On Wed, Jan 18, 2017 at 10:29:15AM -0800, Srinivas Pandruvada wrote: > 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: Srinivas Pandruvada <srinivas.pandruvada@xxxxxxxxxxxxxxx> Queued to testing, thanks Srinivas. -- Darren Hart Intel Open Source Technology Center
