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Questions tagged [multithreading]

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Multi-threading is how work performed by a computer can be divided into multiple concurrent streams of execution (generally referred to as threads).

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125 views

Ultra fast Amazon scraper multi-threaded

This is a follow up to the code here: Web scraper that extracts urls from Amazon and eBay A multi-threaded modification to the previous version that is Amazon focused and most of the necessary ...
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1answer
34 views

Finding similar items in two arrays with multithreading in C++

I'm exploring multithreading for some code that I want to speed up in C++. I wrote a simple program to facilitate my understanding. The program takes in two arrays of equal length, the value of the ...
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ReentrantLock.signal() not working as expected but ReentrantLock.signalAll() works. Why? [closed]

In my simple code below, if I replace condition1.signal()/condition2.signal() with ...
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0answers
31 views

Find parallel-base left-truncatable primes

Factorial base - representation of numbers not as sums of base_number^digit_number, but as sums of digit_number! (factorial). So 7 (decimal) is represented as 101_! in factorial base, because 7 = 6+1 =...
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Thread await and execute different methods based on some event or value

Use case: I am writing a proactive session updater; The use case is for parallel API calls or sequential API calls intercept the API call and check whether token is valid. If token is valid ...
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2answers
313 views

Self-inflicted killing utility

If you need to kill the same process that you're in (for testing purposes or whatever) this code will do it. A definitive, quick, unmerciful dead of the current Java program/app. Not a System.exit(0) ...
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60 views

Unisex Bathroom problem with semaphore

An office has a bathroom that can be used by both men and women, but not both at the same time. If a man is in the bathroom, other men may enter, but any women wishing to use the bathroom should wait ...
4
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2answers
101 views

Swift main thread style

I run into issues where I forget to run UI changes on the main thread. I've just fixed an issue for loading and unloading an activity indicator and fixed it with the following code: ...
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1answer
433 views

C++ Standard-Thread Threadpool

I have written a small and simple ThreadPool class for rather simple multithreading applications. The Threadpool class manages ...
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2answers
968 views

Implementation of a Thread Pool in C++

I wanted to implement a thread pool to test my knowledge of various modern C++ features. The end result could be better, but I need a review as I'm not sure about delicate things especially regarding ...
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32 views

Setting Timeout For Scheduled Task In Java

I am trying to set timeout for tasks which executed by scheduler in Java. I managed to write necessary codes, they are working well but I guess something is not right. I have scheduler's thread pool ...
4
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1answer
56 views

A thread that can be interrupted before starting

As per the Java documentation: Interrupting a thread that is not alive need not have any effect. Particularly, interrupting a thread between the call to start() and the invocation of run() has no ...
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3answers
123 views

Effective fetching data algorithm

I'm fetching some data by using bs4, and want to know why access speed gets slower as my program progresses. I'm using thread, and I know threading isn't so fast because of GIL. My problem is that ...
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1answer
102 views

Modelling a Call Center in Java (multithreading approach)

I wanted to give a shot to Modelling a Call Center from Cracking the Coding Interview. The problem statement is as follows: You have a call center with three levels of employees: Respondent, ...
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1answer
30 views

Using a thread to update a table automatically in Django

For my portfolio app using Django I made a thread that pulls out the usd exchange rates for various currencies every 6 hours and updates the database. The program kicks in as soon as the module ...
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3answers
356 views

Process queued data in the background

Currently I'm writing something like a messaging or logging framework (I'm not really sure how you name something like that). There are different servers which have to be notified if something happens....
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2answers
242 views

Action queue manager to perform action in a FIFO fashion

Recently, I needed a class that could execute code in a FIFO fashion in order to update parts of a WinForms or WPF UI which did not block the UI Thread and left the UI responsive to any interaction ...
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2answers
61 views

TaskScheduler in python

I have found the need to schedule a few simple functions in a first-come-first-served way so I developed a small task scheduler based on multiprocessing and I thought it would be a good candidate for ...
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0answers
52 views

Fast text search in Rust

I have a large file that I want to search for text as fast as possible. There is not a memory contraint, so I am loading the entire file into memory so that I can use the rayon parallelism crate in ...
5
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2answers
179 views

Process multiple request from different threads in batches on one processing thread

So I have a system that uses multiple threads to process data. These data could be processed individually but it would be better to process them in batches. Lets assume we have a class ...
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1answer
59 views

Multithreading to process requests and save results in python

I was presented with a task to come up with a script that generates a CSV with POSTAL codes via bruteforce (I'm in Brazil, so that means CEP to us). Points to note: I'm using an external library, ...
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Motor control PLC in Python

Project description We have different types of devices like sov, motor, analog, digital, control valves etc. Each type of device has 100 items. Now our software continuously monitors with the PLC to ...
7
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2answers
135 views

Python-style Generator in Java

I have implemented Python-style generators within Java. I might be reinventing the wheel here, but I feel that the ability to define a Generator with an anonymous class is the most flexible approach. ...
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4answers
443 views

Thread-safe, Convenient and Performant Random Number Generator

I need to generate a lot of pseudo-random numbers in my software. I'm trying to create a elegant (syntax-wise) and performant class that would allow me to generate such numbers and perform other ...
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5answers
716 views

Reducing contention in thread-safe LruCache

I was looking for a in-memory cache class, but couldn't find any in the .Net Core framework; luckily I found one already implemented here. I made some minor modifications to it and tried to make it ...
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2answers
89 views

Server and Client programs for guessing game

I recently had to complete this for a school assignment and I really enjoyed it, but was hoping someone with experience in OO design or maybe just Java in general could have a look and point out ...
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0answers
39 views

Execute a command repeatedly until a stop message is received

I'm trying to create a script that receive command from other script, and based on the command received it will execute a method with a while loop or stop it. I manage to make it works with the code ...
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71 views

Would log4j be more efficient to utilize than the logger I implemented (Code Below)?

I recently made a logger program implementation in my game engine. Which logs any thing that I send it in either a file or the System.out printstream. I use it like this: ...
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Invoking parallel threads of a nslookup command in python

I've written below python script just to invoke parallel threads of a command nslookup linux-host01 dns-server, i'm Just trying to flood the DNS Server ...
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2answers
120 views

PLINQ code analysis in terms of efficiency of cryptographic hashes generation

I have the following code that I wrote in order to find the correct password by generating hashes out of all possible combinations and comparing each of them with the target. I'm trying to make ...
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1answer
73 views

Implementing a thread pool for task execution

I wanted to experiment with a reusable thread pool that allows to add tasks and execute them repetitively. After going through, https://github.com/progschj/ThreadPool and another Stack Overflow post ...
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4answers
1k views

Unix chat server making communication between terminals possible

This Server handles clients communicating with each other. Because I was not willing to actually give every client a name, they are named by their socket's file descriptor. This is my first ...
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1answer
70 views

A minimalistic kind of read-copy-update class

This is a very simple read-copy-update (RCU)-inspired synchronization class: ...
3
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1answer
107 views

Cancelable AsyncLazy that is thread-safe

I've been thinking about the AsyncLazy<T> class that Stephen Toub and Stephen Cleary present in various resources such as this. I am trying to find a way to ...
3
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1answer
133 views

Simple sharding of delimited files to more sophisticated

A while back I came across the issue of having a large delimited file where I wanted to simply parallelize my python code across each line of the file. However, doing so all at once either took up too ...
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3answers
126 views

Thread-safe “singleton” that destroys object when not used anymore

I'm working on some legacy code which uses the singleton pattern. The problem I have with the traditional singleton is that the instance lives until the program terminates. This is messing up the ...
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0answers
65 views

Lock-free pooled queue

I am attempting to create a lock free pool of resources and I need the ability to access any one that is not already accessed and then return it back when I do not need it. This will happen very very ...
3
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1answer
66 views

Asynchronous hardware communication - Library Design

I've got some equipment ("tool") that communicates over CANbus that I need to communicate with. I'm using a USB->CAN dongle that provides a basic .Net control library. I'm in the process of writing ...
4
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2answers
494 views

Unisex Bathroom problem without semaphore

Could I ask you to evaluate my solution to Unisex Bathroom Problem? Problem description An office has a bathroom that can be used by both men and women, but not both at the same time. If a man is ...
4
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1answer
126 views

Factorial calculation UI freezes on loading many items in ListBox

I've been experiencing this performance issue for about 3 days and really need your help. I'm a novice at c# and cannot understand what I can do to optimize my application. The problem is that the UI ...
3
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1answer
108 views

Invoking thread for each item in list simultaneously and returning value in Java

I made a wrapper for an API that I am using, basically what I'm doing is sending in a list of Series objects and for each item in the list, a thread ("worker"?) ...
2
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0answers
50 views

Mutex lock benchmark

I'm trying to measure how many CPU cycles a mutex lock takes. Can you find any problems in my mutex lock benchmark? ...
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0answers
32 views

Lightweight lock using OMP atomic

I am working on a Monte Carlo simulation using OpenMP multithreading. To avoid race conditions when multiple threads work on the same resolution element, I have implemented the following ...
2
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0answers
66 views

Parallel Miller-Rabin Prime Test in Haskell

I implemented a prime number finder using the Miller-Rabin prime test in Haskell and it seems to be working. You enter a number and it finds the next prime following that number. I also tried to make ...
4
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1answer
66 views

Suspend and resume a thread using signals

The other day I ran into this question on stackoverflow. Just for curiosity I wanted to implement suspending and resuming the thread, so I used signals and used ...
2
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0answers
15 views

Thread safe Shareable and Splittable Buffer with Safe Memory (Project)

Backstory This is a buffer I wrote for use in multiple personal projects. It is designed to handle pretty much any data in pretty much any way. In particular I intend to use it in such instances as ...
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2answers
75 views

Thread-safe stack in Java with fixed capacity

Implement a multi-threaded stack, with freedom to use existing implementations of stack. On top of being thread-safe, it must block (not busy-wait) a pushing thread when stack is full and a ...
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1answer
29 views

Two-Part Hurdle Model Simulation with Bootstrapping

I am running a simulation study where I am using two-part hurdle modeling on different effect sizes. I tried to stream-line my code for the best optimization including foreach loops and ...
3
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1answer
120 views

Determine concurrent access to a function

Someone asked here how to determine a function is being called from multiple threads. My take on this is that they are asking about concurrent access not sequential access. The accepted answer ...
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1answer
85 views

C++ Windows Directory Watcher

This was a small project I did the other day because I wanted to explore a solution to hot-reload some files in another project. My requirements were: Act in it's own thread Be able to watch ...

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