Questions tagged [concurrency]
In computer science, concurrency is a property of systems in which multiple computations can be performed in overlapping time periods. The computations may be executing on multiple cores in the same chip, preemptively time-shared threads on the same processor, or executed on physically separated processors.
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Reading one source Stream by multiple consumers asynchronously
The problem was using single Stream from the HTTP response in multiple consumers simultaneously. For example: while data is loading, I want write it to the some ...
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44 views
Why is my Python thread pool faster than my Go worker pool?
I have recently been digging into understanding Golang concurrency, in particular the use of channels and worker pools. I wanted to compare performance between Go and Python (as many have done) ...
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Run non overlapped periodical tasks on user specified executor
I have concurrency tasks in my module: user code is able to instantiate my object and specify Executor service, then user can submit requests to this object which ...
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1answer
41 views
Concurrent Queue with enqueue and dequeue using Stack as underlying data structure
This is a mix of data structure and multi threading concept based question. (This is only for understanding and learning purpose) The language for the solution : Java
A Queue with FIFO behavior needs ...
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1answer
62 views
C++ latch implementation
Since std::latch is not in many standard C++ libraries, I tried implementing my own, is it OK from memory ordering perspective or ...
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1answer
46 views
Command line dictionary tool, using webscraping
This is my first proper Go program, after completing Go by Example and https://tour.golang.org. I have a background in Python.
This program scrapes definitions from Wordnik, then prints them nicely ...
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0answers
38 views
infinite generator with eviction
I made a struct that will loop through a list, and return the next element on calls to the Get() method.
It also allows to remove elements from the list by calling the Evict() method, and is safe for ...
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1answer
66 views
Banking application - Optimizing java multi-threading code
I created a simple Bank application to make multiple transactions between multiple accounts. It is working as expected. But I want to know can I make the code more optimized.
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1answer
57 views
One consumer and two producers using threads
I have based this code on Producer-Consumer Threading on Real Python.
The idea is that I have 2 producers:
One producer will give result every 0.4 to 0.7 seconds, depending on REST call.
The second ...
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42 views
Dealing with Future#get and InterruptedException Sonar java:S2142 [closed]
In some legacy code I have inherited, there is a snippet that looks similar to this.
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0answers
28 views
Executing two database queries concurrently in Go [closed]
I would like to execute two database queries concurrently for quicker response time. Since channels seemed to be too verbose, I came up with the solution below. However, I'm not very confident about ...
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2answers
51 views
Simple multiple producer and single consumer concurrency pattern
Anyone please review and share your feedback for the following code.
Multiple producers generate random integer numbers and a single consumer receives it to display only odd numbers out of it.
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1answer
120 views
A multi-thread Producer Consumer, where a Consumer has multiple Producers (C++17) - Part 2
This post is based on A multi-thread Producer Consumer, where a Consumer has multiple Producers (C++17). I am trying to build a Consumer that consumes data from ...
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A multi-thread Producer Consumer, where a Consumer has multiple Producers (C++17)
EDID: Thank you very much for your feedback. I updated the code and opened a new post for the updated version. See here.
This post is loosely based on A multi-threaded Producer Consumer with C++11.
...
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2answers
363 views
Multi Threaded High Performance txt file parsing
EDIT
A port of Björn's answer to C++ with further improvements at bottom achieving up to 2.4GB/s on the reference machine.
Text file parsing and processing continues to be a common task. Often it's ...
3
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0answers
788 views
Hosted service for queuing and running tasks in parallel in ASP.NET Core
I am attempting to construct a background service for an IIS-hosted ASP.NET Core project that basically queues tasks and runs them, and I decided to go with the ...
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2answers
61 views
Recursive Mergesort using goroutines
When learning a new language, one of my first tasks I like to go through is writing a few different sorting algorithms in that language to help familiarize myself with the syntax and see if there are ...
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157 views
Thread Safe Bank Transaction: Deposit, Withdrawal, Check Balance and Transfer in Java
I have made a class which is a thread-safe implementation supporting Deposit, Withdrawal, Check Balance Querying and Transferring of money.
I have a class Account:
...
3
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1answer
81 views
Code to print even and Odd number using two threads
Below I am giving you my code which I wrote to print even number using even thread and odd number using odd thread sequentially.
Could anyone please validate my code whether it is correct way of ...
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1answer
66 views
Concurrency-safe task scheduler
I'm trying to do some task scheduler and worker. Tasks are added to the queue from which worker retrieves and processes them. Tasks from one queue must be executed sequentially. Tasks from different ...
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1answer
629 views
Simple Producer-consumer implementation in Python
I implemented a simple solution to the Producer–consumer problem
that I'd love for you to take a look at.
The producer simply adds random numbers to a queue and the consumer (from a separate thread) ...
2
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0answers
67 views
Concurrent execution and coordination of C# tasks
I have a class, 'TaskCoordinator' which has 'BaseTask's applied to it.
The BaseTasks have OnStarted, OnFinished and OnCancelled events which are triggered to notify the calling class of their events....
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0answers
42 views
Concurrency control between a non-blocking and a blocking methods
In this program, there is a list of Holders that is managed by a singleton class. Each of the Holders keeps a copy of the ...
4
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1answer
1k views
Asynchronous parallel ForEach implemented using Task.Run
I wrote a simple implementation of aysnc parallel.ForEach( ... )
All it really does is create a list of tasks and wait for them all to complete and aggregate the ...
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1answer
44 views
Count Words in Quotes Fetched from Website
I have solved the following exercise and would like to get some feedback on my implementation.
Create a function that uses futures to parallelize the task of downloading random quotes from https://...
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4answers
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AsyncDictionary - Can you break thread safety?
This class is an Async/Await wrapped Dictionary. Of course it doesn't technically implement IDictionary, but the functionality is basically the same as an IDictionary. It achieves similar ...
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2answers
858 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 ...
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1answer
132 views
Find shortest path in the matrix for multiple objects
I have the implementation of A* search algorithm that allows to find the shortest path from start to goal.
The implementation looks like this
...
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2answers
164 views
Async concurrency prevention class
Because I'm quite naive regarding C#'s Task Asynchronous Programming and concurrency in general, and because it's so difficult to test, I'm concerned about the safety of this code. It's likely that ...
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1answer
71 views
Concurrent Queue Adapter
There's lots of code out there for basic adapters of std::deque to provide a thread-safe queue. I've adopted that, but wanted to provide a relatively full analog to ...
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2answers
548 views
Parallelized for loop in Bash
I am using a Bash script to execute a Python script multiple times. In order to speed up the execution, I would like to execute these (independent) processes in parallel. The code below does so:
<...
4
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1answer
129 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
120 views
Performing an action which may return other actions to be performed, concurrently
I have a program which, at its core, involves repeatedly performing an action on some value, and based on that action also returning a list of new values to perform that action on. The pure version of ...
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0answers
24 views
Process 2 lists concurrently with the first list adding to the second [closed]
I'm new to multi-threading and concurrency. I've got 2 lists that I want to process concurrently. Processing both lists requires a lot of time.sleep() and waiting for other servers to finish, so I ...
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2answers
236 views
Multi-Threaded Cellular Automata Lab
I am trying to improve the performance of my cellular automata lab. I have two arrays of Doubles representing the current values and the next values.
If I run the ...
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0answers
21 views
Take a list of ascii strings from a file and hash them using python threading
How can I do this in a more performant way? I'm concerned that throwing the data in a queue like this is defeating the purpose of yield from the ...
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0answers
41 views
Comparing Java Semaphore versus ReentrantReadWriteLock
In this post, I attempted to compare the performance of two concurrency constructs:
java.util.concurrent.Semaphore,
...
2
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0answers
424 views
Many-readers-one-writer with semaphores and multithreading
I've been looking for a solution to the may readers one writer in Java.
I was intrigued by this question posted here and I read the Wikipedia entry about it.
So far, I've reached a fine solution, or ...
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1answer
3k views
Safely executing background tasks in parallel in ASP.NET Core
Context and initial idea
I'm trying to teach myself the CQRS and Event Sourcing patterns by developing a simple ASP.NET Core application, loosely following Greg Young's example CQRS implementation on ...
7
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1answer
134 views
Quiz game with timer
This is my first Go program. I would like to know what could be improved, what is done wrong, and anything else that I should know. The CSV contains 10 questions with the 10 answers separated by a ...
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2answers
82 views
Download and save bulk URL concurrently
I am new to Go and wrote program to download and save bulk URLs concurrently. It is working correctly, but I would like to make it more efficient and follow best practices.
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2answers
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java Thread-safe LRUCache implementation
What is best way to implement thread-safe LRUCache in java?
Please review this one.
Is there any better approach which can be taken here?
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1answer
104 views
Finding the longest Collatz sequence using Go, concurrently
I am working through this problem on project euler.
Basic purpose of the code:
...
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1answer
181 views
Reader Writer SpinLock
I'm quite new to C++ and want to focus on writing performant multithreaded code because I will try to port our company internal GUI framework which is currently implemented in C#. So I'd love to get ...
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2answers
73 views
Upload a directory, in parallel, to an artifact repository
This code uploads an entire directory and allows for its reparenting on a remote server (an artifact repository).
Three concerns:
Copying the files locally takes a lot of space. Ideally, I could use ...
2
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2answers
2k views
Golang execute several go routine in loop and then wait
I'm new in Go and excited with its easy-to-use concurrency implementation. However I'm not sure if I'm doing it right in Golang way.
Consider the code where I spawn ...
2
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1answer
54 views
Batch downloading to file or memory
This is likely my first useful piece of Rust code. Planning to crate-ify it. It works.
...
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2answers
117 views
Using two threads to increase RFC1951 Deflate compression performance
I have modified my implementation of RFC 1951 "Deflate" compression to use two threads. One thread performs the LZ77 matching, looking for sequences of at least three bytes that occur earlier in the ...
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2answers
116 views
Automatic RAII wrapper for concurrent access
Probably many people had to work with multithreaded applications with C++ and can understand how messy can be fine-grained locking of objects.
So once in a while I came to idea of implementing some ...
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0answers
72 views
Critical section around given key
I would like to know if there is any pre-existing implementation of my solution so I don't have to reinvent the wheel.
What I'm trying to create is an utility which allows me to create critical ...
