Power Management and Thermal Control Microconference Accepted into 2020 Linux Plumbers Conference

We are pleased to announce that the Power Management and Thermal Control Microconference has been accepted into the 2020 Linux Plumbers Conference!

Power management and thermal control is an important area in the Linux ecosystem to help with the global environment. Optimizing the amount of work that is achieved while having long battery life and keeping the box from overheating is critical in today’s world. This meeting will focus on continuing to have Linux be an efficient operating system while still lowering the cost of running a data center.

Last year’s meetup at Linux Plumbers resulted in the introduction of thermal pressure support into the CPU scheduler as well as several improvements to the thermal framework, such as a netlink implementation of thermal notification and improvements to CPU cooling. Discussions from last year also helped to improve systems-wide suspend testing tools.

This year’s topics to be discussed include:

Come and join us in the discussion about extending the battery life of your laptop and keeping it cool.

We hope to see you there!

VFIO/IOMMU/PCI Microconference Accepted into 2020 Linux Plumbers Conference

We are pleased to announce that the VFIO/IOMMU/PCI Microconference has been accepted into the 2020 Linux Plumbers Conference!

The PCI interconnect specification, the devices implementing it, and the system IOMMUs providing memory/access control to them are incorporating more and more features aimed at high performance systems (eg PCI ATS (Address Translation Service)/PRI(Page Request Interface), enabling Shared Virtual Addressing (SVA) between devices and CPUs), that require the kernel to coordinate the PCI devices, the IOMMUs they are connected to and the VFIO layer used to manage them (for userspace access and device passthrough) with related kernel interfaces that have to be designed in-sync for all three subsystems.

The kernel code that enables these new system features requires coordination between VFIO/IOMMU/PCI subsystems, so that kernel interfaces and userspace APIs can be designed in a clean way.

The following was a result of last years successful Linux Plumbers microconference:

  • Software defined Non-Transparent Bridges (NTB) can now be implemented using the PCIe endpoint subsystem NTB using PCIe endpoints can now be represented using configfs rather than using device tree.
  • User interfaces for per-group default IOMMU domain type patches have been merged.
  • IO Address Space Identifier (IOASID) allocator has been merged and later support was added for custom allocator for guest use.

Last year’s Plumbers resulted in a write-up justifying the dual-stageSMMUv3 integration but more work is needed to persuade the relevant maintainers.

Topics for this year include (but not limited to):


  • Shared Virtual Addressing (SVA) interface
  • Single-root I/O Virtualization(SRIOV)/ Process Address Space ID (PASID) integration
  • PASID in SRIOV virtual functions
  • Device assignment/sub-assignment

  • IOMMUs virtualization: Partially discussed at LPC19 but further discussion needed for virtio-iommu firmware bindings (ie ACPI) and vSMMUv3 development
  • IOMMU drivers SVA interface consolidation:
    • Possible IOMMU core changes (like splitting up iommu_ops, better integration with device-driver core)
    • DMA-API layer interactions and how to get towards generic dma-ops for IOMMU drivers
  • Sharing Extended Page Tables with VT-d 2nd level

Come and join us in the discussion in helping Linux keep up with the new features being added to the PCI interconnect specification.

We hope to see you there!

RISC-V Microconference Accepted into 2020 Linux Plumbers Conference

We are pleased to announce that the RISC-V Microconference has been accepted into the 2020 Linux Plumbers Conference!

The RISC-V ecosystem is gaining momentum at such an astounding speed that it wouldn’t be unfair to compare it to the early days of the Linux ecosystem’s growth. There are a plethora of Linux kernel features that have been added to RISC-V and many more are waiting to be reviewed in the mailing list. Some of them resulted from direct discussions during last year’s RISC-V microconference. For example, RISC-V has a standard boot process along with a well-defined supervisor binary specification (SBI) and cpu hotplug feature. KVM support is very close to being merged and just waiting for official ratification of the H extension. NoMMU support for Linux kernel has already been merged.

Here are a few of the expected topics and current problems in RISC-V Linux land that we would like to cover.

  • RISC-V Platform Specification Progress: Unix platform specification added the improved SBI v0.2 specification this year. We will discuss the next set of specifications that should be added to standardize the requirements for RISC-V Linux.
  • Making RISC-V Embedded Base Boot Requirement (EBBR) compatible: There are ongoing efforts to add UEFI support for RISC-V Linux kernel. As a result, RISC-V can be fully EBBR compatible. We will discuss the current progress and what’s the best approach to make that happen.
  • RISC-V 32-bit glibc port: This will include details about the 64-bit time_t problem and how RISC-V 32 is going to be the first 32-bit architecture with a 64-bit time_t. What still needs to be done for 32-bit support? How do we get this merged? We will also like to discuss the plan to test and maintain it once it is merged.
  • Developing and improving BPF JITs using formal verification.: This discussion will review our ongoing efforts of applying the Serval automated formal verification framework to BPF JITs in the Linux kernel. Serval has been used to find new bugs, verify new optimizations, and to develop a new BPF JIT for 32-bit RISC-V. We will discuss possible future roles of formal verification in the JIT development process, and how formal verification can enable future optimizations that would otherwise be difficult to test.
  • RISC-V hypervisor extension : The hypervisor extension v0.5 is already available in the latest Qemu and v0.6.1 patches are already in the mailing list. The kvm patchset has been on the mailing list and waiting to be merged. We will discuss the ongoing designs for nested hypervisor implementation.
  • An introduction of vector ISA support in RISCV Linux: We will discuss the implementation of vector support in Linux kernel, how user space can get its layout or size and the future work for Linux kernel and glibc.
  • RISC-V Linux Tracing Status: The single-step trap exception is an ancient technology that has been supported by many CPU architectures, but RISC-V ISA does not support this feature. By examining the pain points in RISC-V linux kprobe/uprobe development, we want to explore introducing a new single-step hardware mechanism to help the Linux tracing infrastructure.

Come join us and participate in the discussion on how we can improve the support for RISC-V in the Linux kernel.

We hope to see you there!

You, Me, and IoT Two Microconference Accepted into 2020 Linux Plumbers Conference

We are pleased to announce that the You, Me, and IoT Microconference has been accepted into the 2020 Linux Plumbers Conference!

As everyday devices start to become more connected to the internet, the infrastructure around it constantly needs to be developed. The Internet of Things (IoT) in the Linux ecosystem is looking brighter every day. The
development rate of the Zephyr RTOS in particular is accelerating dramatically and we are now up to 2 commits per hour[1]! LoRa WAN made it into Zephyr release 2.2 as well.

The principles for IoT are still the same: data-driven controls for remote endpoints such as

  • on-off switches
  • dimmable switches
  • temperature controls
  • door and window sensors
  • metering
  • cameras
  • generally, peripherals connected via remote embedded buses like GPIO, I2C, SPI

A large focus of industry heavyweights continues to be interoperability; we are seeing a growing trend in moving toward IP-centric network communications. Using IP natively ensures that it is extremely easy for end-nodes and edge devices to communicate to The Cloud but it also means that IoT device security is more important than ever.

Last year’s successful microconference has brought about several changes in the IoT space. The Linux + Zephyr + Greybus solution now works over nearly all physical layers (#exactsteps for IEEE 802.15.4 and BLE). BeagleBoard.org is also now preparing a next-gen hardware revision of the BeagleConnect to provide both a hobbyist and professional-friendly IoT platform. BlueZ has begun making quarterly releases, much to the delight of last year’s attendees, and members of the linux-wpan / netdev community have implemented RPL, an IPv6 routing protocol for lossy networks.

This year’s topics to be discussed include:

  • Working to make wireless firmware images for popular embedded Linux distros more stable
  • Mitigating TCP issues in bandwidth-limited wireless networks
  • Providing ways for users to interact with the IEEE 802.15.4 MAC layer
  • Coming up with a common set of tools for the Enterprise Linux Distribution

Come and join us in some heated but productive discussions in making your everyday devices communicate with the world around them.

[1]For reference, Linux receives approximately 9 commits per hour

We hope to see you there!


LLVM Microconference Accepted into 2020 Linux Plumbers Conference

We are pleased to announce that the LLVM Microconference has been accepted into the 2020 Linux Plumbers Conference!

The LLVM toolchain has made significant progress over the years and many kernel developers are now using it to build their kernels. It is still the one toolchain that can natively compile C into BPF byte code. Clang (the C frontend to LLVM) is used to build Android and ChromeOS kernels and others are in the process of testing to use Clang to build their kernels.

Many topics still need to be resolved, and are planned to be discussed here.
These include (but not limited to):

  • Barriers to in-tree Rust support?
  • Memory ordering and compiler verification
  • Kernel LTO with clang and optimizing using profiling information (PGO and AutoFDO)
  • Clang related Continuous Integration topics:
  • Improving KernelCI clang integration
  • Improving 0day bot clang integration
  • Using clang with tuxbuild
  • Setting up CI on the LLVM side for Linux kernel builds
  • Cross LLVM/binutils testing
  • Measuring and improving kernel compile times with Clang
  • Builds of LLVM for kernel.org
  • Using clang-tidy and clang-format with kernel code
  • Coordination between clang and GCC developers on GNU C extensions used in the kernel code
  • asm goto w/ outputs (CONFIG_CC_HAS_ASM_GOTO_OUTPUT)
  • Parsing issues with genksyms
  • clang feedback session; what’s working, what can be improved.

Come and join us in the discussion of improving this new toolchain to make it the most useable
for everyone!

We hope to see you there!

Open Printing Microconference Accepted into 2020 Linux Plumbers Conference

We are pleased to announce that the Open Printing Microconference has been accepted into the 2020 Linux Plumbers Conference!

Building on the work already done in driverless printing since last year’s microconference session; driverless scanning has emerged as an active new topic since last year’s Plumbers. We’re seeing many new printer application projects emerge that will benefit 3D printing as well. With Driverless scanning and printing making good progress and improvements, now is the time to talk about driverless/IPP fax as well.

Topics to discuss include

Come join us and participate in the discussion to bring Linux printing,
scanning and fax a better experience.

If you already want to start the discussion right now or tell us
something before the conference starts, do it in the comments sections
of the linked pages.

We hope to see you there!

Reminder for LPC 2020 Town Hall: The Kernel Report

Thursday is approaching!

On July 16th at 8am PST / 11am EST / 3pm GMT the Kernel Report talk by Jon Corbet of LWN will take place on the LPC Big Blue Button platform! It will also be available on a YouTube Live stream.

Please join us at this URL: https://linuxplumbers.lwn.net/b/LPC-kernel-report.

The Linux kernel is at the core of any Linux system; the performance and capabilities of the kernel will, in the end, place an upper bound on what the system as a whole can do. This talk will review recent events in the kernel development community, discuss the current state of the kernel and the challenges it faces, and look forward to how the kernel may address those challenges. Attendees of any technical ability should gain a better understanding of how the kernel got to its current state and what can be expected in the near future.

The Plumbers Code of Conduct will be in effect for this event. The event will be recorded.

linux/arch/* Microconference Accepted into 2020 Linux Plumbers Conference

We are pleased to announce that the linux/arch/* Microconference has
been accepted into the 2020 Linux Plumbers Conference!

Linux supports over twenty architectures.

Each architecture has its own sub-directory within the Linux-kernel arch/ directory containing code specific for that architecture. But that code is not always unique to the architecture.

In many cases, code in one architecture was copy-pasted from another, leaving for a lot of unnecessary code duplication. This makes it harder to fix, update and maintain functionality relying on the architecture specific code.

There’s room to improve, consolidate and generalize the code in these
directories, and that is the goal of this microconference.

Topics to discuss include:

  • Reducing code duplication and generalizing the common code in arch/
  • Moving syscall processing to C
  • Memory models (FLAT, DISCONTIGOUS and SPARSE)
  • Devicetree
  • Future of highmem
  • Identifying old machine support:
    1. Still in active use
    2. Only in hobbyist/retro-computing
    3. Completely obsolete and broken

Come join us and participate in the discussion to bring Linux architectures closer together.

We hope to see you there!

Android Microconference Accepted into 2020 Linux Plumbers Conference

We are pleased to announce that the Android Microconference has been accepted into the 2020 Linux Plumbers Conference!

A few years ago the Android team announced their desire to try to set a path for creating a Generic Kernel Image (GKI) which would enable the decoupling of Android kernel releases from hardware enablement. Since then, much work has been done by many parties to make this vision a reality. Last year’s Linux Plumber’s Android microconference brought about work on monitoring and stabilizing the Android in-kernel ABI, solutions to issues associated with modules and supplier-consumer dependencies have landed in the upstream Linux kernel, and vendors have started migrating from using the ION driver to the DMA-BUF heaps that are now supported in upstream Linux. For a report on progress made since last year MC see here.

This year several devices now work with GKI making their kernel upgradable without requiring porting efforts, but this work exposed several additional issues. Thus the topics for this year’s Android microconference include:

  • GKI compatibility in Android R, how did it go?
  • Ecosystem:
    1. Experience with GKI
    2. What’s the next phase — GKI 2.0 in Android S (what is yet to be figured out)
  • Update on Kernel Module Interface (KMI) enforcement tools
  • Upstreaming debt from GKI work
  • DMA-BUF Heaps (vs the ION driver) and DMA API model limitations discussion
  • Patches in common needed to boot the Android Open Source Project (AOSP) with mainline
  • Bootloader standardization
  • Upstream plan for FS updates (sdcardfs, fuse, others) and Virtual A/B partitions
  • SEpolicy integration strategies and tools
  • Protected KVM use in Android
  • Open source package integration in the AOSP

Come and join us in help making the upstream Linux kernel work out of the box on your Android device!

We hope to see you there!

GNU Tools Track Added to Linux Plumbers Conference 2020

We are pleased to announce that we have added an additional track to LPC 2020: the GNU Tools track. The track will run for the 5 days of the conference.
For more information please see the track wiki page.
The call for papers is now open and will close on July 31 2020. To submit a proposal please refer to the wiki page above.

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