Tag Archives: Kernel

Linux 5.2/5.3 Kernel Performance On The AMD Ryzen 9 3900X


AMD --

With yesterday’s Windows 10 vs. Ubuntu 18.04 LTS Linux benchmarks for the AMD Ryzen 9 3900X, some suggested that the Linux performance could have been better if using a Linux 5.x kernel. Well, here are some benchmarks comparing the performance of Ubuntu 18.04.2 LTS with its Linux 4.18 kernel compared to Linux 5.2 stable as well as the brand new Linux 5.3 development kernel.

On the same Ryzen 9 3900X system, these three kernel releases (Ubuntu 18.04’s stock 4.18 kernel, Linux 5.2 stable, Linux 5.3 Git) were compared across a variety of workloads.

Sans graphics and I/O for any areas explicitly improved upon in recent kernel releases, the CPU performance itself went pretty much unchanged.

Obviously if you are using the open-source Intel/Radeon graphics in particular, I certainly recommend the newest kernel as possible for the updated drivers, but in terms of Zen 2 desktop CPU performance it was largely the same using the stock Ubuntu 18.04 LTS kernel.

Those wanting to look through the dozens of benchmarks individually, they are available via 1907278-HV-3900XLINU13 on OpenBenchmarking.org.

Looking ahead to Linux 5.4 late in 2019, that’s where there is the possibility of Zen 2 performance changes due to AMD’s new CPPC CPUFreq driver as one performance-sensitive change pending, but we’ll see what else comes about and other optimizations now that more Linux developers are getting their hands on these impressive processors.


XFS Gets Cleaned Up In Linux 5.3 Kernel Development Activity


LINUX STORAGE --

While not too eventful on the end-user feature front, the XFS file-system has seen another round of clean-ups with the ongoing Linux 5.3 merge window.

XFS maintainer Darrick Wong characterized the feature work for XFS in Linux 5.3 as “significant amounts of consolidations and cleanups in the log code; restructuring of the log to issue struct bios directly; new bulkstat ioctls to return v5 fs inode information (and fix all the padding problems of the old ioctl); the beginnings of multithreaded inode walks (e.g. quotacheck); and a reduction in memory usage in the online scrub code leading to reduced runtimes.

It’s not immediately exciting for end-users but hopefully will cleanup some open issues and the start of multi-threaded inode walks could help with performance along with the memory reduction work.

The complete list of Linux 5.3 XFS work can be found via this pull request.


The Linux Kernel Getting Fixed Up For Booting On Some Intel Systems – No “8254”


HARDWARE --

There have been Linux reports of problems pertaining to “8254 Clock Gating” going back a while but more so recently. This problem is some newer Intel Skylake~Apollolake derived systems particularly with Intel SoCs where certain systems ship with the 8254 PIT to be gated via a special register and up until now that has caused Linux to fail to boot.

With the PIT gating by default, Linux would fail to boot with a kernel panic over “IO-APIC + timer doesn’t work!” But as this panic would happen before the frame-buffer is even setup, it would be hard for users to diagnose and workaround. There has been a workaround often of toggling the “8254 Clock Gating” option within the affected systems’ BIOS. But now there’s a kernel patch pending to make Linux happy in the no-8254 configuration.

The patch contains additional details for those interested. That fix is currently queuing in the x86/apic tree. Given an uptick in recent reports around “8254 clock gating” woes appearing in Google search results, good to see Linux getting fixed for these Intel systems.


Oracle Releases Linux 4.14 Based “Unbreakable Enterprise Kernel R5 U2”


ORACLE --

Oracle today announced the general availability release of their Unbreakable Enterprise Kernel Release 5 Update 2 that pairs with their RHEL-derived Oracle Linux for offering a Linux 4.14 based kernel with various features on top.

The Unbreakable Enterprise Kernel Release 5 Update 2 is based on the upstream Linux 4.14.35 kernel while adding in Pressure Stall Information patches, the KTask framework for helping with parallelizing CPU-intensive kernel work, DTrace support for libpcap packet capture, a variety of file-system driver fixes, various virtualization updates back-ported from Linux 4.19, various hardware driver updates, Arm platform tuning, and NVMe driver updates back-ported from earlier versions of the Linux kernel.

Those wanting to learn more about today’s Oracle Unbreakable Enterprise Kernel Release 5 Update 2 can learn more at the Oracle Linux blog.


Ubuntu Expands Its Kernel Uploader Team


UBUNTU --

As a sign of the times with the Linux kernel being affected by an increasing number of CVEs (and particularly high profile ones at that), there are now more Ubuntu developers with upload rights for sending down new kernel upgrades.

Ubuntu’s Kernel Uploaders Team approved adding Tyler Hicks (a longtime Canonical developer working as an Ubuntu kernel engineer) to the kernel uploaders group as well as Juerg Haefliger (having worked on stable kernels and recent high profile CVE issues already) and Khalid Elmously (another Canonical employee and existing kernel team member).

The Ubuntu Kernel Uploaders is a small set of Ubuntu developers able to upload kernel packages directly into the package archive.

The greeting of these new kernel uploaders can be found on the ubuntu-devel mailing list.