Posts

Background: when you’re subscribed to multiple mailing lists like the Linux Kernel Mailing List (lkml), bpf, dwarves, io-uring, linux-embedded, and others, the daily flood of emails makes it impossible to read everything in detail. Still, I want to keep up with ongoing development. That’s why I built a ChatGPT Summary Generator that integrates nicely with my OfflineIMAP–NeoMutt–Notmuch setup. Sorry for the clickbait — it’s just an email-to-ChatGPT fan-out. No proprietary Google/Microsoft stuff involved....

This blog-post demostrate how Intel Processor Trace (PT) can be usable for everyday reverse-engineering and debugging tasks by showing exactly how to capture and decode real execution, not just what the program could do in theory. PT is powerful and surprisingly underused; once you see how to drive it with perf, it becomes a reliable way to cut through indirection, obfuscation, and environment-dependent behavior. Agenda We start with core notions of control-flow analysis, move to what Intel PT actually records, then work through a practical perf workflow, deal with common pitfalls, and close with limits and an appendix on correlating addresses under ASLR....

Banana Pi F3 Christmas project: I got a Banana Pi F3 on the cheap and used the quiet hours to power it up, take inventory, and write a technical first look. This post is deliberately terse and focused on what matters to Linux developers and performance engineers. TL;DR: Octa-core 64-bit RISC-V with RVV 1.0 (256-bit), two coherent clusters, sensible caches, usable PCIe and I/O. Treat the GPU and video items as hardware capability; the Linux userspace stacks may lag....

tl;dr: for 25 years standard vim user, without plugins. Since two years questioned bad habits and analyzed repetitive pattern and switched to neovim with certain plugin set. Here I describe which plugins I use and why. Before I go into detail, I would like to explain my working practices in this section. This is important because my setup is tailored to my environment and may be completely different for you. Admittedly, I don’t get to do much programming....

After a period of inactivity (~11 years now, with the exception of 2 posts, 7 years ago) in managing my website, it became clear that an upgrade to my web infrastructure was essential. Due to outdated scripts and other technical challenges, I’ve opted for a comprehensive overhaul of my web hosting solutions. Consequently, I am transitioning from Jekyll and Google Hosting to adopting Hugo, in combination with Cloudflare, for a more robust and updated online presence....

From time to time students ask me for book recommendations. Subsequently my personal top five(+/-) lists for each category (a little bit Linux (kernel) and C biased). I believe these are the books you should read when you are interested in one particular topic: Computer Architecture Processor Microarchitecture: An Implementation Perspective; Antonio Gonzalez and Fernando Latorre and Grigorios Magklis; The title says it all! A book you should probably read after you read all other books in this section....

Introduction First off all: this guide is no replacement for the great OpenWrt documentation. Rather this guide show what software I use and how I configure the system. Sure, some software components smells fishy, the hardware could be better and so on. But this setup is great and fullfills my requirements and at least do not use any proprietary components like FritzBox (who want’s closed source in the private network? Do they backport all kernel bugfixes?...

Memory latency and bandwidth is one major performance factor. I once visualized all memory subsystems and their latency impact of my Xeon 5500 in a illustration.

I track some Linux kernel development subsystems: Linus, perf, network (davem’s) net-next and lkvm. Additionally I add two historic Linux repositories: Thomas post 2.4 tree and davej’s pre 2.4 branch. In the earlier git days I referenced cloned locally. Later I started to add remotes within one repository. To setup this environment the following commands may be helpful: # create a vanilla git container mkdir linux; cd linux git init # add remotes git remote add --track torvalds git://git....

Today some ideas how Captcp generated throughput graphs can be modified and improved. We start with a pcap file (captured via tcpdump or wireshark). We create a output directory, called graphs and finally start captcp and visualize one TCP flow. The number of the connection and flow (-f 45.2) is a result of captcp’s statistic module - I just picked up one random flow within the capture file. The output of captcp is saved in the directory graphs....