITE_OS_SEC_BSS SPIN_LOCK_INIT(g_tickSpin);     //节拍器自旋锁
 
 /*
  * Description : Tick interruption handler
  */
-LITE_OS_SEC_TEXT VOID OsTickHandler(VOID)
+LITE_OS_SEC_TEXT VOID OsTickHandler(VOID)//节拍中断处理函数，harmony默认1ms触发一次
 {
 #ifdef LOSCFG_SCHED_TICK_DEBUG
     OsSchedDebugRecordData();
 #endif
 
 #ifdef LOSCFG_KERNEL_VDSO
-    OsVdsoTimevalUpdate();
+    OsVdsoTimevalUpdate();      //更新vdso数据页时间，vsdo可以直接在用户进程空间绕过系统调用获取系统时间
 #endif
 
 #ifdef LOSCFG_BASE_CORE_TICK_HW_TIME
     HalClockIrqClear(); /* diff from every platform */
 #endif
 
-    OsSchedTick();
+    OsSchedTick();//由时钟发起的调度
 }