Concurrency

Python LLM applications often start small: a FastAPI route, a call to an LLM provider, some prompt engineering, and you’re done. Then traffic grows, latencies spike, and your CPUs sit mostly idle while users wait seconds—or tens of seconds—for responses. What went wrong? One of the most common and least understood culprits is thread pool starvation. This article explains what thread pool starvation is, why it’s especially dangerous in Python LLM apps, how to detect it, and concrete patterns to avoid or fix it. ...

Threading locks are a fundamental building block for writing correct concurrent programs in Python. Even though Python has the Global Interpreter Lock (GIL), locks in the threading module are still necessary to coordinate access to shared resources, prevent data races, and implement synchronization patterns (producer/consumer, condition waiting, critical sections, etc.). This article is a deep dive into how Python threading locks work: what primitives are available, their semantics and implementation ideas, common usage patterns, pitfalls (deadlocks, starvation, contention), and practical examples demonstrating correct usage. Expect code examples, explanations of the threading API, and guidance for real-world scenarios. ...

Introduction Lazy initialization is a technique where the creation or loading of a resource is deferred until it is actually needed. It’s a simple idea with far-reaching implications: faster startup times, reduced memory footprint, and the ability to postpone costly I/O or network calls. But laziness comes with trade-offs—especially around concurrency, error handling, and observability. When implemented thoughtfully, lazy initialization can significantly improve user experience and system efficiency; when done hastily, it can introduce deadlocks, latency spikes, and subtle bugs. ...

Introduction Asynchronous programming is how we make programs do more than one thing at once without wasting time waiting on slow operations. Whether you’re building responsive web apps, data pipelines, or high-throughput services, “async” is a foundational skill. This zero-to-hero guide gives you a practical mental model, shows idiomatic patterns, walks through language-specific examples, and finishes with a curated list of resources to keep you going. You’ll learn: What async actually is (and isn’t) How it differs from threads and parallelism Real-world patterns like bounded concurrency, cancellation, timeouts, and retries How to implement these patterns in JavaScript/Node.js, Python (asyncio), and C# Testing and performance tips A practical learning path with vetted links Note: Async is a technique for handling latency and concurrency efficiently, commonly for I/O-bound work. CPU-bound tasks require different strategies (e.g., thread pools, processes, or offloading). ...

Introduction Thread pools are a foundational concurrency primitive used to execute units of work (tasks) using a fixed or managed set of threads. They improve performance by amortizing thread lifecycle costs, improve stability by bounding concurrency, and provide operational control via queueing, task rejection, prioritization, and metrics. Despite their ubiquity, thread pools are often misconfigured or misapplied, leading to oversubscription, latency spikes, deadlocks, or underutilization. This comprehensive guide covers how thread pools work, design dimensions and trade-offs, sizing formulas and tuning strategies, scheduling algorithms, instrumentation, and language-specific implementations with code examples. It is aimed at practitioners building high-throughput, low-latency systems, or anyone seeking a deep understanding of thread pool internals and best practices. ...