The blog post argues for a standardized, cross-platform OS API specifically designed for timers. Existing timer mechanisms, like POSIX's timerfd and Windows' CreateWaitableTimer, while useful, differ significantly across operating systems, complicating cross-platform development. The author proposes a new API with a consistent interface that abstracts away these platform-specific details. This ideal API would allow developers to create, arm, and disarm timers, specifying absolute or relative deadlines with optional periodic behavior, all while handling potential issues like early wake-ups gracefully. This would simplify codebases and improve portability for applications relying on precise timing across different operating systems.
Par is a new programming language designed for exploring and understanding concurrency. It features a built-in interactive playground that visualizes program execution, making it easier to grasp complex concurrent behavior. Par's syntax is inspired by Go, emphasizing simplicity and readability. The language utilizes goroutines and channels for concurrency, offering a practical way to learn and experiment with these concepts. While currently focused on concurrency education and experimentation, the project aims to eventually expand into a general-purpose language.
Hacker News users discussed Par's simplicity and suitability for teaching concurrency concepts. Several praised the interactive playground as a valuable tool for visualization and experimentation. Some questioned its practical applications beyond educational purposes, citing limitations compared to established languages like Go. The creator responded to some comments, clarifying design choices and acknowledging potential areas for improvement, such as error handling. There was also a brief discussion about the language's syntax and comparisons to other visual programming tools.
The blog post details how Definite integrated concurrent read/write functionality into DuckDB using Apache Arrow Flight. Previously, DuckDB only supported single-writer, multi-reader access. By leveraging Flight's DoPut and DoGet streams, they enabled multiple clients to simultaneously read and write to a DuckDB database. This involved creating a custom Flight server within DuckDB, utilizing transactions to manage concurrency and ensure data consistency. The post highlights performance improvements achieved through this integration, particularly for analytical workloads involving large datasets, and positions it as a key advancement for interactive data analysis and real-time applications. They open-sourced this integration, making concurrent DuckDB access available to a wider audience.
Hacker News users discussed DuckDB's new concurrent read/write feature via Arrow Flight. Several praised the project's rapid progress and innovative approach. Some questioned the performance implications of using Flight for this purpose, particularly regarding overhead. Others expressed interest in specific use cases, such as combining DuckDB with other data tools and querying across distributed datasets. The potential for improved performance with columnar data compared to row-based systems was also highlighted. A few users sought clarification on technical aspects, like the level of concurrency achieved and how it compares to other databases.
The article "The Mythical IO-Bound Rails App" argues that the common belief that Rails applications are primarily I/O-bound, and thus not significantly impacted by CPU performance, is a misconception. While database queries and external API calls contribute to I/O wait times, a substantial portion of a request's lifecycle is spent on CPU-bound activities within the Rails application itself. This includes things like serialization/deserialization, template rendering, and application logic. Optimizing these CPU-bound operations can significantly improve performance, even in applications perceived as I/O-bound. The author demonstrates this through profiling and benchmarking, showing that seemingly small optimizations in code can lead to substantial performance gains. Therefore, focusing solely on database or I/O optimization can be a suboptimal strategy; CPU profiling and optimization should also be a priority for achieving optimal Rails application performance.
Hacker News users generally agreed with the article's premise that Rails apps are often CPU-bound rather than I/O-bound, with many sharing anecdotes from their own experiences. Several commenters highlighted the impact of ActiveRecord and Ruby's object allocation overhead on performance. Some discussed the benefits of using tools like rack-mini-profiler and flamegraphs for identifying performance bottlenecks. Others mentioned alternative approaches like using different Ruby implementations (e.g., JRuby) or exploring other frameworks. A recurring theme was the importance of profiling and measuring before optimizing, with skepticism expressed towards premature optimization for perceived I/O bottlenecks. Some users questioned the representativeness of the author's benchmarks, particularly the use of SQLite, while others emphasized that the article's message remains valuable regardless of the specific examples.
Scaling WebSockets presents challenges beyond simply scaling HTTP. While horizontal scaling with multiple WebSocket servers seems straightforward, managing client connections and message routing introduces significant complexity. A central message broker becomes necessary to distribute messages across servers, introducing potential single points of failure and performance bottlenecks. Various approaches exist, including sticky sessions, which bind clients to specific servers, and distributing connections across servers with a router and shared state, each with tradeoffs. Ultimately, choosing the right architecture requires careful consideration of factors like message frequency, connection duration, and the need for features like message ordering and guaranteed delivery. The more sophisticated the features and higher the performance requirements, the more complex the solution becomes, involving techniques like sharding and clustering the message broker.
HN commenters discuss the challenges of scaling WebSockets, agreeing with the article's premise. Some highlight the added complexity compared to HTTP, particularly around state management and horizontal scaling. Specific issues mentioned include sticky sessions, message ordering, and dealing with backpressure. Several commenters share personal experiences and anecdotes about WebSocket scaling difficulties, reinforcing the points made in the article. A few suggest alternative approaches like server-sent events (SSE) for simpler use cases, while others recommend specific technologies or architectural patterns for robust WebSocket deployments. The difficulty in finding experienced WebSocket developers is also touched upon.
The author argues that Go's context.Context is overused and often misused as a dumping ground for arbitrary values, leading to unclear dependencies and difficult-to-test code. Instead of propagating values through Context, they propose using explicit function parameters, promoting clearer code, better separation of concerns, and easier testability. They contend that using Context primarily for cancellation and timeouts, its intended purpose, would streamline code and improve its maintainability.
HN commenters largely agree with the author's premise that context.Context in Go is overused and often misused for dependency injection or as a dumping ground for miscellaneous values. Several suggest that structured concurrency, improved error handling, and better language features for cancellation and deadlines could alleviate the need for context in many cases. Some argue that context is still useful for request-scoped values, especially in server contexts, and shouldn't be entirely removed. A few commenters express concern about the practicality of removing context given its widespread adoption and integration into the standard library. There is a strong desire for better alternatives, rather than simply discarding the existing mechanism without a replacement. Several commenters also mention the similarities between context overuse in Go and similar issues with dependency injection frameworks in other languages.
Pyper simplifies concurrent programming in Python by providing an intuitive, decorator-based API. It leverages the power of asyncio without requiring explicit async/await syntax or complex event loop management. By simply decorating functions with @pyper.task, they become concurrently executable tasks. Pyper handles task scheduling and execution transparently, making it easier to write performant, concurrent code without the typical asyncio boilerplate. This approach aims to improve developer productivity and code readability when dealing with concurrency.
Hacker News users generally expressed interest in Pyper, praising its simplified approach to concurrency in Python. Several commenters compared it favorably to existing solutions like multiprocessing and Ray, highlighting its ease of use and seemingly lower overhead. Some questioned its performance characteristics compared to more established libraries, and a few pointed out potential limitations or areas for improvement, such as handling large data transfers between processes and clarifying the licensing situation. The discussion also touched upon potential use cases, including simplifying parallelization in scientific computing. Overall, the reception was positive, with many commenters eager to try Pyper in their own projects.
This paper demonstrates how seemingly harmless data races in C/C++ programs, specifically involving non-atomic operations on padding bytes, can lead to miscompilation by optimizing compilers. The authors show that compilers can exploit the assumption of data-race freedom to perform transformations that change program behavior when races are actually present. They provide concrete examples where races on padding bytes within structures cause compilers like GCC and Clang to generate incorrect code, leading to unexpected outputs or crashes. This highlights the subtle ways in which undefined behavior due to data races can manifest, even when the races appear to involve data irrelevant to program logic. Ultimately, the paper reinforces the importance of avoiding data races entirely, even those that might seem benign, to ensure predictable program behavior.
Hacker News users discussed the implications of Boehm's paper on benign data races. Several commenters pointed out the difficulty in truly defining "benign," as seemingly harmless races can lead to unexpected behavior in complex systems, especially with compiler optimizations. Some highlighted the importance of tools and methodologies to detect and prevent data races, even if deemed benign. One commenter questioned the practical applicability of the paper's proposed relaxed memory model, expressing concern that relying on "benign" races would make debugging significantly harder. Others focused on the performance implications, suggesting that allowing benign races could offer speed improvements but might not be worth the potential instability. The overall sentiment leans towards caution regarding the exploitation of benign data races, despite acknowledging the potential benefits.
The article explores a new method for process creation using io_uring, aiming to improve efficiency and reduce overhead compared to traditional fork() and execve(). This new approach uses a "registered executable" within io_uring, allowing asynchronous process launching without the performance penalties of copying memory pages between parent and child processes. The proposed solution involves two new system calls: pidfd_spawn() and pidfd_wait(). pidfd_spawn() creates a new process from the registered executable and returns a process file descriptor, while pidfd_wait() provides an asynchronous wait mechanism using io_uring. This approach offers a streamlined process-creation pathway within the io_uring framework, potentially boosting performance for applications that frequently spawn processes, like containers or web servers.
Hacker News users discuss the implications of io_uring's new process creation capabilities. Several express excitement about the potential performance improvements, particularly for applications that frequently spawn processes, like web servers. Some highlight the security benefits of avoiding execve, while others raise concerns about the complexity introduced by this new feature and the potential for misuse. A few commenters delve into the technical details, comparing the approach to other process creation methods and discussing the trade-offs involved. Several anticipate interesting use cases, including containerization and sandboxing. One user questions if io_uring is becoming overly complex and straying from its original purpose.
Summary of Comments ( 18 )
https://news.ycombinator.com/item?id=42915437
The Hacker News comments discuss the complexities of cross-platform timer APIs, largely agreeing with the article's premise. Several commenters highlight the difficulties introduced by different operating systems' power management features, impacting timer accuracy and reliability. Specific challenges like signal coalescing and the lack of a unified interface for monotonic timers are mentioned. Some propose workarounds like busy-waiting for short durations or using platform-specific code for optimal performance. The need for a standardized API is reiterated, with suggestions for what such an API should offer, including considerations for power efficiency and different timer resolutions. One commenter points to the challenges of abstracting away hardware differences completely, suggesting the ideal solution may involve a combination of OS-level improvements and application-specific strategies.
The Hacker News post "The missing cross-platform OS API for timers" generated several comments discussing the challenges and nuances of timer implementations across different operating systems.
Several commenters highlighted the inherent difficulties in creating a truly cross-platform timer API due to the varying underlying mechanisms and priorities of each OS. One user pointed out the complexities introduced by power management, specifically how different systems handle timers during sleep or low-power states. This difference in behavior makes it difficult to abstract away the platform-specific details into a unified API. Another commenter echoed this sentiment, emphasizing that timers are often deeply integrated with the OS scheduler and power management, making a universal solution challenging. They also pointed to the trade-off between accuracy and power efficiency, which further complicates a cross-platform approach.
The discussion also touched on the existing solutions and their limitations. One comment mentioned
kqueueon macOS/BSD platforms and epoll on Linux, acknowledging their suitability for event-driven programming but also their lack of a direct cross-platform equivalent. The lack of a unified interface across these different mechanisms was reiterated by another commenter who emphasized the need to deal with distinct APIs and behaviors on each platform.Some commenters delved into specific use cases and challenges, such as dealing with high-resolution timers and the limitations imposed by system clock granularity. One commenter discussed the difficulties in achieving precise timing in JavaScript, citing the impact of browser event loops and garbage collection.
The complexities of timer coalescing were also brought up. One commenter explained how operating systems might group timer events to reduce CPU wakeups and improve power efficiency, which can affect the precision of timer execution. Another commenter noted that this behavior can be unpredictable and difficult to account for in a cross-platform API.
Finally, a few comments explored alternative approaches, like using a dedicated thread for timer management, although this was acknowledged as potentially resource-intensive. The discussion ultimately highlighted the significant challenges in designing a truly cross-platform timer API, with the conclusion being that a "one-size-fits-all" solution might not be feasible due to the inherent differences in OS architectures and priorities.