Why 'free -h' Lies: A Developer's Deep Dive into Linux Memory Metrics

·1 views

Developer Maneshwar, while building a terminal system monitor using Rust and the ratatui library, discovered that Linux's MemFree metric is widely misunderstood and nearly always misleadingly low. The Linux kernel intentionally fills spare RAM with page cache to maximise efficiency, meaning MemFree trends toward zero on a healthy system — not a struggling one. The correct metric to read is MemAvailable, introduced in kernel version 3.14 specifically because so many tools and users were misreading MemFree. Maneshwar also uncovered a subtle parsing bug in /proc/meminfo, where the field SwapCached can silently overwrite the Cached value if labels are matched loosely rather than exactly. He adopted btop's simpler formula — used equals MemTotal minus MemAvailable — and added a dedicated unit test to prevent future regressions in the parser.

Read the full story at DEV Community

This is an AI-generated summary. ShortSingh links to the original source for the complete article.

Discussion (0)

Developer Builds LLM Trading Bot After Reading 77 Research Papers

A developer based in Wrocław, Poland spent late 2024 building an AI-powered trading bot after repeated failures using conventional LLM prompt-based approaches found in online tutorials. Instead of feeding raw numbers to a language model, he shifted to visual inference by sending 4K candlestick charts with five technical indicators directly to Google Gemini for pattern analysis. After testing his own hand-coded pattern detection algorithms against the AI's visual reads, he found the AI significantly outperformed his code, leading him to delete 900 lines of custom logic. He built a full indicator engine from scratch using NumPy and Numba, compiling over 50 technical indicators to machine code for microsecond-level performance on a standard desktop CPU. The bot uses a single structured prompt that requires the model to argue both bullish and bearish cases before reaching a decision, reducing API costs compared to multi-agent frameworks.

0 comments Read more at DEV Community

ProgrammingDEV Community ·

How Real-World Experience Helps Technical Writing Stand Out in the AI Content Era

The rise of AI-generated content has made generic technical writing nearly obsolete, as average posts can now be replicated by language models in seconds. Writers are advised to anchor their content in real experience and specific friction points — such as a duplicate payout incident — rather than textbook definitions. Effective technical posts should function as decision-support tools, helping readers answer practical questions about adopting tools or solving problems under real constraints. Experts suggest writing narrower, opinionated content over exhaustive 'complete guides,' since useful reduction is harder for AI to replicate than broad summaries. Originality in technical writing, the article argues, comes from honest pattern recognition built over years of hands-on work, not from revolutionary theories.

0 comments Read more at DEV Community

ProgrammingDEV Community ·

DSA Challenge: Generate Uniform Random Numbers Using a Binary Generator

A developer has shared a data structures and algorithms problem sourced from the book 'Elements of Programming Interviews in Java' by Lee, Aziz, and Prakash. The challenge, listed as problem 4.10, asks how to generate a uniformly random integer between two values, a and b inclusive, using only a binary random generator that returns 0 or 1 with equal probability. A hint accompanying the problem draws an analogy to simulating a three-sided coin using a two-sided coin. The post also nudges solvers to consider what the expression b minus a represents and how it can help minimize calls to the generator. This is the author's first post on the platform, with plans to share more interesting DSA and interview-style problems in the future.

0 comments Read more at DEV Community

ProgrammingDEV Community ·

Developer Builds Glassmorphism Comfort Food Landing Page for Frontend Challenge

A developer created 'Cantina de Casa', a comfort food-themed landing page as a submission for the DEV Community Frontend Challenge - Comfort Food Edition. The page showcases classic home-cooked dishes such as Feijoada, Grandma's Pasta, and Chicken with Okra, each with pricing and order options. The design prioritizes clean, intuitive navigation using a glassmorphism aesthetic built with modern CSS variables and a standardized dm_ class prefix for scoped, organized code. The goal was not complexity but usability, ensuring visitors can find information without confusion. A live demo and the full codebase were shared publicly for others to explore or run locally.

0 comments Read more at DEV Community