Hacker News with Generative AI: Concurrency

Understanding the Go Scheduler (nghiant3223.github.io)
Understanding the Go scheduler is crucial for Go programmer to write efficient concurrent programs. It also helps us become better at troubleshooting performance issues or tuning the performance of our Go programs. In this post, we will explore how Go scheduler evolved over time, and how the Go code we write happens under the hood.

Go, Programming Languages, Concurrency, Performance Optimization

176 points by gnabgib 5 days ago | 26 comments

Project Verona: Fearless Concurrency for Python (microsoft.github.io)
As part of Project Verona, we have been developing a new ownership model for Python, called Lungfish.

Python, Concurrency, Programming Languages, Software Development

165 points by ptx 8 days ago | 144 comments

Lock-Free Rust: How to Build a Rollercoaster While It's on Fire (yeet.cx)

Rust, Programming, Concurrency, Performance, Safety

132 points by r3tr0 10 days ago | 60 comments

How async/await works in Python (2021) (tenthousandmeters.com)
Mark functions as async. Call them with await. All of a sudden, your program becomes asynchronous – it can do useful things while it waits for other things, such as I/O operations, to complete.

Python, Asynchronous Programming, Programming Languages, Concurrency

61 points by sebg 14 days ago | 7 comments

Unlocking Ractors: Object_id (byroot.github.io)
In a previous post about ractors, I explained why I think it’s really unlikely you’d ever be able to run an entire application inside a ractor, but that they could still be situationally very useful to move CPU-bound work out of the main thread, and to unlock some parallel algorithm.

Programming, Parallel Computing, Concurrency, Performance Optimization, Software Design

78 points by ksec 26 days ago | 0 comments

Swift 6.2: A first look at how it's changing Concurrency (avanderlee.com)
Swift 6.2 is the upcoming release of Apple’s native language. It’s currently in active development, and as you know from my weekly Swift Evolution updates, many proposals are currently being processed.

Programming Languages, Swift, Concurrency

21 points by ingve 31 days ago | 2 comments

JEP 506: Scoped Values final for Java 25 (openjdk.org)
Introduce scoped values, which enable a method to share immutable data both with its callees within a thread, and with child threads. Scoped values are easier to reason about than thread-local variables. They also have lower space and time costs, especially when used together with virtual threads (JEP 444) and structured concurrency (JEP 505).

Java, Programming Languages, Concurrency

34 points by ludovicianul 38 days ago | 9 comments

Concurrency in Haskell: Fast, Simple, Correct (bitbashing.io)
After nearly a decade of building embedded systems in C, C++, and Rust, I’ve somehow ended up writing Haskell for a living.

Concurrency, Haskell, Programming Languages, Functional Programming

193 points by ingve 39 days ago | 125 comments

Problems with Go channels (2016) (jtolio.com)
I’ve been using Google’s Go programming language on and off since mid-to-late 2010, and I’ve had legitimate product code written in Go for Space Monkey since January 2012 (before Go 1.0!). My initial experience with Go was back when I was researching Hoare’s Communicating Sequential Processes model of concurrency and the π-calculus under Matt Might’s UCombinator research group as part of my (now redirected) PhD work to better enable multicore development.

Concurrency, Software Development

160 points by mpweiher 41 days ago | 197 comments

Erlang's not about lightweight processes and message passing (2023) (stevana.github.io)
I used to think that the big idea of Erlang is its lightweight processes and message passing. Over the last couple of years I’ve realised that there’s a bigger insight to be had, and in this post I’d like to share it with you.

Erlang, Programming Languages, Software Development, Distributed Systems, Concurrency

331 points by todsacerdoti 42 days ago | 197 comments

In React {Transitions} = F(state) (jordaneldredge.com)
TL;DR: Thinking about the React component tree as modeling a state machine can help clarify the implications of asynchronous updates and React’s concurrent features.

React, State Management, Asynchronous Programming, Concurrency

39 points by captbaritone 46 days ago | 54 comments

Ask HN: Easiest and hardest concurrency models to use correctly? (ycombinator.com)
There's a lot of options for concurrency. In Python alone, you can use threads with shared memory, threads with queues, processes with queues, concurrent.futures, asyncio, trio, or AnyIO. Java now has a preview of structured concurrency and virtual threads in addition to regular threads. There's also the CSP model of Go, as well as the actor model and supervision trees of Erlang/OTP. Software transactional memory seems to be popular in the purely functional world but rare outside of it.

Concurrency, Programming Languages, Software Development, Comparison, Software Design

10 points by pkkm 47 days ago | 3 comments

How different languages and frameworks handle structured concurrency (github.com/jamesward)

Concurrency, Programming Languages

5 points by mooreds 49 days ago | 0 comments

A language for building concurrent software with confidence (github.com/inko-lang)
Inko is a language for building concurrent software with confidence.

Programming Languages, Concurrency, Software Development

26 points by znano 57 days ago | 3 comments

Ruby, Ractors, and lock-free data structures (iliabylich.github.io)
This story is about concurrent data structures in the context of Ruby. The goal here is to demonstrate how true parallelism can be achieved with global mutable state (which at the time of writing, is not supported by built-in Ruby primitives).

Ruby, Programming Languages, Concurrency, Data Structures

138 points by ksec 61 days ago | 9 comments

Ratomic: Provides Mutable data structures for use with Ruby's Ractors (github.com/mperham)

Ruby, Programming, Data Structures, Concurrency

9 points by ksec 61 days ago | 2 comments

Notes on structured concurrency, or: Go statement considered harmful (2018) (vorpus.org)
Every concurrency API needs a way to run code concurrently.

Concurrency, Programming Languages, Go, Software Design

6 points by HAMSHAMA 65 days ago | 1 comments

Lock Contention (maksimkita.com)
Recently, I revisited Resolving a year-long ClickHouse lock contention post and spoke about it at C++ Russia 2025 conference.

Software, Databases, Performance, Concurrency

96 points by stacyz 67 days ago | 1 comments

What's the Deal with (Ruby) Ractors? (byroot.github.io)
When Ractors were announced 4 or 5 years ago, many people expected we’d quickly see a Ractor-based web server, some sort of Puma but with Ractors instead of threads. Yet this still hasn’t happened, except for a few toy projects and experiments.

Ruby, Programming, Web Development, Concurrency

16 points by ksec 85 days ago | 0 comments

Concurrency bugs in Lucene: How to fix optimistic concurrency failures (elastic.co)
Debugging concurrency bugs is no picnic, but we're going to get into it. Enter Fray, a deterministic concurrency testing framework from CMU’s PASTA Lab, that turns flaky failures into reliably reproducible ones. Thanks to Fray’s clever shadow lock design and precise thread control, we tracked down a tricky Lucene bug and finally squashed it. This post explores how open-source heroes and tools are making concurrency debugging less painful—and the software world a whole lot better.

Concurrency, Software Development, Debugging, Open Source, Lucene

60 points by aoli-al 92 days ago | 15 comments

Exposing concurrency bugs with a custom scheduler (lwn.net)
Jake Hillion gave a presentation at FOSDEM about using sched_ext, the BPF scheduling framework that was introduced in kernel version 6.12, to help find elusive concurrency problems.

Concurrency, Linux Kernel, Debugging, BPF, Open Source

33 points by signa11 99 days ago | 5 comments

Ruby “Thread Contention” Is Simply GVL Queuing (island94.org)
For the longest time, I’ve misunderstood the phrase “thread contention”. It’s a little embarrassing that given I’m the author of GoodJob (👍) and a maintainer of Concurrent Ruby and have been doing Ruby and Rails stuff for more than a decade. But true.

Ruby, Programming, Threading, Concurrency

97 points by ciconia 109 days ago | 56 comments

Par: Process language with an interactive playground for exploring concurrency (github.com/faiface)
Par (⅋) is an experimental concurrent programming language. It's an attempt to bring the expressive power of linear logic into practice.

Programming Languages, Concurrency, Experimental Technology, Linear Logic

60 points by todsacerdoti 110 days ago | 4 comments

The Mythical IO-Bound Rails App (byroot.github.io)
When the topic of Rails performance comes up, it is commonplace to hear that the database is the bottleneck, so Rails applications are IO-bound anyway, hence Ruby performance doesn’t matter that much, and all you need is a healthy dose of concurrency to make your service scale.

Performance Optimization, Databases, Concurrency

227 points by thunderbong 118 days ago | 70 comments

The Mythical IO-Bound Rails App (byroot.github.io)
When the topic of Rails performance comes up, it is commonplace to hear that the database is the bottleneck, so Rails applications are IO-bound anyway, hence Ruby performance doesn’t matter that much, and all you need is a healthy dose of concurrency to make your service scale.

Rails, Performance Optimization, Database, Ruby, Concurrency

8 points by todsacerdoti 120 days ago | 2 comments

Ada for the C++ or Java Developer – Concurrency (adacore.com)
Java and Ada both provide support for concurrency in the language. The C++ language has added a concurrency facility in its most recent revision, C++11, but we are assuming that most C++ programmers are not (yet) familiar with these new features. We thus provide the following mock API for C++ which is similar to the Java Thread class:

Programming, Java, C++, Concurrency

10 points by LiamPowell 124 days ago | 4 comments

Clojure core.async.flow (github.com/clojure)
The fundamental objective of core.async.flow is to enable a strict separation of your application logic from its topology, execution, communication, lifecycle, monitoring and error handling, all of which are provided by and centralized in, c.a.flow, yielding more consistent, robust, testable, observable and operable systems.

Clojure, Programming Languages, Software Architecture, Concurrency

61 points by cempaka 127 days ago | 3 comments

Show HN: Pyper – Concurrent Python Made Simple (github.com/pyper-dev)
Pyper is a flexible framework for concurrent and parallel data-processing, based on functional programming patterns. Used for 🔀 ETL Systems, ⚙️ Data Microservices, and 🌐 Data Collection

Python, Data Processing, Functional Programming, Concurrency

156 points by pyper-dev 131 days ago | 35 comments

Python Concurrency: Threads, Processes, and Asyncio Explained (newvick.com)
I recently needed to learn Python concurrency. I always thought I’d get to that topic someday. That someday arrived.

Python, Concurrency, Programming, Threads, Asyncio

89 points by BerislavLopac 136 days ago | 28 comments

How concurrency works: A visual guide (wyounas.github.io)
Concurrent programming is hard.

Concurrency, Programming, Visual Guides

170 points by simplegeek 156 days ago | 48 comments