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Kernel: RNG, Networking, and More

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Linux
  • Uniting the Linux random-number devices [LWN.net]

    Blocking in the kernel's random-number generator (RNG)—causing a process to wait for "enough" entropy to generate strong random numbers—has always been controversial. It has also led to various kinds of problems over the years, from timeouts and delays caused by misuse in user-space programs to deadlocks and other problems in the boot process. That behavior has undergone a number of changes over the last few years and it looks possible that the last vestige of the difference between merely "good" and "cryptographic-strength" random numbers may go away in some upcoming kernel version.

  • Going big with TCP packets [LWN.net]

    Like most components in the computing landscape, networking hardware has grown steadily faster over time. Indeed, today's high-end network interfaces can often move data more quickly than the systems they are attached to can handle. The networking developers have been working for years to increase the scalability of their subsystem; one of the current projects is the BIG TCP patch set from Eric Dumazet and Coco Li. BIG TCP isn't for everybody, but it has the potential to significantly improve networking performance in some settings.

    Imagine, for a second, that you are trying to keep up with a 100Gb/s network adapter. As networking developer Jesper Brouer described back in 2015, if one is using the longstanding maximum packet size of 1,538 bytes, running the interface at full speed means coping with over eight-million packets per second. At that rate, CPU has all of about 120ns to do whatever is required to handle each packet, which is not a lot of time; a single cache miss can ruin the entire processing-time budget.

    The situation gets better, though, if the number of packets is reduced, and that can be achieved by making packets larger. So it is unsurprising that high-performance networking installations, especially local-area networks where everything is managed as a single unit, use larger packet sizes. With proper configuration, packet sizes up to 64KB can be used, improving the situation considerably. But, in settings where data is being moved in units of megabytes or gigabytes (or more — cat videos are getting larger all the time), that still leaves the system with a lot of packets to handle.

    Packet counts hurt in a number of ways. There is a significant fixed overhead associated with every packet transiting a system. Each packet must find its way through the network stack, from the upper protocol layers down to the device driver for the interface (or back). More packets means more interrupts from the network adapter. The sk_buff structure ("SKB") used to represent packets within the kernel is a large beast, since it must be able to support just about any networking feature that may be in use; that leads to significant per-packet memory use and memory-management costs. So there are good reasons to wish for the ability to move data in fewer, larger packets, at least for some types of applications.

  • Remote per-CPU page list draining [LWN.net]

    Sometimes, a kernel-patch series comes with an exciting, sexy title. Other times, the mailing lists are full of patches with titles like "remote per-cpu lists drain support". For many, the patches associated with that title will be just as dry as the title itself. But, for those who are interested in such things — a group that includes many LWN readers — this short patch series from Nicolas Saenz Julienne gives some insight into just what is required to make the kernel's page allocator as fast — and as robust — as developers can make it.

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Dilution and Misuse of the "Linux" Brand

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today's howtos

  • How to install go1.19beta on Ubuntu 22.04 – NextGenTips

    In this tutorial, we are going to explore how to install go on Ubuntu 22.04 Golang is an open-source programming language that is easy to learn and use. It is built-in concurrency and has a robust standard library. It is reliable, builds fast, and efficient software that scales fast. Its concurrency mechanisms make it easy to write programs that get the most out of multicore and networked machines, while its novel-type systems enable flexible and modular program constructions. Go compiles quickly to machine code and has the convenience of garbage collection and the power of run-time reflection. In this guide, we are going to learn how to install golang 1.19beta on Ubuntu 22.04. Go 1.19beta1 is not yet released. There is so much work in progress with all the documentation.

  • molecule test: failed to connect to bus in systemd container - openQA bites

    Ansible Molecule is a project to help you test your ansible roles. I’m using molecule for automatically testing the ansible roles of geekoops.

  • How To Install MongoDB on AlmaLinux 9 - idroot

    In this tutorial, we will show you how to install MongoDB on AlmaLinux 9. For those of you who didn’t know, MongoDB is a high-performance, highly scalable document-oriented NoSQL database. Unlike in SQL databases where data is stored in rows and columns inside tables, in MongoDB, data is structured in JSON-like format inside records which are referred to as documents. The open-source attribute of MongoDB as a database software makes it an ideal candidate for almost any database-related project. This article assumes you have at least basic knowledge of Linux, know how to use the shell, and most importantly, you host your site on your own VPS. The installation is quite simple and assumes you are running in the root account, if not you may need to add ‘sudo‘ to the commands to get root privileges. I will show you the step-by-step installation of the MongoDB NoSQL database on AlmaLinux 9. You can follow the same instructions for CentOS and Rocky Linux.

  • An introduction (and how-to) to Plugin Loader for the Steam Deck. - Invidious
  • Self-host a Ghost Blog With Traefik

    Ghost is a very popular open-source content management system. Started as an alternative to WordPress and it went on to become an alternative to Substack by focusing on membership and newsletter. The creators of Ghost offer managed Pro hosting but it may not fit everyone's budget. Alternatively, you can self-host it on your own cloud servers. On Linux handbook, we already have a guide on deploying Ghost with Docker in a reverse proxy setup. Instead of Ngnix reverse proxy, you can also use another software called Traefik with Docker. It is a popular open-source cloud-native application proxy, API Gateway, Edge-router, and more. I use Traefik to secure my websites using an SSL certificate obtained from Let's Encrypt. Once deployed, Traefik can automatically manage your certificates and their renewals. In this tutorial, I'll share the necessary steps for deploying a Ghost blog with Docker and Traefik.