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Kernel: Wayland, NVIDIA and Linux Development (LWN)

Filed under
Graphics/Benchmarks
Linux
  • Problems Being Investigated Under Wayland Itches Program, Including Gaming Performance

    Last week we wrote about a "Wayland Itches" program being devised by prolific open-source contributor Hans de Goede of Red Hat. The goal of this program is to address itches/paper-cuts/problems in using GNOME Shell atop Wayland. He's received a fair amount of feedback so far and has some early indications to share.

    Hans de Goede wrote two blog posts today outlining the early feedback to his Wayland Itches project. Two items he is going to look into initially are middle-click on title/header bar to lower the Window not working for native applications and sudo/pfexec not working on Wayland. For the sudo/pfexec support, Hans is planning to optionally support the ability for GUI apps to connect when running as root. That was rejected upstream before but his plan is for this to be an optional feature for enabling the xauth file for allowing XWayland as root by GNOME-Shell/Mutter.

  • NVIDIA 418.52.07 Linux Driver Wires In Two More Extensions

    NVIDIA today released the 418.52.07 Linux driver as an updated build intended for Vulkan developers with it introducing support for two more extensions.

  • BPF: what's good, what's coming, and what's needed

    The 2019 Linux Storage, Filesystem, and Memory-Management Summit differed somewhat from its predecessors in that it contained a fourth track dedicated to the BPF virtual machine. LWN was unable to attend most of those sessions, but a couple of BPF-related talks were a part of the broader program. Among those was a plenary talk by Dave Miller, described as "a wholistic view" of why BPF is successful, its current state, and where things are going.

    Years ago, Miller began, Alexei Starovoitov showed up at a netfilter conference promoting his ideas for extending BPF. He described how it could be used to efficiently implement various types of switching fabric — any type, in fact. Miller said that he didn't understand the power of this idea until quite a bit later.

  • The first half of the 5.2 merge window

    When he released the 5.1 kernel, Linus Torvalds noted that he had a family event happening in the middle of the 5.2 merge window and that he would be offline for a few days in the middle. He appears to be trying to make up for lost time before it happens: over 8,300 non-merge changesets have found their way into the mainline in the first four days. As always, there is a wide variety of work happening all over the kernel tree.

  • DAX semantics

    In the filesystems track at the 2019 Linux Storage, Filesystem, and Memory-Management Summit, Ted Ts'o led a discussion about an inode flag to indicate DAX files, which is meant to be applied to files that should be directly accessed without going through the page cache. XFS has such a flag, but ext4 and other filesystems do not. The semantics of what the flag would mean are not clear to Ts'o (and probably others), so the intent of the discussion was to try to nail those down.

    Dan Williams said that the XFS DAX flag is silently ignored if the device is not DAX capable. Otherwise, the file must be accessed with DAX. Ts'o said there are lots of questions about what turning on or off a DAX flag might mean; does it matter whether there are already pages in the page cache, for example. He said that he did not have any strong preference but thought that all filesystems should stick with one interpretation.

    While Christoph Hellwig described things as "all broken", Ts'o was hoping that some agreement could be reached among the disparate ideas of what a DAX flag would mean. A few people think there should be no flag and that it should all be determined automatically, but most think the flag is useful. He suggested starting with something "super conservative", such as only being able to set the flag for zero-length files or only empty directories where the files in it would inherit the flag. Those constraints could be relaxed later if there was a need.

  • A filesystem for virtualization

    A new filesystem aimed at sharing host filesystems with KVM guests, virtio-fs, was the topic of a session led by Miklos Szeredi at the 2019 Linux Storage, Filesystem, and Memory-Management Summit. The existing solution, which is based on the 9P filesystem from Plan 9, has some shortcomings, he said. Virtio-fs is a prototype that uses the Filesystem in Userspace (FUSE) interface.

    The existing 9P-based filesystem does not provide local filesystem semantics and is "pretty slow", Szeredi said. The FUSE-based virtio-fs (RFC patches) is performing "much better". One of the ideas behind the new filesystem is to share the page cache between the host and guests, so there would be no data duplication for multiple guests accessing the same files from the host filesystem.

    There are still some areas that need work, however. Metadata and the directory entry cache (dcache) cannot be shared, because data structures cannot be shared between the host and guests. There are two ways to handle that. Either there can be a round trip from the guest to the host for each operation to ensure the coherence of the metadata cache and dcache, or the guest can cache that information and somehow revalidate the cache on each operation without going to the host kernel.

  • Common needs for Samba and NFS

    Amir Goldstein led a discussion on things that the two major network filesystems for Linux, Samba and NFS, could cooperate on at the end of day one of the 2019 Linux Storage, Filesystem, and Memory-Management Summit. In particular, are there needs that both filesystems have that the kernel is not currently providing? He had some ideas of areas that might be tackled, but was looking for feedback from the assembled filesystem developers.

    He has recently just started looking at the kernel NFS daemon (knfsd) as it is a lesser use case for the customers of his company's NAS device. Most use Samba (i.e. SMB). He would like to see both interoperate better with other operating systems, though.

  • NFS topics

    Trond Myklebust and Bruce Fields led a session on some topics of interest in the NFS world at the 2019 Linux Storage, Filesystem, and Memory-Management Summit. Myklebust discussed the intersection of NFS and containers, as well adding TLS support to NFS. Fields also had some container changes to discuss, along with a grab bag of other areas that need attention.

    Myklebust began with TLS support for the RPC layer that underlies NFS. One of the main issues is how to do the upcall from the RPC layer to a user-space daemon that would handle the TLS handshake. There is kernel support for doing TLS once the handshake is complete; hardware acceleration of TLS was added in the last year based on code from Intel and Mellanox, he said. RPC will use that code, but there is still the question of handling the handshake.

More in Tux Machines

today's leftovers

  • Linux Weekly Roundup #35

    Hello and welcome to this week's Linux Roundup and what a wonderful week we had! We have plenty of Linux Distro releases and LibreOffice 6.3 RC1. The Linux distros with releases this week are Q4OS 3.8, SparkyLinux 5.8, Mageia 7.1, ArcoLinux 19.07.11, Deepin 15.11, ArchBang 2107-beta, Bluestar 5.2.1, Slackel 7.2 "Openbox" and Endeavour OS 2019.07.15. I looked at most of these Linux Distros, links below, I will look at some of them in the new week and some I will unfortunately not have a look at, for download links and more, please visit distrowatch.com Well, this is this week's Linux Roundup, thank you so much for your time! Have a great week!

  • Full Circle Magazine: Full Circle Weekly News #140
  • Christopher Allan Webber: ActivityPub Conf 2019

    That's right! We're hosting the first ever ActivityPub Conf. It's immediately following Rebooting Web of Trust in Prague. There's no admission fee to attend. (Relatedly, the conference is kind of being done on the cheap, because it is being funded by organizers who are themselves barely funded.) The venue, however, is quite cool: it's at the DOX Centre for Contemporary Art, which is itself exploring the ways the digital world is affecting our lives. If you plan on attending (and maybe also speaking), you should get in your application soon (see the flier for details). We've never done one of these, and we have no idea what the response will be like, so this is going to be a smaller gathering (about 40 people). In some ways, it will be somewhere between a conference and a gathering of people-who-are-interested-in-activitypub. As said in the flier, by attending, you are agreeing to the code of conduct, so be sure to read that.

Sysadmin Appreciation Day, IBM and Fedora

  • Gift ideas for Sysadmin Appreciation Day

    Sysadmin Appreciation Day is coming up this Friday, July 26. To help honor sysadmins everywhere, we want you to share your best gift ideas. What would be the best way a team member or customer could show their appreciation for you? As a sysadmin, what was the best gift you've ever received? We asked our writers the same question, and here are their answers: "Whilst working in the Ubuntu community on Edubuntu, I took it upon myself to develop the startup/shutdown sound scheme, which became the default in Ubuntu for, from what I can understand, the next decade. Whilst people had a love-hate relationship with my sound scheme, and rightly so, I had a love-hate relationship with my sound card during the development. At the time I had recorded all my sound samples using one sample rate, but my new sound card, as my motherboard had exploded a few days earlier, did not support it. I had two choices, resample all my samples (which I didn't really want to do) or buy a new sound card.

  • Red Hat OpenStack Platform with Red Hat Ceph Storage: Radosbench baseline performance evaluation

    Red Hat Ceph Storage is popular storage for Red Hat OpenStack Platform. Customers around the world run their hyperscale, production workloads on Red Hat Ceph Storage and Red Hat OpenStack Platform. This is driven by the high level of integration between Ceph storage and OpenStack private cloud platforms. With each release of both platforms, the level of integration has grown and performance and automation has increased. As the customer's storage and compute needs for footprints have grown, we have seen more interest towards running compute and storage as one unit and providing a hyperconverged infrastructure (HCI) layer based on OpenStack and Ceph. [...] Continuing the benchmarking series, in the next post you’ll learn performance insights of running multi-instance MySQL database on Red Hat OpenStack Platform and Red Hat Ceph Storage across decoupled and hyperconverged architectures. We’ll also compare results from a near-equal environment backed by all-flash cluster nodes.

  • The State of Java in Flathub

    For maintainers of Java-based applications in Flathub, it's worth noting that even if you consume the Latest OpenJDK extension in your application, users will not be broken by major updates because OpenJDK is bundled into your Flatpak. The implication of this for users is that they won't see updates to their Java version until the application maintainer rebuilds the application in Flathub. If you maintain a Java-based Flatpak application on Flathub, you can consume the latest version of your chosen OpenJDK stream (either LTS or Latest) simply by rebuilding; the latest version of that OpenJDK steam will be pulled in automatically.

  • Fedora Magazine: Contribute at the Fedora Test Week for kernel 5.2

    The kernel team is working on final integration for kernel 5.1. This version was just recently released, and will arrive soon in Fedora. This version has many security fixes included. As a result, the Fedora kernel and QA teams have organized a test week from Monday, Jul 22, 2019 through Monday, Jul 29, 2019. Refer to the wiki page for links to the test images you’ll need to participate. Read below for details.

Debian and Ubuntu Leftovers

  • Bootstrappable Debian BoF

    Greetings from DebConf 19 in Curitiba! Just a quick reminder that I will run a Bootstrappable Debian BoF on Tuesday 23rd, at 13.30 Brasilia time (which is 16.30 UTC, if I am not mistaken). If you are curious about bootstrappability in Debian, why do we want it and where we are right now, you are welcome to come in person if you are at DebCon or to follow the streaming.

  • Candy Tsai: Outreachy Week 6 – Week 7: Getting Code Merge

    You can’t overhear what others are doing or learn something about your colleagues through gossip over lunch break when working remotely. So after being stuck for quite a bit, terceiro suggested that we try pair programming. After our first remote pair programming session, I think there should be no difference in pair programming in person. We shared the same terminal, looked at the same code and discussed just like people standing side by side. Through our pair programming session, I found out that I had a bad habit. I didn’t run tests on my code that often, so when I had failing tests that didn’t fail before, I spent more time debugging than I should have. Pair programming gave insight to how others work and I think little improvements go a long way.

  • about your wiki page on I/O schedulers and BFQ
    Hi,
    this is basically to report outdated statements in your wiki page on
    I/O schedulers [1].
    
    The main problematic statement is that BFQ "...  is not ideal for
    devices with slow CPUs or high throughput I/O devices" because too
    heavy.  BFQ is definitely more sophisticated than any of the other I/O
    schedulers.  We have designed it that way to provide an incomparably
    better service quality, at a very low overhead.  As reported in [2],
    the execution time of BFQ on an old laptop CPU is 0.6 us per I/O
    event, against 0.2 us for mq-deadline (which is the lightest Linux I/O
    scheduler).
    
    To put these figures into context, BFQ proved to be so good for
    "devices with slow CPUs" that, e.g., Chromium OS migrated to BFQ a few
    months ago.  In particular, Google crew got convinced by a demo [3] I
    made for them, on one of the cheapest and slowest Chromebook on the
    market.  In the demo, a fast download is performed.  Without BFQ, the
    download makes the device completely unresponsive.  With BFQ, the
    device remains as responsive as if it was totally idle.
    
    As for the other part of the statement, "...  not ideal for ...  high
    throughput I/O devices", a few days ago I ran benchmarks (on Ubuntu)
    also with one of the fastest consumer-grade NVMe SSDs: a Samsung SSD
    970 PRO.  Results [4] can be summarized as follows.  Throughput with
    BFQ is about the same as with the other I/O schedulers (it couldn't be
    higher, because this kind of drives just wants the scheduler to stay
    as aside as possible, when it comes to throughput).  But, in the
    presence of writes as background workload, start-up times with BFQ are
    at least 16 times as low as with the other I/O schedulers.  In
    absolute terms, gnome-terminal starts in ~1.8 seconds with BFQ, while
    it takes at least 28.7 (!) seconds with the other I/O schedulers.
    Finally, only with BFQ, no frame gets lost in video-playing
    benchmarks.
    
    BFQ then provides other important benefits, such as from 5x to 10X
    throughput boost in multi-client server workloads [5].
    
    So, is there any chance that the outdated/wrong information on your
    wiki page [1] gets updated somehow?  If I may, I'd be glad to update
    it myself, after providing you with all the results you may ask.
    
    In addition, why doesn't Ubuntu too consider switching to BFQ as
    default I/O scheduler, for all drives that BFQ supports (namely all
    drives with a maximum speed not above ~500 KIOPS)?
    
    Looking forward to your feedback,
    Paolo
    
    
  • Should Ubuntu Use The BFQ I/O Scheduler?

    The BFQ I/O scheduler is working out fairly well these days as shown in our benchmarks. The Budget Fair Queueing scheduler supports both throughput and low-latency modes while working particularly well for consumer-grade hardware. Should the Ubuntu desktop be using BFQ by default? [...] But in addition to wanting to correct that Wiki information, Paolo pops the question of why doesn't Ubuntu switch to BFQ as the default I/O scheduler for supported drives. Though as of yet, no Ubuntu kernel developers have yet commented on the prospect of switching to BFQ.

Devices With Linux Support

  • Quest Releases KACE SDA & SMA Updates

    The update to 7.0 for KACE Systems Deployment Appliance is primarily about bringing a scope of endpoint management capabilities with new support for Linux devices to the table.

  • Rugged, Kaby Lake transport computer has a 10-port LAN switch with PoE

    Axiomtek’s Linux-ready “tBOX400-510-FL” transportation system has a 7th Gen Intel CPU and a 10-port managed switch with 8x M12-style 10/100Mbps PoE and 2x GbE ports. The rugged system also has 3x mini-PCIe slots and dual swappable SATA drives. Axiomtek has launched a fanless, Kaby Lake-U based transportation computer with a choice of power supplies designed for in-vehicle, marine, or railway applications. The rugged tBOX400-510-FL features a Qualcomm-driven, Layer 2 managed PoE switch with support for IP surveillance and video management applications. “Customers can connect IP cameras directly without installing an extra PoE switch, minimizing overall deployment costs and installation space onboard,” stated Axiomtek product manager Sharon Huang.