關於 groutine 喚醒中 skipframes 引數不理解

// SemacquireMutex is like Semacquire, but for profiling contended Mutexes.
// If lifo is true, queue waiter at the head of wait queue.
// skipframes is the number of frames to omit during tracing, counting from
// runtime_SemacquireMutex's caller.
func runtime_SemacquireMutex(s *uint32, lifo bool, skipframes int)

這個 skipframes 代表的是什麼意思？ go1.14 在 RWMutex 的邏輯中只有 Runlock 時為 1，其他時候都是 0 是什麼原理？