synchronization

问题 My following code got an error, when it runs, some of the graph weights are being overwritten, but that should not be happening with the Xa array(which keeps which ones have already been visited) and the __syncthreads() function... May someone help? struct Node { int begin; // begining of the substring int num; // size of the sub-string }; __global__ void BFS (Node *Va, int *Ea, bool *Fa, bool *Xa, int *Ca, bool *parada) { int tid = threadIdx.x; if (Fa[tid] == true && Xa[tid] == false) { Fa

问题 What is it? And what does it do? I'm working on an enterprise that has a proxy, and it fails trying to connect to somewhere. Why does it needs internet connection? What ports does it use? EDIT: The answer of the user Caleb was perfect. I would like to add that the proxy should be configured too in the gradle.properties. Something like this: systemProp.http.proxyHost=*proxyAddress* systemProp.http.proxyPort=*portNumber* systemProp.https.proxyHost=*proxyAddress* systemProp.https.proxyPort=

问题 sleep() is a static method of class Thread. How does it work when called from multiple threads. and how does it figure out the current thread of execution. ? or may be a more generic Question would be How are static methods called from different threads ? Won't there be any concurrency problems ? 回答1: how does it figure out the current thread of execution? It doesn't have to. It just calls the operating system, which always sleeps the thread that called it. 回答2: The sleep method sleeps the

问题 sleep() is a static method of class Thread. How does it work when called from multiple threads. and how does it figure out the current thread of execution. ? or may be a more generic Question would be How are static methods called from different threads ? Won't there be any concurrency problems ? 回答1: how does it figure out the current thread of execution? It doesn't have to. It just calls the operating system, which always sleeps the thread that called it. 回答2: The sleep method sleeps the

问题 I am a newbie to operating systems and every answer I've found on Stackoverflow is so complicated that I am unable to understand. Can someone provide an explanation for what is an atomic operation For a newbie? My understanding: My understanding is that atomic operation means it executes fully with no interruption ? Ie, it is a blocking operation with no scope of interruption? 回答1: Pretty much, yes. "Atom" comes from greek "atomos" = "uncuttable", and has been used in the sense "indivisible

问题 On a busy ASP .NET website, I have a Dictionary, which acts as a cache, basically storing key/value pairs for later retrieval. On high load, the Dictionary some times get into a state, where it always throws an IndexOutOfRangeException whenever i call the ContainsKey or Add method. The exception happens inside the private FindEntry method. I am suspecting that this might be due to a synchronization issue, but I am not sure. Can anyone tell me under which circumstances this can happen ? My

问题 I have a function that needs to be executed only when a callback is received from asynchronous function. Like I call asynchronous function Stop() and soon after that I call asynchronous function Start() . The Issue before Stop CallBack is received Start() is called and thus I am getting issues. Also I can not separate the calling of two functions Like I can not do this.: public void SomeFunction() { Stop(); } public void Stop_CallBack(eventargs e) { Start(); } I have to do this: public void

问题 Consider the following class: class Ideone { private Map<String, String> m; public Ideone(){ synchronized(this){ m = new ConcurrentHashMap<>(); } } public synchronized Map<String, String> getM(){ return Collections.unmodifiableMap(m); //effectively immutable } } In order to allow other classes to observe Ideone 's internal state, we should publish its internal state safely (with correct synchronization). If we don't do this, it's not guaranteed that another thread read the correct value (not

问题 So I've been working on program in which I'm creating a hash table in global memory. The code is completely functional (albeit slower) on a GTS250 which is a Compute 1.1 device. However, on a Compute 2.0 device (C2050 or C2070) the hash table is corrupt (data is incorrect and pointers are sometimes wrong). Basically the code works fine when only one block is utilized (both devices). However, when 2 or more blocks are used, it works only on the GTS250 and not on any Fermi devices. I understand

问题 I'm building a tab bar application for iPhone and i'm using Core Data with two UIManagedDocument s. In the first tab, i write the data to database and in the second i read them into UITableView with UIFetchedResultsController . At the start of application, if i write data first, and after then i read results, it works fine. Results appear in the second tab immediately. However, if i read some data first and after then if i write something to database, results appear in second tab with