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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
commit | 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch) | |
tree | a94efe259b9009378be6d90eb30d2b019d95c194 /Documentation/hwmon/fam15h_power.rst | |
parent | Initial commit. (diff) | |
download | linux-upstream/5.10.209.tar.xz linux-upstream/5.10.209.zip |
Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | Documentation/hwmon/fam15h_power.rst | 131 |
1 files changed, 131 insertions, 0 deletions
diff --git a/Documentation/hwmon/fam15h_power.rst b/Documentation/hwmon/fam15h_power.rst new file mode 100644 index 000000000..fdde632c9 --- /dev/null +++ b/Documentation/hwmon/fam15h_power.rst @@ -0,0 +1,131 @@ +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". |