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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Java Concurrent Recursive API Access
I don't get to write multithreaded applications very often, so be gentle with my threads :-)
I have an API input which contains a "score" and then a bunch of child nodes which also have scores, and ...
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Drawing the Mandelbrot with multiple threads in rust
The code below draws the mandelbrot set for { z | z∈ ℂ, -2.2 ≤ Re(z) ≤ 0.6, -1.4 ≤ Im(z) ≤ 1.4} into a 300×300px png image. For each pixel,
if the sequence {zi} is found to ...
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HTTP Load test with Golang
I am a golang novice... I am trying to write an application that takes in many requests - up to a sustained 10000 HTTP posts/sec and post the payload to two back-ends in parallel (5 second timeout). ...
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Concurrent access to data with QReadWriteLock
Using Qt, I've got this code in order to protect access to some shared data between threads. I'm pretty sure the idea is correct, but I don't know if RVO and/or RAII could potentially screw the ...
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Concurrent fire and forget async task queue
I had to do a lot of IO stuff on my server running Node JS where I did not really care about the result of the operations. The list of incoming tasks could be huge, so I had to limit the number of ...
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An in-memory copy of the GDAX order book for an arbitrary cryptocurrency, updated in real time
GDAX is the cryptocurrency exchange owned and operated by Coinbase.
This code is intended to be the basis for an order-book-strategy trading bot.
I'd love feedback on my use of data structures, my ...
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Go task scheduler
This is the same problem as the Python task scheduler, but in Go.
I chose not to use a sync.Cond (I couldn't seem to get that right), but instead use channels.
<...
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Issue tokens concurrently with synchronization per client
I have an API application with token authorization. A token is valid for one hour. Each business client has its own instance of the API application:
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Asynchronous Message Passing
I'm implementing a method which has the purpose of waiting for a message (boolean value). Works, but can it be improved?
Code:
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Implementation of an ObjectPool
we are trying to implement an object pool. The objects contained are reusable but not thread safe, and creation costs a lot so we went with this idea.
We expect that the user of this object will need ...
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ConcurrentLinkedQueue Object Pool implementation
I have implemented this simple unbounded ObjectPool based on a ConcurrentLinkedQueue of WeakReferences. I have a thread-unsafe object that is pretty expensive to create, and most of the time it will ...
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Simple concurrency implemented in Python
Purpose of the question: learn more about ways to implement concurrency in Python / experimenting.
Context: I want to count all of the words in all of the files that match a particular pattern. The ...
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Concurrent Data Manager with minimal synchronization
So I have my own library to organize advanced critical sections at GitHub. It's based on the ResourceDataStorage class which is responsible for creating, storing and clearing resource records. I've ...
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ReadWriteSerializer
I am developing a C++ kernel, and I've got the need for manipulating huge data structures before the task-scheduler runs - it means in a non-preemptive environment.
For this, I have developed a read-...
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Concurrent hero vs monster program
I have made a simple concurrent program. It represents a battle between a hero and a monster. I am beginner in concurrency so I just want to hear your opinion. What are bad and good sides of my code ...
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Use of concurrency to generate combinations
I have the following package to generate combinations from a slice of bytes:
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Worker, Pool and Jobs
I created a snippet of code that allows me to create a worker pool, and from that worker pool I can run a bunch of jobs.
I can configure each job to have a retry limit, and set a callback that will ...
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Pub/Sub Broker Subscriber Interface
I'm working to build out a Subscriber interface for handling at-least-once messaging semantics, so I can produce different brokers. Here's my interface thus far:
<...
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Tool to calculate the average time that takes for a GitHub pull request to get merged
I'm learning Go, and this is my first attempt at a command-line tool that uses the GitHub API to calculate the average time that takes for a pull request to get merged for a particular organisation or ...
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Race condition of initialization with fail safe
I have the following usecase, I have a multi threaded environment and I want to initialize some parameters only only. The thing is that when I initialize the parameters I call a function that ...
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A Game of Life application, with mouse clicks
I have a Game of Life program that has a grid[][] array which is populated by Cell objects. If there's a cell in a grid square, ...
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A portable parallel loop construct in C89 - follow-up
This is a follow-up question to A portable parallel loop construct in C89. I have incorporated all the good points made by vnp. Now my code looks like this:
parallel_for.h
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A portable parallel loop construct in C89
(There is a next iteration available.)
I was practicing writing some portable C89 code and came up with this parallel for loop construct. Basically, if you have a ...
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Implementation of a cellular automata to model breast cancer
I've created a program - it's an implementation of the cellular automata described in this paper (can't find a free PDF, sorry - anyway it's not really relevant to this question). The CA is ...
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A "zero copy" concurrent queue in C++ that supports exactly two threads; one for pushing and one for popping
One thread is limited to one action (i.e. there is a push-thread and a pop-thread and the push-thread can't pop and vice versa). By "zero copy" I mean no copying of data (mostly C++ structures) will ...
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Modelling deadlock in cyclic pipelines in Haskell with coroutine libraries
I'm modelling two processes which have been put into a cyclic pipeline - the output of each feeds into the input of the other - so as to work out when they've deadlocked (i.e., neither can progress ...
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Managing socket pool per datacenter
I have a list of sockets per datacenter (in general, I have around three datacenter and each datacenter having 20 sockets, so in total I have around 60 sockets). Now I have 20 business threads which ...
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Send data on a socket from multiple threads
I have around 60 sockets, 20 business threads and 1 pinger timer thread and I want to make sure each of those thread works on different socket every time so I don't want to share same socket between ...
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ArrayBlockingQueue in which queue head is removed if the queue is full while adding an element
I am trying to write a simple queue like ArrayBlockingQueue in which the head of the queue will be removed if the queue is full while adding an element. The class should just have the below public ...
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Stack for asynchronous processing
The following TaskStack processes input elements asynchronously based on a function that it receives at construction:
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Echo in Prolog with single print (new version)
In order to learn a bit more of Prolog, I implemented the echo command for SWI-Prolog.
I want a correct implementation, that is, it satisfies the following requirements:
It makes only one I/O call ...
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Golang: Improving communication between workers
Came back to the software side of my night vision security camera project after taking some time to learn about electronics and I found it a bit hard to retrace the logic of my program.
I have a ...
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Send records and retry them if acknowledgement is not received
I am using below class to send data to our messaging queue by using socket either in a synchronous way or asynchronous way as ...
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Processing concurrent AJAX requests
I am trying to process concurrent AJAX requests with vanilla JavaScript. Below is the sample code I've been working with
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A semaphore implmentation with Peterson's N process algorithm
I need feedback on my code for following statement, am I on right path?
Problem statement:
Implement a semaphore class that has a private int and three public methods: init, wait and signal. The ...
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golang concurrent tcp server
Go and concurrency noob here. I wrote a program to handle a tcp connection to index (and removes) packages. I want it to be able hundreds of connections and messages that might come in at the same ...
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Custom ThreadPoolExecutor/ThreadFactory in order to submiting callables upon incoming ActiveMQ messages
I have a service that is subscribed to a specific channel of ActiveMQ.
Every time a message arrives the service has to start a "job" (submit instances of Callables)...
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Socket server with consumer-producer design to handle concurrent connections
The usual way is to implement socket server to handle concurrent requests by creating new thread for each request.
Instead of this approach i tried to create a server using ...
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Python coroutines to write files
I'm refactoring a monster 176-line function into something more sensible and more testable. The function as it stands fails the 'one thing and thing well' test by doing many things:
Indexing through ...
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Do not share same socket between two threads at the same time
I have a code in which I am dealing with sockets and I need to make sure that I don't share same socket between two threads. In my below code, I have a background thread which runs every 60 seconds ...
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Convert FLAC files to MP3 in parallel on Ubuntu
I created a script to convert my FLAC music collection to MP3. I did this so that I can play the MP3 files in my car, as the integrated head unit only supports MP3 and WMA files. The script works on ...
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Heartbeat Server
I'm writing a toy heartbeat server. Each client, upon loading, registers itself and thereafter, sends heartbeats every X seconds. The server checks every ...
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Getting a serial number from shared table
I have a table that keeps track of a global serial number shared between several tables. This is not the PK or unique id for each table. It is like a case identifier. Every time users create a new ...
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Independently constraining task parallelism at different levels of a nested loop
I would like to performance test a REST API using C#. The API offers a list of endpoints, and each endpoint accepts page and size...
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Extracting large tar.bz2 folders in parallel
The bash below utilizes parallel to extract tar.bz2 folders with 9 files in them. The total size of each is around 60GB. Below ...
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Non-polling implementation of std::when_any()
The following — I claim — is a implementation of when_any from the C++ Concurrency TS, except without all the baggage around ...
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Purely functional octree and octree priority queue
I'm programming a game in Scala, and a lot of tasks are able to be done in the background. I've created a system in which each Future can be assigned a position in 3d space, and they are stored in an ...
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Permutation-stream based n-queens solution
Following is a very crisp solution for solving n-queens problem in Racket programming language. The method is to get all permutations (so that no 2 queens are in same line) and to check these for any ...
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Process array with x parallel executions
I wanted to create a function in JavaScript using jQuery's Deferred which executes a given function for each element in an array.
The function is intended for ...
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Two bidirectional Software UARTs with AT89S52 microcontroller
I have learned one way to read from a serial port via software UART is via timer interrupts. I have made an implementation of receiving data from one serial port below. I haven't tested it yet because ...
