diff options
author | Ionela Voinescu <ionela.voinescu@arm.com> | 2022-03-10 14:54:50 +0000 |
---|---|---|
committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2022-03-10 20:21:58 +0100 |
commit | 9924fbb51e0ae30b8d7eec7c1c839d74da9678b3 (patch) | |
tree | b9eba95a9ca8cc9f5b3735c479b217db0aa9c6bd /arch/arm64/include | |
parent | 1132e6de11cfc334b44f609792664f1bc3055c52 (diff) | |
download | linux-9924fbb51e0ae30b8d7eec7c1c839d74da9678b3.tar.bz2 |
arch_topology: obtain cpu capacity using information from CPPC
Define topology_init_cpu_capacity_cppc() to use highest performance
values from _CPC objects to obtain and set maximum capacity information
for each CPU. acpi_cppc_processor_probe() is a good point at which to
trigger the initialization of CPU (u-arch) capacity values, as at this
point the highest performance values can be obtained from each CPU's
_CPC objects. Architectures can therefore use this functionality
through arch_init_invariance_cppc().
The performance scale used by CPPC is a unified scale for all CPUs in
the system. Therefore, by obtaining the raw highest performance values
from the _CPC objects, and normalizing them on the [0, 1024] capacity
scale, used by the task scheduler, we obtain the CPU capacity of each
CPU.
While an ACPI Notify(0x85) could alert about a change in the highest
performance value, which should in turn retrigger the CPU capacity
computations, this notification is not currently handled by the ACPI
processor driver. When supported, a call to arch_init_invariance_cppc()
would perform the update.
Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Tested-by: Valentin Schneider <valentin.schneider@arm.com>
Tested-by: Yicong Yang <yangyicong@hisilicon.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'arch/arm64/include')
0 files changed, 0 insertions, 0 deletions