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

On 2025/2/28 19:12, Dietmar Eggemann wrote:

On 18/02/2025 15:10, Yicong Yang wrote:

quoted

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.

[...]

quoted

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:

will fix.

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

Thanks.