The Changes & New Features For Linux 4.18, Benchmarks Are Incoming
With the early release of Linux 4.18-rc1, feature development on Linux 4.18 is over and it's onto roughly eight weeks worth of testing and bug fixes. For those that are behind in their Phoronix reading with our extensive and original reporting on the Linux 4.18 merge window happenings, here is our recap of the big changes that made it into Linux 4.18. We are also in the process of firing off the start of our Linux 4.18 kernel benchmarks.
Highlights of the Linux 4.18 kernel come down to new AMDGPU support improvements, mainlining of the V3D DRM driver, initial open-source work on NVIDIA Volta GV100 hardware, merging of the Valve Steam Controller kernel driver, merging of the BPFILTER framework, ARM Spectre mitigation work, Speck file-system encryption support, removal of the Lustre file-system, the exciting restartable sequences system call was merged, the new DM writecache target, and much more. While there are a lot of new features, Linux 4.18-rc1 is actually over 100k lines of code lighter than Linux 4.17.0 thanks to the removal of outdated/obsolete code.
Below are the highlights sorted by subsystem based upon my original reporting of kernel mailing list and Git monitoring over the past two weeks.
Graphics / Direct Rendering Manager:
- The AMDGPU DRM kernel driver has initial support for the yet-to-launch Vega 20 graphics processor.
- There is also initial support for Vega M graphics that is the Polaris/Vega graphics hardware found within the new Intel "Kabylake G" processors for providing faster onboard graphics than Intel's own UHD/HD Graphics.
- AMDGPU also now has Vega power profile support, clock voltage control improvements, and other Vega improvements. Similarly, the AMDKFD compute driver now supports Vega/GFX9 so this mainline AMD compute kernel driver can work with ROCm/OpenCL in user-space for this latest-generation AMD graphics hardware.
- Early work on Intel Icelake "Gen 11" graphics support that will eventually succeed the still yet to be out Cannonlake hardware. Icelake is starting to get into shape and likely around Linux 5.0~5.1, it will presumably be in good shape if the timing holds true based upon past Intel graphics enablement efforts, which still should be plenty of time ahead of Icelake CPUs actually shipping.
- The V3D DRM driver previously known as Broadcom's VC5 DRM driver was merged. This is for the next-gen VideoCore V hardware and what hopefully will appear in new Raspberry Pi hardware in the not too distant future.
- Xen-front was merged as a new DRM driver for a Xen hypervisor para-virtualized display front-end.
- Initial NVIDIA GV100 Volta support within the Nouveau DRM driver though right now is basically good for just kernel mode-setting.
- Other work includes more Intel HDCP content protection work, DisplayPort MST fixes for Intel.
- Sample mediated device display drivers for VFIO.
- ARM64/AArch64/ARMv8 mitigation for Spectre V4 with Speculative Store Bypass Disable.
- Meanwhile for older ARM 32-bit hardware there is now finally Spectre V1/V2 mitigation while the 64-bit ARM (and other architectures) have of course had this mitigation for months.
- Continued work on bringing up support for the Chinese x86 CPUs, a.k.a. the Zhaoxin / Centaur x86 CPUs on Linux based upon VIA IP.
- The older AMD Stoney Ridge and Bristol Ridge AMD APUs finally have temperature reporting support.
- HWP Iowait boosting for the P-State scaling driver for Intel Xeon Skylake servers/workstations to yield better I/O performance.
- New AMD patches around SSBD for speculative store bypass disable with Spectre V4 on AMD hardware when having new microcode/CPUs.
- Continued work on getting the RISC-V Linux code into shape and there's now initial integration with the perf subsystem.
- Support for the Qualcomm Snapdragon 845 SoC albeit it will continue to be improved more in forthcoming cycles.
Linux Storage / File-Systems:
- Speck file-system encryption support as the controversial Speck encryption support developed by the NSA but added anyways to help low-end Android devices with some level of data encryption.
- The Lustre file-system has been removed from the mainline kernel due to this code not being maintained well upstream. Lustre continues to be maintained out-of-tree.
- The DM writecache target (https://www.phoronix.com/news/Linux-4.18-DM-Writecache) was merged for helping with caching around databases.
- Merging of the independent Steam Controller HID driver for the Linux kernel.
- The Chromebook tablet switch driver was merged for helping out some x86 Google Chromebooks that are the 2-in-1 / convertible types for switching between modes.
- BPFILTER was merged as the BPF-based solution for eventually overhauling the Linux kernel's packet filtering and firewall code.
- Microsoft Hyper-V improvements for KVM.
- More improvements to the kernel's scheduler code for helping out schedutil, NUMA, virtual CPUs, and more.
- Continued Linux power management updates.
- Ongoing work for preparing for Year 2038 support.
- The new Restartable Sequences system call that can help with performance and more.
There continues to be bi-daily Linux kernel Git benchmarks at LinuxBenchmarking.com while beginning in the week ahead will be some more concentrated benchmarks looking at the various major alterations and new features that landed with Linux 4.18. If you enjoy all my open-source news and Linux benchmarking and hardware reviews that happen every single day of the year, you can show your support by joining Phoronix Premium.
If all goes well, Linux 4.18.0 should debut as stable around the middle of August.
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