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diff --git a/Documentation/hwmon/fam15h_power b/Documentation/hwmon/fam15h_power new file mode 100644 index 000000000..fb594c281 --- /dev/null +++ b/Documentation/hwmon/fam15h_power @@ -0,0 +1,102 @@ +Kernel driver fam15h_power +========================== + +Supported chips: +* AMD Family 15h Processors +* AMD Family 16h Processors + + Prefix: 'fam15h_power' + Addresses scanned: PCI space + Datasheets: + BIOS and Kernel Developer's Guide (BKDG) For AMD Family 15h Processors + BIOS and Kernel Developer's Guide (BKDG) For AMD Family 16h Processors + AMD64 Architecture Programmer's Manual Volume 2: System Programming + +Author: Andreas Herrmann <herrmann.der.user@googlemail.com> + +Description +----------- + +1) Processor TDP (Thermal design power) + +Given a fixed frequency and voltage, the power consumption of a +processor varies based on the workload being executed. Derated power +is the power consumed when running a specific application. Thermal +design power (TDP) is an example of derated power. + +This driver permits reading of registers providing power information +of AMD Family 15h and 16h processors via TDP algorithm. + +For AMD Family 15h and 16h processors the following power values can +be calculated using different processor northbridge function +registers: + +* BasePwrWatts: Specifies in watts the maximum amount of power + consumed by the processor for NB and logic external to the core. +* ProcessorPwrWatts: Specifies in watts the maximum amount of power + the processor can support. +* CurrPwrWatts: Specifies in watts the current amount of power being + consumed by the processor. + +This driver provides ProcessorPwrWatts and CurrPwrWatts: +* power1_crit (ProcessorPwrWatts) +* power1_input (CurrPwrWatts) + +On multi-node processors the calculated value is for the entire +package and not for a single node. Thus the driver creates sysfs +attributes only for internal node0 of a multi-node processor. + +2) Accumulated Power Mechanism + +This driver also introduces an algorithm that should be used to +calculate the average power consumed by a processor during a +measurement interval Tm. The feature of accumulated power mechanism is +indicated by CPUID Fn8000_0007_EDX[12]. + +* Tsample: compute unit power accumulator sample period +* Tref: the PTSC counter period +* PTSC: performance timestamp counter +* N: the ratio of compute unit power accumulator sample period to the + PTSC period +* Jmax: max compute unit accumulated power which is indicated by + MaxCpuSwPwrAcc MSR C001007b +* Jx/Jy: compute unit accumulated power which is indicated by + CpuSwPwrAcc MSR C001007a +* Tx/Ty: the value of performance timestamp counter which is indicated + by CU_PTSC MSR C0010280 +* PwrCPUave: CPU average power + +i. Determine the ratio of Tsample to Tref by executing CPUID Fn8000_0007. + N = value of CPUID Fn8000_0007_ECX[CpuPwrSampleTimeRatio[15:0]]. + +ii. Read the full range of the cumulative energy value from the new +MSR MaxCpuSwPwrAcc. + Jmax = value returned. +iii. At time x, SW reads CpuSwPwrAcc MSR and samples the PTSC. + Jx = value read from CpuSwPwrAcc and Tx = value read from +PTSC. + +iv. At time y, SW reads CpuSwPwrAcc MSR and samples the PTSC. + Jy = value read from CpuSwPwrAcc and Ty = value read from +PTSC. + +v. Calculate the average power consumption for a compute unit over +time period (y-x). Unit of result is uWatt. + if (Jy < Jx) // Rollover has occurred + Jdelta = (Jy + Jmax) - Jx + else + Jdelta = Jy - Jx + PwrCPUave = N * Jdelta * 1000 / (Ty - Tx) + +This driver provides PwrCPUave and interval(default is 10 millisecond +and maximum is 1 second): +* power1_average (PwrCPUave) +* power1_average_interval (Interval) + +The power1_average_interval can be updated at /etc/sensors3.conf file +as below: + +chip "fam15h_power-*" + set power1_average_interval 0.01 + +Then save it with "sensors -s". |