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Kernel: Threading, Streebog, USB 3.0, "Thermal Pressure" and More

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Linux
  • A Look At Linux Application Scaling Up To 128 Threads

    Arriving last week in our Linux benchmarking lab was a dual EPYC server -- this Dell PowerEdge R7425 is a beast of a system with two AMD EPYC 7601 processors yielding a combined 64 cores / 128 threads, 512GB of RAM (16 x 32GB DDR4), and 20 x 500GB Samsung 860 EVO SSDs. There will be many interesting benchmarks from this server in the days and weeks ahead. For some initial measurements during the first few days of stress testing this 2U rack server, here is a look at how well various benchmarks/applications are scaling from two to 128 threads.

  • Linux Kernel Patches Posted For Streebog - Crypto From Russia's FSB

    Just months after the controversial Speck crypto code was added to the Linux kernel that raised various concerns due to its development by the NSA and potential backdoors, which was then removed from the kernel tree, there is now Russia's Streebog that could be mainlined.

    The Streebog cryptographic hash was developed by Russia's controversial FSB federal security service and other Russian organizations. Streebog is a Russian national standard and a replacement to their GOST hash function. Streebog doesn't have as much controversy as NSA's Speck, but then again it's not as well known but there is are some hypothetical attacks and some papers have questioned some elements of the design. Streebog is considered to be a competitor to the SHA-3 standard from the NIST.

  • The Linux Kernel In 2018 Finally Deems USB 3.0 Ubiquitous Rather Than An Oddity

    The latest news in the "it's about darn time" section is the Linux kernel's default i386/x86_64 kernel configurations will finally ship with USB 3.0 support enabled, a.k.a. CONFIG_USB_XHCI_HCD.

    For many years now pretty much all Linux distribution vendor kernels have been shipping with CONFIG_USB_XHCI_HCD enabled either built-in or as a module... But built-in is pretty much the best to avoid potential issues at start-up time. As of this week, CONFIG_USB_XHCI_HCD=y is finally set for the default configurations on the x86/x86_64-based kernel builds should you be spinning up a defconfig kernel.

  • "Thermal Pressure" Kernel Feature Would Help Linux Performance When Running Hot

    Linaro engineer Thara Gopinath sent out an experimental set of kernel patches today that introduces the concept of "thermal pressure" to the Linux kernel for helping assist Linux performance when the processor cores are running hot.

    While the Linux CPU frequency scaling code already deals with the event of CPU core(s) overheating as to downclock/limit the frequency, the kernel's scheduler isn't currently aware of the CPU capacity restrictions put in place due to that thermal event.

  • Containers are Linux

    Linux is the core of today’s operating system open source software development, and containers are a core feature of Linux. Linux containers and the Kubernetes community supporting them enable agencies to quickly stand up, distribute and scale applications in the hybrid clouds supporting the IT architecture of today’s digitally transformed government.

    But agencies need more than the speed and flexibility of containers and the power of Kubernetes to take full advantage of today’s hybrid cloud environment. They need open source enterprise software with full lifecycle support and a full complement of hardware certifications to ensure portability across platforms.

More in Tux Machines

Raspbian Linux distribution updated, but with one unexpected omission

Those last two are the ones that really produced some excitement in the Raspberry Pi community. Just look at that next to last one... so innocent looking... but then go and look at the discussion in the Pi Forums about it. For those who might not be familiar with it, Mathematica (and the Wolfram language) is a technical computing system that is very widely used in both education and industry. It has been included on the Raspberry Pi since the beginning, and when you consider that a normal "desktop" license costs €160 for a "student", or €345 for "home and hobby", it's an exceptionally good deal to get it for free with a $35 Raspberry Pi. That makes it a bit easier to understand why some users would be upset about it being removed. Read more

Games: Kingdom Rush Origins, Jackbox Games, Gaming on the Latest Ubuntu

2nd New MakuluLinux Release Offers Flash and Substance

The MakuluLinux Flash distro is splashy and fast with a spiffy new look and new features. MakuluLinux developer Jacque Montague Raymer on Thursday announced the second of this year's three major releases in the Series 15 distro family. The Flash edition follows last month's LinDoz edition release. The much-awaited innovative Core edition will debut between the end of November and mid-December. MakuluLinux is a relatively new Linux OS. Its positive reputation has been developing since 2015. The three-year growth spurt involved a variety of desktop environments. Its small developer team has delivered a surprisingly efficient and productive desktop distribution in a relatively short time period. It is unusual to see a startup rise so quickly to offer an innovative and highly competitive computing platform. Series 15 is not an update of last year's editions. This latest release introduces some radical changes that were under development for the last two years. The Series 15 releases of LinDoz and Flash include a complete rip-and-replace rebuild on top of an in-house developed computing base. LinDoz and Flash have been reworked completely from the ground up. Read more

Kernel: LWN Linux Articles Now Outside the Paywall

  • What's a CPU to do when it has nothing to do?
    It would be reasonable to expect doing nothing to be an easy, simple task for a kernel, but it isn't. At Kernel Recipes 2018, Rafael Wysocki discussed what CPUs do when they don't have anything to do, how the kernel handles this, problems inherent in the current strategy, and how his recent rework of the kernel's idle loop has improved power consumption on systems that aren't doing anything. The idle loop, one of the kernel subsystems that Wysocki maintains, controls what a CPU does when it has no processes to run. Precise to a fault, Wysocki defined his terms: for the purposes of this discussion, a CPU is an entity that can take instructions from memory and execute them at the same time as any other entities in the same system are doing likewise. On a simple, single-core single-processor system, that core is the CPU. If the processor has multiple cores, each of those cores is a CPU. If each of those cores exposes multiple interfaces for simultaneous instruction execution, which Intel calls "hyperthreading", then each of those threads is a CPU.
  • New AT_ flags for restricting pathname lookup
    System calls like openat() have access to the entire filesystem — or, at least, that part of the filesystem that exists in the current mount namespace and which the caller has the permission to access. There are times, though, when it is desirable to reduce that access, usually for reasons of security; that has proved to be especially true in many container use cases. A new patch set from Aleksa Sarai has revived an old idea: provide a set of AT_ flags that can be used to control the scope of a given pathname lookup operation. There have been previous attempts at restricting pathname lookup, but none of them have been merged thus far. David Drysdale posted an O_BENEATH option to openat() in 2014 that would require the eventual target to be underneath the starting directory (as provided to openat()) in the filesystem hierarchy. More recently, Al Viro suggested AT_NO_JUMPS as a way of preventing lookups from venturing outside of the current directory hierarchy or the starting directory's mount point. Both ideas have attracted interest, but neither has yet been pushed long or hard enough to make it into the mainline.
  • Some numbers from the 4.19 development cycle
    The release of 4.19-rc6 on September 30 is an indication that the 4.19 development cycle is heading toward its conclusion. Naturally, that means it's time to have a look at where the contributions for this cycle came from. The upheavals currently playing out in the kernel community do not show at this level, but there are some new faces to be seen in the top contributors this time around. As of this writing, 13,657 non-merge changesets have found their way into the mainline for 4.19.
  • The modernization of PCIe hotplug in Linux
    PCI Express hotplug has been supported in Linux for fourteen years. The code, which is aging, is currently undergoing a transformation to fit the needs of contemporary applications such as hot-swappable flash drives in data centers and power-manageable Thunderbolt controllers in laptops. Time for a roundup. The initial PCI specification from 1992 had no provisions for the addition or removal of cards at runtime. In the late 1990s and early 2000s, various proprietary hotplug controllers, as well as the vendor-neutral standard hotplug controller, were conceived and became supported by Linux through drivers living in drivers/pci/hotplug. PCI Express (PCIe), instead, supported hotplug from the get-go in 2002, but its embodiments have changed over time. Originally intended to hot-swap PCIe cards in servers or ExpressCards in laptops, today it is commonly used in data centers (where NVMe flash drives need to be swapped at runtime) and by Thunderbolt (which tunnels PCIe through a hotpluggable chain of converged I/O switches, together with other protocols such as DisplayPort).