• Srinivas Pandruvada's avatar
    platform/x86: Support Turbo Boost Max 3.0 for non HWP systems · 4ec567b8
    Srinivas Pandruvada authored
    On platforms supporting Intel Turbo Boost Max Technology 3.0, the
    maximum turbo frequencies (turbo ratio) of some cores in a CPU package
    may be higher than the other cores in the same package.  In that case,
    better performance can be achieved by making the scheduler prefer to run
    tasks on the CPUs with higher max turbo frequencies.
    
    On Intel® Broadwell Xeon systems, it is optional to turn on HWP
    (Hardware P-States). When HWP is not turned on, the BIOS doesn't
    present required CPPC (Collaborative Processor Performance Control)
    tables. This table is used to get the per CPU core maximum performance
    ratio and inform scheduler (in cpufreq/intel_pstate driver).
    
    On such systems the maximum performance ratio can be read via over
    clocking (OC) mailbox interface for each CPU. This interface is not
    architectural and can change for every model of processors.
    
    This driver reads maximum performance ratio of each CPU and set up
    the scheduler priority metrics. In this way scheduler can prefer CPU
    with higher performance to schedule tasks.
    Signed-off-by: default avatarSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
    Signed-off-by: default avatarDarren Hart <dvhart@linux.intel.com>
    4ec567b8
intel_turbo_max_3.c 4.02 KB