// 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)
函数签名如上：目前理解的是这组函数可以实现groutine排队等待的阻塞以及唤醒的通知。但是不理解这个追踪期间忽略的帧数是什么含义？如果设置10和设置0有什么区别吗。