This patch adds the description to explain the accumulated power algorithm. Signed-off-by: Huang Rui <ray.huang@xxxxxxx> --- Documentation/hwmon/fam15h_power | 45 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) diff --git a/Documentation/hwmon/fam15h_power b/Documentation/hwmon/fam15h_power index 42bf04e..dc2bc69 100644 --- a/Documentation/hwmon/fam15h_power +++ b/Documentation/hwmon/fam15h_power @@ -45,3 +45,48 @@ This driver provides ProcessorPwrWatts and 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: +* power1_acc (PwrCPUave) -- 1.9.1 _______________________________________________ lm-sensors mailing list lm-sensors@xxxxxxxxxxxxxx http://lists.lm-sensors.org/mailman/listinfo/lm-sensors
