synchronization

问题 Somebody can tell me an example of using locking mechanism based on futex? (for muticore x86 CPU, CentOS) 回答1: Pthreads' mutexes are implemented using futexes on recent versions of Linux. Pthreads is the standard C threading API on Linux, and is part of the Posix standard, so you can easily port your program to other Unix-like systems. You should avoid using futexes directly unless you have very unusual needs, because they're very hard to use correctly - use pthreads, or a higher-level,

问题 I followed this guide to implementing build numbers in an XCode iPhone project (guide). I tried it and I am getting the wrong build number when NSLogging. It's not updating correctly and is always one or two numbers behind the info.plist. I need it to be the same number. Anyone know why this is happening? i.e "[[[NSBundle mainBundle] infoDictionary] objectForKey:@"CFBuildNumber"]" is not the same as the plist's CFBuildNumber. The script is set to run first, before copy bundle resources and

问题 I am trying to figure an agreement protocol on an unreliable channel. Basically two parties (A and B) have to agree to do something, so it's the two generals' problem. Since there is no bullet-proof solution, I am trying to do this. A continuously sends a message with sequence 1 When B receives seq 1 it continuously replies with sequence 2 At this point A receives seq 2 so it starts sending seq 3 ... My question. When can the two parties conclude that they can take the action ? Obviously I

问题 This is actually a design question for firmware in an embedded system I have two ISRs (of same priority) executed independently . These ISRs are triggered when the h/w generates data. I want a mechanism which must be put in place to synchronise between task1 and task2. task 2 must know about the certain values calculated in task1 which must then be taken into account while computing certain values in task2. I don't have OS primitives to use ie the system does not have any Operating system.

问题 My problem is that I don't know how synchronise multiple threads using Ruby. The task is to create six threads and start them immediately. All of them should do some work (for example puts "Thread 1" Hi" ) one after another in the order I need it to work. I've tried to work with Mutex, Monitor and Condition Variable, but all of them worked in random order. Could anybody explain how to achieve my goal? After some time of struggling with Mutex and Condition Variable I've achieved my goal. This

问题 I have a python application that spawns a separate process to do some work (I ran into performance issues using threads due to the GIL (global interpreter lock)). Now what's my methods in python to synchronize shared resources across processes? I move data into a queue and a spawn process does the work when as it receives data from that queue. But I need to be able to guarantee that the data is coming out in an orderly fashion, same order as it was copied in so I need to guarantee that only

问题 When we call either lock.lock() or try to enter a synchronized block then our thread blocks if some other thread has already taken that lock. Now my question is, when we look at the implementation of lock.lock() it delegates acquiring lock to AQS which actually parks the current thread (so that it cannot be scheduled further by scheduler). Is it the same case with synchronized blocking also? I even think my thread status are also different. For example, if my thread is blocked on synchronized

问题 Closed . This question needs to be more focused. It is not currently accepting answers. Want to improve this question? Update the question so it focuses on one problem only by editing this post. Closed 7 days ago . I have just spent around five hours studying parts of the OpenGL 4.5 specification found here (or a slightly earlier version of it): https://www.khronos.org/registry/OpenGL/specs/gl/glspec45.core.pdf Unfortunately, I seem to be getting mixed messages. In section 5.3.1 “Determining

问题 Ive got a thread that does some work in the background and passes updates to the Form using the Invoke, BeginInvoke methods. The thread is created after the form is displayed so no issue there. The issue is how to correctly shutdown. My worker thread has the ability to be asked to exit, and will exit some time soon after that (miliseconds). However if the form has closed first the Invoke stuff breaks. I tried adding a Thread.Join to the forms closing event, but of course this causes a

问题 I'm trying to move some of my old projects from ThreadPool and standalone Thread to TPL Task , because it supports some very handy features, like continuations with Task.ContinueWith (and from C# 5 with async\await ), better cancellation, exception capturing, and so on. I'd love to use them in my project. However I already see potential problems, mostly with synchronization. I've written some code which shows a Producer / Consumer problem, using a classic stand-alone Thread : class