Re: [PATCH v10 0/4] Support SMT control on arm64

[Shrikanth Hegde]

On 12/20/24 13:23, Yicong Yang wrote:
> From: Yicong Yang <yangyicong@xxxxxxxxxxxxx>
>
> The core CPU control framework supports runtime SMT control which
> is not yet supported on arm64. Besides the general vulnerabilities
> concerns we want this runtime control on our arm64 server for:
>
> - better single CPU performance in some cases
> - saving overall power consumption

EAS is disabled when SMT is present.
I am curious to know how power saving happens here.

> This patchset implements it in the following aspects:
>
> - Provides a default topology_is_primary_thread()
> - support retrieve SMT thread number on OF based system
> - support retrieve SMT thread number on ACPI based system
> - select HOTPLUG_SMT for arm64
>
> Tests has been done on our ACPI based arm64 server and on ACPI/OF\
> based QEMU VMs.