Re: [GIT pull] smp/core for v6.6-rc1

From: Michael Ellerman
Date: Tue Sep 05 2023 - 12:57:14 EST


Thomas Gleixner <tglx@xxxxxxxxxxxxx> writes:
> Linus,
>
> please pull the latest smp/core branch from:
>
> git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git smp-core-2023-08-28
>
> up to: e0a99a839f04: Documentation: core-api/cpuhotplug: Fix state names
>
>
> Updates for the CPU hotplug core:
>
> - Support partial SMT enablement.
>
> So far the sysfs SMT control only allows to toggle between SMT on and
> off. That's sufficient for x86 which usually has at max two threads
> except for the Xeon PHI platform which has four threads per core.
>
> Though PowerPC has up to 16 threads per core and so far it's only

The threads per core value comes from firmware, so in theory it can be
anything.

But in practice the max on any existing system is 8 threads per core.

cheers