interrupt

I understand that a user can own a process and each process has an address space (which contains valid memory locations, this process can reference). I know that a process can call a system call and pass parameters to it, just like any other library function. This seems to suggest that all system calls are in a process address space by sharing memory, etc. But perhaps, this is only an illusion created by the fact that in high level programming language, system calls look like any other function, when a process calls it. But, now let me take a step deeper and analyze more closely on what

This question already has an answer here: What does java.lang.Thread.interrupt() do? 9 answers I am not clear regarding these two methods from the perspective of setting the status of the thread. Java Docs say that Thread.interrupt() sets the threads interrupt status flag and calling the Thread.interrupted() method gives the status of the thread and clears the flag. When this comes to use in real scenarios..?? When some other thread calls Thread.interrupt() the method sets Thread's interrupt status flag (initially false) to true. If the Thread is in blocking method like Thread.sleep(), Thread

Java SE7 API - Thread: http://docs.oracle.com/javase/7/docs/api/java/lang/Thread.html#yield%28%29 参考资料： http://blog.csdn.net/lqqmisslll/article/details/54208491 一、线程的简介 当JVM启动的时候， 通常会有一个独立的非守护线程（也就是类中的main方法所在的线程）.JVM会继续运行，除非发生以下情况： Runtime类的exit()方法被调用，并且安全管理者允许退出发生。 所有非守护线程都已经死了，不管是从run方法中返回的还是因为run方法中抛出了异常。 注意：当所有非守护线程都执行结束（包括主线程），那么守护线程也会退出。因为守护线程是无法脱离非守护线程而独自存在的。 二、创建线程有两种方式： 方法1：声明一个类作为Thread的子类（extends Thread），子类重写（override）Thread类的run()方法。子类的实例可以被分配和start。 //比如：该线程用来计算比指定起始值大的素数。 class PrimeThread extends Thread { long minPrime; PrimeThread(long minPrime) { this.minPrime = minPrime; }

I was studying about interrupts. So most architecture are interrupt driven, if everything is interrupt driven, how fast the processor can handle all of those. For example, while pressing a key board keys, it creates an interrupt asking the kernel to look for the buffer for new characters, in that case, how fast the processor can serve, also when an interrupt is put, the processor needs to switch to kernel space and that costs a lot in terms of context switch. So I assume, even after all these if the processor has a good performance, then I can only assume that the time between two key strokes

Is volatile needed for a variable that is read&write in main loop, but read-only in ISR? EDIT: At the moment of writing in main, the ISR is disabled. So, the variable is effectively used atomically. EDIT: (Very much related): volatile vs memory barrier for interrupts volatile is a bad way to synchronize access. It is an optimization barrier but not more. it is not atomic; e.g. when your some_type is uint64_t on a platform without native 64 bit datatypes, there might be read only a part. E.g. main() irq() /* initialization */ var[0..31] = 4 var[32..63] = 8 /* modificatoin */ var[32..63] = 23 /*

For example, a key on a keyboard is press causing a hardware interrupt to be generated to the CPU, the CPU sends an acknowledgement to the interrupt controller. At the stage of the interrupt process, how does the CPU knows which interrupt service routine to run based on a key press on the keyboard? 来源： https://stackoverflow.com/questions/48110019/how-does-the-cpu-knows-which-interrupt-service-routine-to-run-against-a-hardware