It has been a really long time since I last wrote something here as life happens, things get busier, etc etc. I am now trying to get back into writing things down and here we go! So, imagine a tool or a service that allows you to run some arbitrary code via a shell. Either through a ssh or more commonly, via a web…
I’ve been working on a CLI tool recently, and one of the things it does is manage files on disk. I have written a lot of file management tests for Bundler, and the two biggest reasons that the Bundler test suite is slow are exec and fstat. Knowing that, I thought I would try to get out ahead of the slow file stat…
In preparation for a future project, I was thinking about at the unix find utility . It operates a file system hierarchies, with basic operations selected and filtered using a specialized expression language. Users compose operations using unary and binary operators, grouping with parentheses for precedence. find may…
Ultrassembler is a superfast and complete RISC-V assembler library that I'm writing as a component of the bigger Chata signal processing project.
ETH Zürich’s new VMScape attack hit KVM and VMware, but Xen’s microkernel-like design kept it out of reach.
So you don't have to.
20 years of Linux on the Desktop (part 4) par Ploum - Lionel Dricot.
1.0 The Silicon Root of Trust: Pre-Boot & Hardware Primitives The security of the macOS platform on Apple Silicon is not defined by the kernel; it is d...
A 1987 technical introduction to OS/2, covering its architecture, multitasking capabilities, API, and kernel system services.
Just wondering how many transactions or writes per second MySQL can handle? While it depends on many factors, fundamentally, about as many transactions as MySQL can commit to disk per second. A modern disk can do ~1000 fsyncs per second , but MySQL will group multiple writes with each fsync. An okay rule-of-thumb…
This is a follow-up to making the rav1d video decoder 1% faster, where we compared profiler snapshots of rav1d (the Rust implementation) and dav1d (the C …
Is 1970s distributed systems theory finally meeting 2020s kernel development?
We’ve discussed SIMD and vectorization extensively on this blog, and it was only a matter of time before SIMD (or vector) functions came up. In this post, we explore what SIMD functions are, when they are useful, and how to declare and use them effectively. A SIMD function is a function that processes more than… Read
I built a simple web crawler using good old platform threads. It was just a multithreaded crawler, nothing fancy. But then, curiosity…
Json parsing in C using function pointers attached to a struct
Both GCC and Clang support the -fsanitize=undefined flag which instruments the generated code to detect places where the program wanders into parts of the C language specification which are either undefined or implementation defined. Many of these are also common programming errors. It would be great if there were…
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Writing Super-Fast Matrix Multiplication with HIP, RGP, and ISA
Every field of human activity has its unique characteristics, and programming is no exception.
I recently tried using the Minisforum DEG1 GPU Dock with a Raspberry Pi 500+, using an M.2 to OCuLink adapter, and this chenyang SFF-8611 Cable. After figuring out there's a power button on the DEG1 (which needs to be turned on), and after fiddling around with the switches on the PCB (hidden under the large metal…
meshoptimizer implements several geometry compression algorithms that are designed to take advantage of redundancies common in mesh data and decompress quickly - targeting many gigabytes per second in decoding throughput. One of them, index decoder, has seen a significant and unexpected variance in performance across…
You're probably reading this page because you've attempted to access some part of my blog (Wandering Thoughts) or CSpace , the wiki thing it's part of. Unfortunately you're using a browser version that my anti-crawler precautions consider suspicious, most often because it's too old (most often this applies to versions…
I’d like to talk more about a container technology that I really like that I touched upon in a previous article : systemd-nspawn .
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In this blog post, we walk through how to use Matrix Cores in HIP kernels, with a focus on low-precision data types such as FP16, FP8, and FP4, as well as the new family of Matrix Core instructions with exponent block scaling introduced in the AMD CDNA™4 architecture. Through code examples and illustrations, we…
While not an absolute requirement for modern graphics card support on Linux, Resizeable BAR support makes GPUs go faster, by allowing GPUs to throw data back and forth on the PCIe bus in chunks larger than 256 MB. In January, I opened an issue in the Raspberry Pi Linux repo, Resizable BAR support on Pi 5. Unlike most…
At Terrateam, we are big fans of Fly.io. The service is hosted there and it’s served us well. Just deploy your TOML file, get your infrastructure, do something else with the rest of your day. One of the interesting sides of Fly is that they invest heavily in server-side SQLite. They’ve written a number of blog posts…
You may know that, because your computer has different caches (L1, L2, L3...), and memory operations operate on cache lines of about 64 bytes each, you should write programs that exhibit locality to get maximum performance.
