Re: [PATCH v11 0/4] Support SMT control on arm64

Dietmar Eggemann
2025-02-28T11:59:52Z

On 18/02/2025 15:10, Yicong Yang wrote:
> From: Yicong Yang <yangyicong@hisilicon.com>
>
> 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
>
> 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.

[...]

> Yicong Yang (4):
> cpu/SMT: Provide a default topology_is_primary_thread()
> arch_topology: Support SMT control for OF based system
> arm64: topology: Support SMT control on ACPI based system
> arm64: Kconfig: Enable HOTPLUG_SMT
>
> arch/arm64/Kconfig | 1 +
> arch/arm64/kernel/topology.c | 66 +++++++++++++++++++++++++++++
> arch/powerpc/include/asm/topology.h | 1 +
> arch/x86/include/asm/topology.h | 2 +-
> drivers/base/arch_topology.c | 27 ++++++++++++
> include/linux/topology.h | 22 ++++++++++
> 6 files changed, 118 insertions(+), 1 deletion(-)

With the review comments on the individual patches [0-3]/4:

Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>