The AMD Heterogeneous core design and Hardware Feedback Interface (HFI) provide behavioral classification and a dynamically updated ranking table for the scheduler to use when choosing cores for tasks. Threads are classified during runtime into enumerated classes. Currently, the driver supports 3 classes (0 through 2). These classes represent thread performance/power characteristics that may benefit from special scheduling behaviors. The real-time thread classification is consumed by the operating system and is used to inform the scheduler of where the thread should be placed for optimal performance or energy efficiency. The thread classification helps to select CPU from a ranking table that describes an efficiency and performance ranking for each classification from two dimensions. The ranking data provided by the ranking table are numbers ranging from 0 to 255, where a higher performance value indicates higher performance capability and a higher efficiency value indicates greater efficiency. All the CPU cores are ranked into different class IDs. Within each class ranking, the cores may have different ranking values. Therefore, picking from each classification ID allows the scheduler to select the best core while threads are classified into the specified workload class. The cores ranking table is provided with PCCT subspace type 4 shared memory, which includes the memory base address and length The series is based off linux-pm/bleeding-edge branch firstly, will be rebased to platform-drivers-x86 in v2. Thanks and BR, Perry. Perry Yuan (11): Documentation: x86: Add AMD Hardware Feedback Interface documentation MAINTAINERS: Add maintainer entry for AMD Hardware Feedback Driver x86/cpufeatures: add X86_FEATURE_WORKLOAD_CLASS feature bit x86/msr-index: define AMD heterogeneous CPU related MSR platform/x86: hfi: Introduce AMD Hardware Feedback Interface Driver platform/x86/: hfi: parse CPU core ranking data from shared memory platform/x86/: hfi: init per-cpu scores for each class platform/x86/: hfi: add online and offline callback support platform/x86/: hfi: add power management callback x86/process: Clear hardware feedback history for AMD processors x86/cpu: Enable SD_ASYM_PACKING for DIE Domain on AMD Processors Documentation/arch/x86/amd-hfi.rst | 116 +++++ Documentation/arch/x86/index.rst | 1 + MAINTAINERS | 9 + arch/x86/include/asm/cpufeatures.h | 1 + arch/x86/include/asm/hreset.h | 6 + arch/x86/include/asm/msr-index.h | 5 + arch/x86/kernel/cpu/common.c | 18 + arch/x86/kernel/cpu/scattered.c | 1 + arch/x86/kernel/process_32.c | 3 + arch/x86/kernel/process_64.c | 3 + arch/x86/kernel/smpboot.c | 3 +- drivers/platform/x86/amd/Kconfig | 1 + drivers/platform/x86/amd/Makefile | 1 + drivers/platform/x86/amd/hfi/Kconfig | 21 + drivers/platform/x86/amd/hfi/Makefile | 7 + drivers/platform/x86/amd/hfi/hfi.c | 665 ++++++++++++++++++++++++++ 16 files changed, 860 insertions(+), 1 deletion(-) create mode 100644 Documentation/arch/x86/amd-hfi.rst create mode 100644 arch/x86/include/asm/hreset.h create mode 100644 drivers/platform/x86/amd/hfi/Kconfig create mode 100644 drivers/platform/x86/amd/hfi/Makefile create mode 100644 drivers/platform/x86/amd/hfi/hfi.c -- 2.34.1
