On 27.05.2025 10:48, Penny Zheng wrote: > amd-cppc is the AMD CPU performance scaling driver that introduces a > new CPU frequency control mechanism on modern AMD APU and CPU series in > Xen. The new mechanism is based on Collaborative Processor Performance > Control (CPPC) which provides finer grain frequency management than > legacy ACPI hardware P-States. Current AMD CPU/APU platforms are using > the ACPI P-states driver to manage CPU frequency and clocks with > switching only in 3 P-states. CPPC replaces the ACPI P-states controls > and allows a flexible, low-latency interface for Xen to directly > communicate the performance hints to hardware. > > amd_cppc driver has 2 operation modes: autonomous (active) mode, > and non-autonomous (passive) mode. We register different CPUFreq driver > for different modes, "amd-cppc" for passive mode and "amd-cppc-epp" > for active mode. > > The passive mode leverages common governors such as *ondemand*, > *performance*, etc, to manage the performance tuning. While the active mode > uses epp to provides a hint to the hardware if software wants to bias > toward performance (0x0) or energy efficiency (0xff). CPPC power algorithm > in hardware will automatically calculate the runtime workload and adjust the > realtime cpu cores frequency according to the power supply and thermal, core > voltage and some other hardware conditions. > > amd-cppc is enabled on passive mode with a top-level `cpufreq=amd-cppc` > option, > while users add extra `active` flag to select active mode. > > With `cpufreq=amd-cppc,active`, we did a 60s sampling test to see the CPU > frequency change, through tweaking the energy_perf preference from > `xenpm set-cpufreq-cppc powersave` to `xenpm set-cpufreq-cppc performance`. > The outputs are as follows: > ``` > Setting CPU in powersave mode > Sampling and Outputs: > Avg freq 580000 KHz > Avg freq 580000 KHz > Avg freq 580000 KHz > Setting CPU in performance mode > Sampling and Outputs: > Avg freq 4640000 KHz > Avg freq 4220000 KHz > Avg freq 4640000 KHz > > Penny Zheng (18): > xen/cpufreq: guard perf.states[] access with XEN_PX_INIT > xen/cpufreq: move "init" flag into common structure > xen/cpufreq: extract _PSD info from "struct xen_processor_performance" > xen/cpufreq: introduce new sub-hypercall to propagate CPPC data > xen/cpufreq: refactor cmdline "cpufreq=xxx" > xen/cpufreq: introduce "cpufreq=amd-cppc" xen cmdline > xen/cpufreq: disable px statistic info in amd-cppc mode > xen/cpu: Expand core frequency calculation for AMD Family 1Ah CPUs > xen/amd: introduce amd_process_freq() to get processor frequency > xen/cpufreq: introduce a new amd cppc driver for cpufreq scaling > xen/cpufreq: implement EPP support for the amd-cppc driver in active > mode > xen/cpufreq: get performance policy from governor set via xenpm > xen/cpufreq: normalize hwp driver check with hwp_active() > xen/cpufreq: introduce GET_CPUFREQ_CPPC sub-cmd > xen/cpufreq: bypass governor-related para for amd-cppc-epp > tools: drop "has_num" condition check for cppc mode > tools: optimize cpufreq average freq print > xen/cpufreq: Adapt SET/GET_CPUFREQ_CPPC xen_sysctl_pm_op for amd-cppc > driver
As indicated in individual replies, three of the patches may be possible to go in before you re-post. Subject to what I said in the replies (patches 02, 08, and 13). Please clarify what (if anything) to do. Jan
