Control: reassign -1 src:libvirt 8.9.0-1
On Thu, Nov 24, 2022 at 10:10:49AM +0100, Philipp Marek wrote:
> Package: src:linux
> Version: 6.0.8-1
> Severity: important
> X-Debbugs-Cc: phil...@marek.priv.at
>
>
> Sorry about the German messages.
>
> libvirt version: 8.9.0, package: 1 (Andrea Bolognani <e...@kiyuko.org>
> Sat, 19 Nov 2022 23:00:34 +0100)
>
> Nicht unterstützte Konfiguration: SCHED_CORE not supported by kernel
> Initialisierung des QEMU Status-Treibers fehlgeschlagen: Nicht
> unterstützte Konfiguration: SCHED_CORE not supported by kernel
> Treiber Status Initialisierung fehlgeschlagen
>
> My libvirt-daemon is 8.9.0-1; downgrading to 8.5.0-1 makes it work
> again, should the error be reported against that one,
> or does it make sense to recompile the kernel with that config?
Doing for now the reassignment to src:libvirt. In fact SCHED_CORE has
been disabled by default with upstream commit, d2343cb8d154
("sched/core: Disable CONFIG_SCHED_CORE by default"), in v5.14-rc1:
| commit d2343cb8d154fe20c4499711bb3a9af2095b2b4b
| Author: Ingo Molnar <mi...@kernel.org>
| Date: Mon Jun 28 21:55:16 2021 +0200
|
| sched/core: Disable CONFIG_SCHED_CORE by default
|
| This option at minimum adds extra code to the scheduler - even if
| it's default unused - and most users wouldn't want it.
|
| Reported-by: Linus Torvalds <torva...@linux-foundation.org>
| Signed-off-by: Ingo Molnar <mi...@kernel.org>
|
| diff --git a/kernel/Kconfig.preempt b/kernel/Kconfig.preempt
| index bd7c4147b9a8..5876e30c5740 100644
| --- a/kernel/Kconfig.preempt
| +++ b/kernel/Kconfig.preempt
| @@ -102,7 +102,6 @@ config PREEMPT_DYNAMIC
|
| config SCHED_CORE
| bool "Core Scheduling for SMT"
| - default y
| depends on SCHED_SMT
| help
| This option permits Core Scheduling, a means of coordinated task
| @@ -115,7 +114,8 @@ config SCHED_CORE
| - mitigation of some (not all) SMT side channels;
| - limiting SMT interference to improve determinism and/or
performance.
|
| - SCHED_CORE is default enabled when SCHED_SMT is enabled -- when
| - unused there should be no impact on performance.
| + SCHED_CORE is default disabled. When it is enabled and unused,
| + which is the likely usage by Linux distributions, there should
| + be no measurable impact on performance.
I have not checked what other distributions do, but given the above it
looks to me that we are doing already the okayish thing for
distributions. Libvirt-maintainers, what is your take on it?
How is your /etc/libvirt/qemu.conf configured with respect to the
"sched_core" setting?
Regards,
Salvatore
