Kernel 6.8 RC (Release Candidate) series

[Doug S]

Kernel 6.8-rc1 is available.

Just starting our usual per kernel RC series thread here. All I have done so far is compile and boot:

doug@s19:~$ uname -a
Linux s19 6.8.0-rc1-stock #1199 SMP PREEMPT_DYNAMIC Mon Jan 22 08:07:29 PST 2024 x86_64 x86_64 x86_64 GNU/Linux

[fyfe54]

Installed. So far, so good.

[1fallen]

To be expected breaks nVidia and zfs FYI.

I as well have not been running it long enough to point good or bad.

uname -r
6.8.0-060800rc1-generic

[corradoventu]

After installing kernel 6.8.0-060800rc1-generic on my Ubuntu Noble from https://kernel.ubuntu.com/mainline/ firefox and snap-store do not start
https://discourse.ubuntu.com/t/intro...elease/41958/2

[Bashing-om]

Introducing Kernel 6.8 for the 24.04 Noble Numbat Release

https://discourse.ubuntu.com/t/intro...release/41958/

"An experimental build of the latest Ubuntu Noble kernel based on the latest 6.8-rc* is available in ppa:canonical-kernel-team/unstable (Unstable Kernel Builds : “Canonical Kernel Team” team 6), this kernel will be updated weekly, until it will replace the main kernel in 24.04."

How about them apples Who'da thunk it

[Doug S]

Introducing Kernel 6.8 for the 24.04 Noble Numbat Release

https://discourse.ubuntu.com/t/intro...release/41958/

"An experimental build of the latest Ubuntu Noble kernel based on the latest 6.8-rc* is available in ppa:canonical-kernel-team/unstable (Unstable Kernel Builds : “Canonical Kernel Team” team 6), this kernel will be updated weekly, until it will replace the main kernel in 24.04."

How about them apples Who'da thunk it

I am particularly interested in, and have chimed in on:

Additional non-upstream features that we may consider for inclusion (WIP):

Enable low-latency features by default (Bug #2023007 “kernel .config lowlatency improvements” : Bugs : linux-lowlatency package : Ubuntu)

EDIT: Sorry, it is this related bug that I chimed in on and would like to be included in 24.04.

[Doug S]

While kernel 6.8-rc2 is available at kernel.org, the Ubuntu mainline AMD64 compile failed with the good old:

make[4]: /bin/sh: Resource temporarily unavailable

EDIT: My first time booting -rc2 the system ended up in recovery mode. Another re-boot and it was fine. Operator error or something else, I don't know.

doug@s19:~$ uname -a
Linux s19 6.8.0-rc2-stock #1204 SMP PREEMPT_DYNAMIC Sun Jan 28 20:11:00 PST 2024 x86_64 x86_64 x86_64 GNU/Linux

[corradoventu]

6.8.0-060800rc3 from https://kernel.ubuntu.com/mainline/ works fine

corrado@corrado-n9-nn-1210:~$ inxi -SMxc
System:
  Host: corrado-n9-nn-1210 Kernel: 6.8.0-060800rc3-generic arch: x86_64
    bits: 64 compiler: gcc v: 13.2.0
  Desktop: GNOME v: 45.3 Distro: Ubuntu 24.04 (Noble Numbat)
Machine:
  Type: Desktop System: Gigabyte product: H510M H v: -CF
    serial: <superuser required>
  Mobo: Gigabyte model: H510M H v: x.x serial: <superuser required>
    UEFI: American Megatrends LLC. v: F14 date: 03/25/2022
corrado@corrado-n9-nn-1210:~$

[Doug S]

For these conditions:
CPU frequency scaling driver: intel_cpufreq (a.k.a intel_pstate in passive mode)
CPU frequency scaling governor: schedutil
HWP (HardWare Pstate) control (a.k.a. Intel_speedshift): Enabled

Reduced maximum CPU frequencies are not been enforced. Kernel 6.7 was fine. Kernel 6.8-rc1 is not.
I am about 2/3rds of the way through bisecting the kernel in an attempt to isolate the bad commit.

I have not tried other configurations.

Processor: Intel(R) Core(TM) i5-10600K CPU @ 4.10GHz

EDIT:

# first bad commit: [9c0b4bb7f6303c9c4e2e34984c46f5a86478f84d] sched/cpufreq: Rework schedutil governor performance estimation

[corradoventu]

I had problems with Kernel 6.8-rc1, Kernel 6.8-rc3 is ok for me.