multithreading

问题 I have been studying multithreading in python for a while, however I was confused on a few issues- Firstly, are the threads created by the python threading library user level or kernel level threads? Books say that user level threads must be mapped to kernel threads and the operating system only creates and maintains kernel level threads. Which thread model will be used in the python threading library? Further, who makes the choice between kernel and user level threads? Is it the operating

问题 I have been studying multithreading in python for a while, however I was confused on a few issues- Firstly, are the threads created by the python threading library user level or kernel level threads? Books say that user level threads must be mapped to kernel threads and the operating system only creates and maintains kernel level threads. Which thread model will be used in the python threading library? Further, who makes the choice between kernel and user level threads? Is it the operating

问题 Normally, I would assume that C++ 11 thread automatically destroy after detach. But the thing is, I can't find anything to prove this assumption. According to this article Once detached, the thread should live that way forever. forever? If the function of the thread finish, Does its resource remain forever? According to this article After a call to this function, the thread object becomes non-joinable and can be destroyed safely. It can be destroyed safely, but is it automatically? If it's

问题 I'm currently trying to understand this JLS section on final fields. To understand the text in the JLS better I'm also reading The Java Memory Model by Jeremy Manson (one of creators of the JMM). The paper contains the example that got me interested: if an object o with final fields is made visible to another thread t twice: first "improperly" before o 's constructor finishes next "properly" after o 's constructor finishes then t can see semi-constructed o even when it is accessed only via a

问题 Assume we have a struct capable of self-mutation that has to happen as part of a background operation: struct Thing { var something = 0 mutating func operation(block: () -> Void) { // Start some background operation dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0)) { // Mutate self upon background task completion self.something += 1 block() } } } Now, when I use such a struct in context: var myThing = Thing() myThing.operation { println(myThing.something) } The

问题 Assume we have a struct capable of self-mutation that has to happen as part of a background operation: struct Thing { var something = 0 mutating func operation(block: () -> Void) { // Start some background operation dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0)) { // Mutate self upon background task completion self.something += 1 block() } } } Now, when I use such a struct in context: var myThing = Thing() myThing.operation { println(myThing.something) } The

问题 Assume we have a struct capable of self-mutation that has to happen as part of a background operation: struct Thing { var something = 0 mutating func operation(block: () -> Void) { // Start some background operation dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0)) { // Mutate self upon background task completion self.something += 1 block() } } } Now, when I use such a struct in context: var myThing = Thing() myThing.operation { println(myThing.something) } The

问题 I have a list that contains roughly 200K elements. Am I able to pass the iterator for this list to multiple threads and have them iterate over the whole lot, without any of them accessing the same elements? This is what I am thinking of at the moment. Main: public static void main(String[] args) { // Imagine this list has the 200,000 elements. ArrayList<Integer> list = new ArrayList<Integer>(); // Get the iterator for the list. Iterator<Integer> i = list.iterator(); // Create MyThread,

问题 I have a list that contains roughly 200K elements. Am I able to pass the iterator for this list to multiple threads and have them iterate over the whole lot, without any of them accessing the same elements? This is what I am thinking of at the moment. Main: public static void main(String[] args) { // Imagine this list has the 200,000 elements. ArrayList<Integer> list = new ArrayList<Integer>(); // Get the iterator for the list. Iterator<Integer> i = list.iterator(); // Create MyThread,

问题 I have this pretty straightforward piece of code that very rarely throws "System.ApplicationException : Object synchronization method was called from an unsynchronized block of code." when ReleaseMutex () is called. I logically analyzed the flow of the method and just cannot understand how/why this could happen. To my understanding, the ownership of mutex is guaranteed in this case: readonly string mutexKey; public Logger(string dbServer, string dbName) { this.mutexKey = ServiceManagerHelper