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

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Difference between TSimpleRWSync's BeginWrite and BeginRead methods?

I have recently switched to TSimpleRWSync from TRTLCriticalSection. The methods BeginRead and BeginWrite confuse me as wherever I read help, they seemingly do the same thing i.e. acquire the critical ...
17
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4answers
3k views

Programs that claim they are not “multi-core” friendly

You see this phrase or similar kicked around from time to time, generally referring to a program that claims they were not designed to take full advantage of multi-core processors. This is common ...
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0answers
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Threading and async intterupting on same process and thread, along with related

So, I'm trying to understand threads. I realize they are a mix of hardware and OS decisions. I also know that a thread, or process, has a set of register/stack variables and functions. In each thread, ...
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1answer
514 views

Running a process multiple times at the same time

I have a c++ program with opencv library which takes an image as input and perform pose estimation,color detection,phog. When I run this program from the command line it takes around 4-5sec to ...
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3answers
192 views

Is it possible to perform mutual exclusion of threads without OS support?

I suppose you could adapt distributed mutual exclusion algorithms (Ricart/Agrawala, etc), but aside from these more exotic approaches, are you required to use primitives provided by the OS in order to ...
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1answer
112 views

Non-Recursive vs Recursive Locks?

I am thinking of using non-recursive locks; I have found them to be having performance superiority over the standard recursive locks (e.g. SimpleRWSync). I have mainly been using critical sections but ...
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0answers
172 views

Managing child worker thread list

After so much research, I thought I should ask the experts. I am working on a project for my corporate employer, we have android and iPhone mobile apps that make request to a web service, the request ...
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2answers
151 views

Emulating communication between Android and microcontroller using threads or services or… other?

I am not sure what is the best way for the tasks below: threads, AsyncTasks, Loopers, services? Why? Are there other candidates? I need threads/Tasks/Services/other for: Plotting data, (refreshing ...
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1answer
221 views

Extracting data from log files

I will be extracting certain bits from log files using regular expressions to filter out bit of data. Initially I was going to do this with Python. I later started to think about the fastest way I can ...
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0answers
497 views

Best method for async initialization of view model in MVVM pattern (WPF)

I'm working on a business application (C#, WPF, EF, MVVM). I need to load a bunch of items from database, create view models for them and put them in a window. Is there a way to create the view model ...
8
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1answer
2k views

Are go-langs goroutine pools just green threads?

The commentator here offers the following criticism of green threads: I was initially sold on the N:M model as a means of having event driven programming without the callback hell. You can write ...
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0answers
102 views

Why user threads are mapped to Kernel threads

Since user threads are mapped to kernel threads, why don't we create all threads as kernel threads that is a process with zero user thread. Doesn't mapping of user thread to kernel thread create ...
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1answer
1k views

Database design/relationship for threading messages

What's the database design or business logic for creating an app for messaging between users? I am having difficulties with choosing how to approach the relationship between each Conversation of User ...
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2answers
1k views

How Stack and Heap is allocated for threads under the same process in Windows?

Stack for different thread is different.but what about Heap. If Heap is different for different threads, then how they share objects?
2
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1answer
223 views

Transactional Memory vs Mutex and Locks

Just found out that Intel processors now have Transactional Memory support !!!! I learned about Transactional operations in my dB/OS class, it is a very simple concept: entire operation is executed or ...
14
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1answer
765 views

How can I tell if I am overusing multi-threading?

I currently feel like I am over-using multi-threading. I have 3 types of data, A, B and C. Each A can be converted to multiple Bs and each B can be converted to multiple Cs. I am only interested in ...
1
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1answer
127 views

Optimising news fetching

I have a web scraper for scraping news from different sources in wp7. My current appraoch for doing this is: load newspapers information from xml file. go to the specified sections and fetch the ...
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2answers
175 views

Why would Java app make RPC call to itself?

I am working with a multithreaded homegrown multi-module app in my new job. We use the the Thrift protocol to communicate RPC calls between different stand-alone applications in a distributed system. ...
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0answers
115 views

Alternatives to Pessimistic Locking in Cluster Applications

I am researching alternatives to database-level pessimistic locking to achieve transaction isolation in a cluster of Java applications going against the same database. Synchronizing concurrent access ...
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3answers
209 views

How do I limit the resources available to a program?

I'm delving into multi-threaded programming with Java, but I'm finding it hard to test my program for bugs. My computer simply has too many resources and cores, making it hard to see how my program ...
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0answers
440 views

Java UDP Multithread Server

I have multiple threads. Each thread receives data and sends to client an acknowledge packet. Each thread takes aprox. 531ms from start to finish. While capturing packets with wireshark. I was ...
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1answer
690 views

C# Design for SQL connection and commands

Currently I'm working on system that works with database, and I would like to have it done elegant way. So I have abstracted DBConnection into one class, DBCommands into another class. (DBCommands : ...
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1answer
867 views

c++ web with nginx - Do I have to worry about thread safety?

I am currently developing my website with c++. I know that nginx handles connections with multiple threads to provide high performance. And not all c++ code is thread safe. What's the relationship ...
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1answer
124 views

Do you have to ban atomics to get good tool support for race detectors?

It seems that Helgrind treats atomics the same way as normal read/write operations. So, using atomics will result in lots of false positives. I don't know exactly how ThreadSanitizer deals with ...
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1answer
2k views

Sleeping Barber Problem (with multiple barbers)

The Sleeping Barber Problem is a classical synchronization problem that many of you may be familiar with or at least heard of. It's based on the premise that a barber (a thread) sleeps when there ...
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2answers
602 views

Memory allocation of Classes that don't have any global data and locks

static void Main(string[] args) { var c2 = new Class2(); var c3 = new Class3(); var c1 = new Class1(c2, c3); c1.Method1(); } class Class1 { ...
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2answers
203 views

When will be safe to choose Multi-thread design without dead lock? [closed]

Sometime we really need to choose a multi-threaded design, because single-threading will block the UI or block another thread. But sometimes using multiple threads is just one of the choices, for ...
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2answers
213 views

What are the different aspects to consider when porting code from a single threaded environment to a multi threaded environment or vice versa?

I want to provide some library functionality and a reference application, which will run on a fully-featured, POSIX-compliant platform. The app and library will need bi-directional serial port ...
3
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1answer
105 views

Are mutexes assigned to specific regions of memory?

I'm currently reading C++ Concurrency in Action by Anthony Williams and I'm facing an obstacle in thought. First he describes deadlocks as when two threads lock simultaneously (at least, that's how I ...
4
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1answer
656 views

Design patterns for multi-threaded messaging server

I'm designing an instant messaging server as a personal exercise to improve my understanding and application of multi-threading and design patterns in Java. I'm still designing, there's no code yet. ...
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1answer
378 views

Python multithreading and utilizing modern processors - what is the downside?

CPython implementation detail: In CPython, due to the Global Interpreter Lock, only one thread can execute Python code at once (even though certain performance-oriented libraries might overcome ...
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2answers
130 views

Listener, logger, plotter - what threading arcitecture to choose for this?

I am constructing a program that does several things. Listens to a port. Every second a string is received When new data is received, it has to be logged. No errors or skipped entries are allowed ...
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5answers
375 views

What are some good assignments for an introductory course on concurrent programming? [closed]

I am teaching a course which involves introducing the students to the concept of threads and concurrent programming. I am in search of programming assignments that can gently get them to accept the ...
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2answers
235 views

How do I get rid of cyclic references in this design?

I have 3 classes: Meeting, Project and Agenda. A Project contains all sort of information + a list of meetings. The Agenda contains a list of upcoming Meetings. A Meeting contains some data + a list ...
2
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1answer
216 views

Multi-Thread Return Single SQL Result

I am having some difficulty with MySQL and returning a unique row to a thread. I want it so the thread will search for a row from the table where the bit (see below) is false and only one row is ...
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1answer
188 views

How do I find a good middle way to make this library safe for concurrent operations

I've made a little library called SignalR.EventAggregatorProxy Before I push it into 1.0 state I need to fix so it works safely with concurrent operations. Easiest way is lock all operations but ...
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1answer
600 views

Which child process will inherit threads of parent process?

What happens when one process have child threads and child process , will child process inherit all child threads of parent process.? Assume OS is Linux . Let it be Java Threading model.
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4answers
963 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
1k views

How to make a method synchronized across all instances of an object

Today I was asked this interview question and could not answer. : If you have two instances of a Person Object and each of them have a setAddres method that is synchronized. Now if it was only one ...
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3answers
1k views

How many threads should access the file system at the same time?

We have a module in an application which stores data in multiple files and multilevel directories and access them from multiple threads (both reads and writes). The directory structure is based on a ...
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2answers
740 views

Uses of persistent data structures in non-functional languages

Languages that are purely functional or near-purely functional benefit from persistent data structures because they are immutable and fit well with the stateless style of functional programming. But ...
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1answer
219 views

What operating systems use both a Render thread and a UI thread?

Microsoft employees commonly describe Windows 8 as having both a Render thread and UI thread. Typically they say the Render thread performs animations and the UI thread handles most other operations: ...
6
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2answers
5k views

How is multi-threading different in a Java based Web Application vs Stand-alone Java Application

I am fairly new to Java and my experience is limited to Web Based Applications running on a Web Container (Jboss in my case). Am I correct in saying that for Web Applications the web container takes ...
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1answer
2k views

High-Load Java Server for Multiplayer

I am making a multiplayer game. Now I am trying to choose the technology to connect the android devices to the server. The clients run on Android, and the game is MMORPG. I would like to write the ...
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2answers
136 views

Loading chunks around center

I am making a voxel game like Minecraft. I am able to load chunks using multithreading with the code... for (int x = 0; x < WorldSettings.WORLD_WIDTH_IN_CHUNKS; x++) { for (int y = 0; y < ...
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1answer
241 views

Is there a time bomb in sequential process id allocation when the `unsigned` wraps?

I'm designing and implementing a multiprocessing postscript interpreter ("lightweight" processes simulated by a single OS-thread), and I need to generate a unique identifier for each process in the ...
6
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4answers
738 views

Is it a performance hit to create threads that loop a lot to check for things?

This is a generic question that I've always wondered. In general, is it intensive for a CPU to create threads that perform "while not true ..." loops or similar? For example, suppose I do: // ...
8
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2answers
750 views

Would Task-based programming in C++ require new language standard features?

So I saw this video on Youtube with all these C++ masters on GoingNative 2012 : Interactive panel where everybody could ask the questions. This is the video I was talking about: GoingNative 2012 - ...
6
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4answers
2k views

Threads or ThreadPool? Fixed or Dynamic ThreadPool?

I have a java program which listens on a port for input. Based on Input, it calls a webservice and then returns a success/failure back to the client program. I fork a thread for each client ...
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2answers
470 views

Multi-Threaded JavaScript?

I know, I know--it isn't possible presently BUT my question is this: Would it be possible to write a browser plug in for the major browsers that enables true, multi-threaded JavaScript? It just ...