Multi-threading related questions including technique, structure, and safety issues.

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Pass Event between Systems in a multi-threaded Entity-Component-System [closed]

To clearify my question: Is there a way to pass Events between Systems in a multi-threaded Entity-Component-System? Original Post: I've read a german article about the Entity-Component-System ...
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1answer
36 views

How to effectively split jobs into groups for multiprocessing when the job sizes are unknown

With K processor cores, how to optimally split N jobs into groups, with each group to be processed sequentially by one processor core, when the time to process each job is unknown ahead of time and ...
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2answers
164 views

When is lock not needed in multithreading

I want 500 objects to be processed concurrently using multithreading. These objects will have some initial data before the threads are created. I am creating 5 threads and each thread takes 100 ...
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0answers
13 views

Android, using a Fragment to hold/edit complex object, accesible from any Activity

I'll do my best to describe the problem, but I'm still very new to several concepts that I think this problem requires to be solved (namely interfaces and threads). I should preface this by saying ...
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1answer
79 views

Is this an spurious wakeup or just a funky (non-spurious) race condition?

According to wikipedia: "The race conditions that cause spurious wakeups should be considered rare". But when I run this code, it is showing me that spurious wakeup happens quite often. Is this ...
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3answers
210 views

Implementation strategies for atomic counter

I basically have a counter variable that is decremented and frequently polled. There are three options to implement that, that I can think of: Number 1: private volatile int count; public void ...
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0answers
28 views

how to remove threads in vector list container in java [closed]

Enumeration e = v1.elements(); while(e.hasMoreElements()){ Serverthread stm = (Serverthread)e.nextElement(); stm.send(str); } Enumeration ex=names.elements(); int ...
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2answers
160 views

MVC pattern synchronisation

I am facing a problem in synchronizing my model and view threads I have a view which is table. In it, user can select a few rows. I update the view as soon as the user clicks on any row since I don't ...
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0answers
54 views

Using Singletons in JS with workers

I'm building a javascript application that does continuous drawing, but relies on asynchronous scripts in the background which also need to poll for events and write to "global variables". This got me ...
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1answer
66 views

Should CountDownLatch be used for waiting for an event?

I have a situation here, where I have a loop that loops x amount of times. The value x is determined by the user. Everytime it loops, I want it to wait for a button click before continuing the loop. ...
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4answers
491 views

Why aren't we building and using parallel processors *meant* for general computation?

We all know GPUs are much faster than CPUs for a wide range of applications. When someone asks why we are not just programming for GPUs at all, one of the most common answers is that GPUs are not good ...
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2answers
168 views

Are there alternatives to using an optional type in a multithreaded environment?

I'm making an MPMC queue in C++, and I would like to find out what the best interface for a try_dequeue method would be (I'm not concerned about its implementation). I'd like to provide a method which ...
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1answer
119 views

Multithreaded Pre/Post Functions

I'm programming an application for an embedded device. We are using an RTOS that supports multi threading. The device is supposed to mimic an older project that was programmed in plain C (without ...
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5answers
3k views

Testing multi-threaded race conditions

Reading the comments to this answer, specifically: Just because you can't write a test doesn't mean it's not broken. Undefined behaviour which usually happens to work as expected (C and C++ are ...
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3answers
127 views

How should be the approach to start thinking about multi thread programming [closed]

I am an experienced java developer.Of now I have started learning multithreading in java.I am able to grasp most of the concepts but still I am unable to visualize applications running on threads.I ...
4
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1answer
131 views

Error Handling Strategies in Multithreaded Environments

TL;DR What error generating and handling strategies do you use in Multithreaded code intended for use by others and why do you use them? If applicable, state what programming paradigm it's useful for. ...
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6answers
4k views

Multithreading: am I doing it wrong?

I'm working on an application that plays music. During playback, often things need to happen on separate threads because they need to happen simultaneously. For example, the notes of a chord need to ...
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3answers
808 views

What are the so-called “levels” of understanding multithreading?

I seem to remember reading somewhere some list of 4 "levels" of understanding multithreading. This may have been in a formal publication, or it may have been in an extremely informal context (even ...
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2answers
61 views

UI Applications and operations in background threads

I am not really sure about what is the best way to deal with operations executed in background threads in an application I am writing. I am writing it in C# and I am following the MVVM design ...
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1answer
72 views

Synchronized access to network industrial equipment

I have an industrial equipment which is controlled by a software. The software connects to it using sockets, and keeps the connection all the time alive, while from time to time sending commands to ...
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1answer
268 views

Do threads delete themselves?

Let's say I was working on a Swing application. Most of it is run on the EDT using SwingUtilities.invokeLater() inside the main method, because I heard (please correct me if I'm wrong) that that's ...
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1answer
1k views

Is there a difference between fibers, coroutines and green threads and if that is so what is it?

Today I was reading several articles on the Internet about fibers, coroutines and green threads, and it seems like these concepts have very much in common, but there are slight differences, especially ...
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2answers
45 views

Should I reference a CopyOnWriteArraySet from the Set interface?

There are two ways to use a CopyOnWriteArraySet: // A Set<Object> set = new CopyOnWriteArraySet<>(); and // B CopyOnWriteArraySet<Object> set = new CopyOnWriteArraySet<>(); ...
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1answer
178 views

How can I set a time limit for a game?

I am learning the multi-threading and timer in C# now. But it seems I can't find a good solution. For example, I would like to see how many addition problems that I can solve within 1 min. I would ...
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0answers
135 views

Scheduling a few CPU-intensive tasks

I need to schedule a small number of CPU-intensive tasks to run every so often, reading from shared data and writing to dedicated buffers. I don't necessarily want to roll my own scheduling, but am ...
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2answers
576 views

Can someone explain in simple terms what is the disruptor pattern?

I would like if you could explain to me in a simple way how does the disruptor patter work. This concept has been elusive to me as of know. Perhaps with your help I could comprehend it.
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1answer
155 views

Why (most?) retro computer emulators are single threaded?

All real computer hardware works in parallel. So why most emulators of retro systems (like NES) are single threaded (or I'm not right?)? You have main loop and you counting CPU cycles and after ...
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1answer
132 views

Good approach for hundreds of comsumers and big files

I have several files (nearly 1GB each) with data. Data is a string line. I need to process each of these files with several hundreds of consumers. Each of these consumers does some processing that ...
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4answers
440 views

When creating a library for a simple program, what must I do to protect others from its lack of thread safety?

When creating a library for a simple program, is it more cost effective to make it thread safe or is there a way to detect the program's use in a multithreaded program and ASSERT() or otherwise ...
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3answers
235 views

Is it safe to rely on static analysis to “reproduce” concurrency bugs reliably?

I've inherited some Java code which I suspect harbours some concurrency bugs when synchronizing between a thread that queries data and an IO event that updates the same data. I'm trialling a static ...
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0answers
28 views

API providing function to be run in a thread vs. thread that runs this function

I'm writing a Python library which exposes a certain event listener interface. The user can register callbacks to handle different types of events. There is also a function which handles the actual ...
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4answers
2k views

What prevents a race condition on a lock?

I understand the basics of what data races are, and how locks/mutexes/semaphores help prevent them. But what happens if you have a "race condition" on the lock itself? For example, two different ...
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0answers
37 views

Why is sem_post pthread_mutex_lock protected while sem_wait is not?

All the pthread semaphore examples I have seen protect the sem_post call with a pthread_mutex_lock, but the sem_wait is left unprotected! It seems to me that sem_wait also should be protected in some ...
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3answers
112 views

In which object should I implement wait()/notify()?

I'm working in an Android project with multithreading. Basically I have to wait to the server to respond before sending more data. The data sending task is delimited by the flag boolean ...
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0answers
108 views

How can I make a universal construction more efficient?

A "universal construction" is a wrapper class for a sequential object that enables it to be linearized (a strong consistency condition for concurrent objects). For instance, here's an adapted ...
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3answers
255 views

What is Atomicity?

I'm really struggling to find a concrete, easy to grasp, explanation of Atomicity. My understanding thus far is that to ensure an operation is atomic you wrap the critical code in a locker. But ...
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1answer
546 views

Relationship between “Task Parallel Library” and “Task-based Asynchronous Pattern”?

In the context of C#, .NET 4/4.5 used for an application running on a web-server, what is the relationship between "Task Parallel Library" and "Task-based Asynchronous Pattern"? I understand one is ...
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2answers
97 views

When one thread out of four is executing first line in run() then at the same time what will remaining three threads do?

I have four thread instances and they are executing run() code given below: public void run (){ System.out.println("1st line :"+Thread.CurrentThread().getName()); System.out.println("2nd line ...
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2answers
156 views

How other thread can show the incremented value unless the 1st thread reaches the return statement?

My code is given below. In the for loop I am getting unexpected output i.e. before completing the execution of for loop by 1st thread the 2nd thread comes in for loop and shows incremented value. ...
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1answer
425 views

When should I use ZeroMQ and when should I use Akka?

My understanding of Akka is that it allows you to define groups of mini-threads ("Actors") and then have them communicate with each other (and do work) using events. My understanding of ZeroMQ is ...
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1answer
352 views

WCF service - best way to accept requests from a client and do background work?

For a project at work, I was tasked to create a WCF service that will receive email messages from client and queue them on a database, while at the same time the service will check the DB every 30 ...
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1answer
154 views

Can the possibility of a data race be ignored in some cases? (while having concurrent threads) [duplicate]

I am programming a game engine as a hobby project, and I would like to separate physics and drawing into two separate threads. The position vectors of entities are subject to modifications by the ...
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3answers
4k views

Why not Green Threads?

Whilst I know questions on this have been covered already (e.g. http://stackoverflow.com/questions/5713142/green-threads-vs-non-green-threads), I don't feel like I've got a satisfactory answer. The ...
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1answer
714 views

What's the current best practice for C multithreading?

I've been a Java (and PHP) developer for most of my life, but will need to use C for my next project. I remember some basic stuff we did back in school with fork, pthread, semaphores, etc. but I'm not ...
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0answers
63 views

Primes and multi-threading

I use to compute primes using linear code which took a long time. As I've an 8 cores processor I thought about multi-threading. At first I use to put a huge number of int in a vector then share the ...
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4answers
930 views

Should multi-threading be used for tasks which does not involve IO operation?

I was reading a book on OS and got confused between different terminologies. I hope i will get my doubt cleared here. These questions might be very basic for some experts, but i find this platform ...
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1answer
136 views

Using a progress dialog and multi threading

My .NET Windows desktop application creates an HTML report, and has 3 main phases. It may create multiple reports. I show a progress bar so the user knows (estimates) how long it will take (as well ...
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346 views

Make a java program use more processors

I am running a program that is supposed to solve a problem with the brute force approach. My computer has a quad-core CPU. When I run the program clearly java uses only one core, because in my ...
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5answers
2k views

Does immutability entirely eliminate the need for locks in multi-processor programming?

Part 1 Clearly Immutability minimizes the need for locks in multi-processor programming, but does it eliminate that need, or are there instances where immutability alone is not enough? It seems to ...
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1answer
107 views

Use of separate threads or singe thread

In my project, on a security system, I was using a socket to get the details of the client and then store it in a database (his IP and port he connected from and service he accessed). I was wondering ...