Questions tagged [thread-safety]

A piece of code is thread-safe if it only manipulates data structures in a way that allows consistent execution of this code by multiple threads.

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votes
4answers
399 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 ...
9
votes
4answers
2k views

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 ...
2
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1answer
91 views

Simple, flexible, and thread-safe key/value memory cache

MemoryCache.cs ...
6
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2answers
244 views

Wrapping IMemoryCache with SemaphoreSlim

I need simple caching for one of my web-services so I use the Microsoft.Extensions.Caching.Memory package. I wrapped it with ...
4
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0answers
91 views

Toggle any application feature ON or OFF - follow-up (v2)

This is the second version of my FeatureToggle service (see previous question). It still has the same purpose which is to help control whether a feature is ...
2
votes
0answers
61 views

Await data coming from an event [closed]

This is a USB related question, but the problem is not USB specific. When reading data from a USB endpoint, there are two patterns I am concerned with. Request/Response like HTTP (done over the Bulk ...
4
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0answers
67 views

Type & Thread-safe Logger Implementation

So I had previously posted this question and asked for some feedback regarding my (now) header-only logging system and figured it would be a good time to go back to the changes I made it and see if it ...
3
votes
1answer
84 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 ...
5
votes
2answers
114 views

Safe Dispose of Timer

I am currently refactoring a larger solution where the compiler gave multiple warnings about disposing the used System.Timers.Timer instances. The timers are ...
3
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0answers
63 views

Use SemaphoreSlim to control access to a resource

We have an existing situation in an MVC ASP.NET app where it's possible for two threads to come back asynchronously, one from an external api(the payment gateway) and one from within the browser for ...
3
votes
3answers
106 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 ...
2
votes
0answers
58 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 ...
2
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0answers
47 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? ...
5
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2answers
149 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 ...
5
votes
1answer
76 views

SQS subscriber pattern in background service

I have the below code to pull messages from a FIFO SQS queue. Using the while (IsRunning) loop makes me feel to question the code design. Is there a pattern I am ...
4
votes
2answers
66 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 ...
5
votes
1answer
60 views

Rate limiting variable-duration operations over a time interval

I want a rate-limiter that permits, at most, N operations over T seconds. I found a sample implementation here but it makes an assumption that operations complete in a predictable, consistent amount ...
3
votes
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 ...
1
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0answers
47 views

Near immutable, thread safe Builder

I'm writing a torrent streaming client. The plan is to wrap WebTorrent-cli and provide a Java interface to observe download state, cancel or pause downloads etc. Anyways, I came up with the following ...
4
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0answers
229 views

Wait free triple buffer primitive

I'm trying to write a triple buffer that's wait free for a update + render loop after being bitten by lock starvation one too many times (on a different project, using a library). For reference, a ...
1
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0answers
46 views

C# asynchronous notification vector v2

As a result of my previous post, I have implemented / refactored my code and have started making successful use of my class. However I have come across a couple of new questions: The observer must ...
2
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0answers
36 views

Comparing Java Semaphore versus ReentrantReadWriteLock

In this post, I attempted to compare the performance of two concurrency constructs: java.util.concurrent.Semaphore, ...
6
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1answer
87 views

C# asynchronous notification vector

The purpose of this class is to efficiently notify another thread when data is available with minimal blocking to access/pass the data. The data reader/producer thread processes data in bulk which ...
1
vote
1answer
66 views

Multithreading to allow multiple clients on to a server and client requests handling

I have to create a client-server JavaFX application using MVC which does many operations consisting mainly in messages exchange. I'd like to know if this way to handle client acceptance and client ...
1
vote
1answer
262 views

Java concurrency exercise, implementing transfer of amount from one account to another

This is in continuation with my synchronized implementation of a bank account in Java. I am trying to implement bank accounts repository and method to transfer money from one account to another. My ...
7
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2answers
1k views

Synchronized implementation of a bank account in Java

I am trying to implement a bank account with Java in a thread safe way. My code looks like: ...
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0answers
35 views

threaded event loop “interrupt” unit test without deadlocks

I have an event_loop implementation (basically an event/command queue and an exec function). I have added ...
6
votes
1answer
619 views

Implementation of thread-safe vector

I have implemented a thread safe vector, based on std::thread and std::vector. I am new to many of the patterns used in threading and was wondering if there's a more efficient way the locking can be ...
1
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0answers
106 views

An attempt of replacing CRITICAL_SECTION with std::mutex and std::lock_guard

I have an older class that I am working on and I'm updating it to remove "Windows" specific code. It had some "Thread Protection Code" that used CRITICAL_SECTION. I'...
1
vote
2answers
139 views

Thread-safe singleton cache (Python)

In a service I'm developing I'm using three cloud services (five if you count additional two streaming services I have to create that are used by those cloud services in turn) and to orchestrate bits ...
0
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0answers
48 views

Spring Component Thread Safe

Recently I refactored an application to start using spring, and after some research, I found out that @Component is not thread safe. The class is this: (It's a converter from xlsx to json string) <...
1
vote
1answer
31 views

Spring TaskScheduling with HashMap

I am currently developing a Task Scheduler to run different methods at a certain time. In general it is a Spring-boot application an task execution/scheduling is just a very tiny piece of the whole ...
2
votes
0answers
50 views

Thread-safe sensor interface with observer and strategy patterns

I have a thread-safe API for an observable Sensor. The concrete type of the Sensor is chosen in the ...
2
votes
0answers
136 views

thread safe queue with interrupt function

I try to implement a thread safe queue with the interrupt function (interrupt all threads who are blocking to take data from queue). ...
2
votes
1answer
104 views

Simple multithreading C project

I'm fairly new to C, and this is my first time using pthread. I am pretty sure I implemented it correctly, however I'd like to verify it is indeed executing the ...
2
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0answers
74 views

Repeating a task that may fail (in parallel)

Almost like this question here, I'm playing with some methods that may fail, but in my case, the method failing is not a exceptional case; it just means I need to try running it again. The method I'm ...
4
votes
0answers
68 views

“Lock-free” one-shot event manager

Giving a review to Oachkatzl and recently about some other synchronization problems (Lazy with invalidate and some node-locking list), I wanted to test my skills and redesign it in most light-weight ...
4
votes
3answers
112 views

Really easy synchronised access to an IEnumerable without boilerplate code

Often when reading data from a sequence (IEnumerable<T>) in multi-threaded code, a consistent snapshot needs to be taken inside a ...
5
votes
1answer
244 views

Linked list node-level locking

I am new to C++ threading library. I would love to get some comments on how to improve this code (if there are possible bugs, I would appreciate that feedback too). In particular, I want to refactor ...
1
vote
0answers
48 views

Multithreaded FRC Robot Framework (Kinda Big)

I'm working on some code for an FRC Robot. I wanted to see if there's any obvious improvements that can be made here, that stands out, or stuff I should avoid doing. This is a test bed for the base ...
7
votes
1answer
163 views

Threadsafe oneshot-event which fires on subscription if the event was fired in the past

Assumptions Basically, a Connection class has a "Disconnect" event. Subscribing to this event isn't thread-safe, because the disconnection may fire from another thread right before I subscribe. So ...
5
votes
0answers
82 views

Testing application stability by throwing random diagnostic exceptions

I'd like to be able to better test application stability. Usually when you're doing this, you run the application and keep your fingers crossed that it won't crash when an error occurs (be it a ...
1
vote
1answer
1k views

Print odd and even numbers using two threads in Java

I was asked below question in an interview where I need to print out even and odd numbers using two threads so I came up with below code one without synchronization and other with synchronization. <...
1
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0answers
145 views

Thread-safe Java class for managing XML files <> domain models

This Java class (aka application component) role is to handle a series of XML files stored in the file system. It must convert those XML files to the corresponding application domain model, and it ...
1
vote
0answers
34 views

Drawing sprites and adding new ones

I have some code that draws sprites and and allows new ones to be added. To do this, I use 2 lists: 1 for the sprites that need to be drawn, and one for the new sprites that need to be added to the ...
3
votes
3answers
326 views

C++ upgradable RW lock implementation

I am using VS 2017 with C++ 17 standard set on Windows OS. What I'm missing in couple of heavily threaded projects is synchronizing mechanism that can be atomically upgraded from shared to exclusive ...
7
votes
4answers
763 views

Caching Color-Bitmaps as MemoryStreams

I am in the need to cache Bitmap's in a memory-optimized way because the API I am building will need to process many colored ...
1
vote
1answer
1k views

Static wrapper class for log4net Logging - thread safety

I'm using log4net in my application and have a static Log class which creates an instance of ...
2
votes
1answer
229 views

Run two computations in parallel, and return the results together

I am reading the "Learning Concurrent Programming in Scala" and there are exercises in the end of each chapter. One of exercises is Implement a parallel method which takes two computation blocks a ...
1
vote
1answer
269 views

Thread safe queue with buffer

I must implement thread-safe queue with buffer. According to the advice from the previous post: Thread-safe queue mechanism I resigned from Concurent Collections and used lock. Is it thread safe now? ...