All Questions
Tagged with c++ concurrency
65
questions
3
votes
1
answer
62
views
A Simple BlockingQueue implementation in C++
I'm just dusting off my C++ knowledge in area of multithreading.
I started with implementing a producer-consumer pattern inspired by https://jenkov.com/tutorials/java-util-concurrent/blockingqueue....
- 41
2
votes
1
answer
97
views
Multi Threaded File Processing C++
Background:
The program reads 1000000 lines in the file. Every four line will be parsed into an object in a vector. If it has 2 objects with the same name, it will drop 1 object and increment one of ...
- 23
2
votes
1
answer
839
views
Efficient parallelization of small tasks
Problem statement: Consider a scenario where a vector of very small tasks, each encapsulated within a class 'Task' with a thread-safe method Task::process(), needs to be efficiently processed in ...
- 121
4
votes
4
answers
2k
views
Yet another shared_ptr implementation for learning purposes
C++ shared_ptr implemented as a coding practice and learning purposes.
It uses std::shared_ptr interface.
Basic tests are included (using single header Catch 2)
Some methods are omitted to keep the ...
- 141
4
votes
1
answer
126
views
Packet generation and consumption
I have the following simplification of a program which consists of 2 threads. One thread pushes packets to the back of a deque while another waits for user input before performing a "heavy" ...
- 369
6
votes
1
answer
911
views
Simple, fool-proof pattern to execute tasks in parallel
Assume I have a type task_info that stores the task-specific data needed to execute the task. A std::vector of those is built ...
- 233
3
votes
2
answers
293
views
atomic spinlock mutex class
This here is the follow-up to this question. I was recommended to implement a Lockable type (similar to std::mutex) that can work with ...
- 935
2
votes
1
answer
186
views
C++20 simple RwSeqLock
I recently discovered the atomic wait/notify mechanism in C++20 and wrote this readers-writer lock in the style of Linux kernel Seqlock. Writes have to be inside a lock/unlock, while reads are ...
- 23
2
votes
1
answer
132
views
Thread Pool Class
I have a thread_pool class, that mimics std::thread. (I would have liked std to have a pool, but alas that is not the case.)
thread_pool.h
...
- 462
4
votes
1
answer
841
views
Thread Safe Queue
I have a thread safe queue in my library c9y. It is generally used as a task queue in the task_pool class, but in can be used for any producer / consumer problem.
queue.h
...
- 462
2
votes
1
answer
477
views
Sender/Receiver threads using std::unique_lock and std::condition_variable
The code below is a sender/receiver setup in C++ where the sender is in one thread, the receiver is in another, and the data being sent/received is "shared" (global). The code uses the ...
- 79
2
votes
1
answer
2k
views
C++20 Multi-queue Thread Pool with Work Stealing
This is a follow up to my previous post which also follows up on my first post regarding my thread pool implementation. I have since made some further changes and attempted to improve performance with ...
- 420
3
votes
1
answer
275
views
Lock-free, thread-safe trie container
This is a Trie data structure for mapping strings to integers or pointers in O(n) time. Based on the idea that we never delete anything from the container, we can perform concurrent read/write ...
- 421
5
votes
2
answers
2k
views
C++20 Single Queue Thread Pool
This is a follow up to my previous post. I've made a number of improvements to the thread pool and corrected some bugs as well.
The most up to date version of the code is available on my Github.
I ...
- 420
2
votes
1
answer
3k
views
C++14 Lock-free Multi-producer, Multi-Consumer Queue
Introduction
This is a follow-up to a previous question of mine, where I presented another queue of the same type to get some feedback on it. Some people pointed out some fundamental errors I had ...
- 95
7
votes
3
answers
1k
views
Lock-free multi-producer / multi-consumer queue in C++
I've been working on a lockless multi-producer, multi-consumer queue in an effort to learn as much as I can about concurrency, without the use of mutual exclusion. The queue uses a bounded ring buffer ...
- 95
4
votes
1
answer
189
views
Order guaranteed recursive_transform template function implementation with execution policy in C++
This is a follow-up question for A recursive_transform Template Function with Execution Policy, A recursive_transform Template Function Implementation with std::invocable Concept and Execution Policy ...
- 5,392
5
votes
2
answers
4k
views
C++20 Thread Pool
I've implemented a thread pool using C++20. I'm fairly new to concurrently/multi-threaded programming and wanted to work on a project that I could learn from while also getting to know some of the new ...
- 420
3
votes
2
answers
459
views
C++11 revised `std::latch` implementation
This question follows up on this question.
After turning the while-loop into a conditional wait using std::condition_variable, I ...
- 43
1
vote
1
answer
451
views
Implementation of a latch
As an exercise to learn more about multi-threading and atomic operations work in C++, I decided to implement a latch class in C++11 loosely based off of std::latch ...
- 43
5
votes
3
answers
1k
views
Single Producer Single Consumer lockless ring buffer implementation
I am writing a simple ring buffer for my own education. Below is a crack at a strategy described in http://www.cse.cuhk.edu.hk/~pclee/www/pubs/ancs09poster.pdf : Producer and Consumer keep local ...
- 59
1
vote
1
answer
123
views
Concurrent dependant routines in a gui application [closed]
The idea is that, in my application I have 5 routines named long_process_1, long_process_2, ...
8
votes
0
answers
404
views
Implementing GSL synchronized_value
Core Guidelines mention a type synchronized_value<T>, which supposedly pairs std::mutex with the internal value. I couldn'...
- 469
4
votes
1
answer
987
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 ...
- 141
1
vote
1
answer
1k
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 ...
- 175
6
votes
3
answers
3k
views
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.
...
- 175
11
votes
3
answers
6k
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 ...
- 2,475
7
votes
1
answer
116
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 ...
- 253
4
votes
1
answer
289
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 ...
- 141
4
votes
1
answer
535
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 ...
5
votes
2
answers
461
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 ...
- 51
3
votes
0
answers
1k
views
Linked list with hand-over-hand locking
Follow-up to this question: after reading the comments, I decided to redesign my linked list to have a cursor that only contains one node and implement the interface similar to the one of forward_list ...
- 183
2
votes
1
answer
251
views
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 ...
- 108
4
votes
0
answers
285
views
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 ...
- 363
4
votes
1
answer
96
views
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-...
- 143
4
votes
1
answer
3k
views
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 ...
- 273
1
vote
0
answers
772
views
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 ...
- 11
5
votes
2
answers
1k
views
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 ...
- 19.4k
3
votes
1
answer
2k
views
Work stealing queue
I implemented work stealing queue inspired by Sean Parent's talk on code::dive 2016. Full implementation is here. I am looking to get feedback on improvements to make code more effective and common ...
- 143
4
votes
3
answers
6k
views
Matrix multiplication with OpenMP parallel for loop
I tried implementing matrix multiplication with parallel for loop in OpenMP as follows. It runs correctly but I want to make sure if I'm missing anything. How does this determine the number of threads ...
- 221
4
votes
1
answer
3k
views
Blocking queue implementation with std::unique_ptr
I implemented, somewhat closely based on this implementation, a blocking queue with emphasis on filling up first. So if one producer and one consumer thread are using the queue, the producing queue ...
- 43
8
votes
3
answers
3k
views
The dumbest (futex-based) mutex
After reading Ulrich Drepper's "Futexes are Tricky", I have written the following "dumbest mutex" in C++14 using the Linux futex primitives. This mutex is simpler ...
- 19.4k
9
votes
2
answers
1k
views
C++11 Blocking connection pool with auto release
Relatively new to C++. Please help me understand the potential issues with the following blocking object pool.
...
- 189
0
votes
1
answer
1k
views
Turn a non-blocking concurrent queue into a blocking concurrent queue
Microsoft Visual Studio offers a non-blocking concurrent queue class, concurrency::concurrent_queue, based on Intel's TBB. I am using this as a base for a blocking ...
- 303
2
votes
0
answers
567
views
RCU in C++11 using std::shared_ptr and a little more
Here's some code I wrote to solve a problem at the server I'm working on. Is this valid? I've tested it, and it works, but I would like some opinions on this.
It's basically a ...
- 39
3
votes
2
answers
2k
views
1
vote
2
answers
7k
views
C++ thread safe queue implementation
I'm using this class for producer-consumer setup in C++:
...
- 183
2
votes
3
answers
10k
views
Simple parallel_for_each in C++
I need to parallelise a for loop that does quite a lot of processing over thousands of items. I came up with this basic loop that seems to work quite effectively on ...
- 121
3
votes
2
answers
241
views
Concurrent for loop in C++ - follow-up
I have incorporated all the cool points made by ChrisWue in the initial iteration of this post.
Now, I am not reinventing the wheel for my concurrent queue, but use internally ...
- 28.9k
5
votes
1
answer
743
views
Concurrent for loop in C++
(See the next iteration.)
I have this easy to use facility that maps input elements to output elements concurrently by the means of a thread pool:
concurrent.h:
...
- 28.9k