Hi All, This series adds support for obtaining an average CPU frequency based on a hardware provided feedback. The average frequency is being exposed via dedicated yet optional cpufreq sysfs attribute - cpuinfo_avg_freq. The architecture specific bits are being provided for AArch64, caching on existing implementation for FIE and AMUv1 support: the frequency scale factor, updated on each sched tick, serving as a base for retrieving the frequency for a given CPU, representing an average frequency reported between the ticks. The changes have been rather lightly (due to some limitations) tested on an FVP model. Note that [PATCH 2/4] arm64: amu: Delay allocating cpumask for AMU FIE support can be merged independently. Additionally, this series depends on [6] Relevant discussions: [1] https://lore.kernel.org/all/20240229162520.970986-1-vanshikonda@xxxxxxxxxxxxxxxxxxxxxx/ [2] https://lore.kernel.org/all/7eozim2xnepacnnkzxlbx34hib4otycnbn4dqymfziqou5lw5u@5xzpv3t7sxo3/ [3] https://lore.kernel.org/all/20231212072617.14756-1-lihuisong@xxxxxxxxxx/ [4] https://lore.kernel.org/lkml/ZIHpd6unkOtYVEqP@xxxxxxxxxxxxxxxxxxxxxxxxx/T/#m4e74cb5a0aaa353c60fedc6cfb95ab7a6e381e3c [5] https://lore.kernel.org/all/20240603081331.3829278-1-beata.michalska@xxxxxxx/ [6] https://lore.kernel.org/all/20240827154818.1195849-1-ionela.voinescu@xxxxxxx/ v8: - Drop introducing new function and reuse arch_freq_get_on_cpu, guarding its use in scaling_cur_freq sysfs handler with dedicated config for x86 v7: - Dropping 'arch_topology: init capacity_freq_ref to 0' patch from the series as this one has been sent separately as an independent change [https://lore.kernel.org/all/20240827154818.1195849-1-ionela.voinescu@xxxxxxx/] - Including in the series change that introduces new sysfs entry [PATCH 1/4] - Consequently modifying previously arch_freq_get_on_cpu to match reqs for new sysfs attribute - Dropping an idea of considering a CPU that has been idle for a while as a valid source of information for obtaining an AMU-counter based frequency - Some minor cosmetic changes v6: - delay allocating cpumask for AMU FIE support instead of invalidating the mask upon failure to register cpufreq policy notifications - drop the change to cpufreq core (for cpuinfo_cur_freq) as this one will be sent as a separate change v5: - Fix invalid access to cpumask - Reworked finding reference cpu when getting the freq v4: - dropping seqcount - fixing identifying active cpu within given policy - skipping full dynticks cpus when retrieving the freq - bringing back plugging in arch_freq_get_on_cpu into cpuinfo_cur_freq v3: - dropping changes to cpufreq_verify_current_freq - pulling in changes from Ionela initializing capacity_freq_ref to 0 (thanks for that!) and applying suggestions made by her during last review: - switching to arch_scale_freq_capacity and arch_scale_freq_ref when reversing freq scale factor computation - swapping shift with multiplication - adding time limit for considering last scale update as valid - updating frequency scale factor upon entering idle v2: - Splitting the patches - Adding comment for full dyntick mode - Plugging arch_freq_get_on_cpu into cpufreq_verify_current_freq instead of in show_cpuinfo_cur_freq to allow the framework to stay more in sync with potential freq changes CC: Jonathan Corbet <corbet@xxxxxxx> CC: Thomas Gleixner <tglx@xxxxxxxxxxxxx> CC: Ingo Molnar <mingo@xxxxxxxxxx> CC: Borislav Petkov <bp@xxxxxxxxx> CC: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> CC: H. Peter Anvin <hpa@xxxxxxxxx> CC: Phil Auld <pauld@xxxxxxxxxx> CC: x86@xxxxxxxxxx CC: linux-doc@xxxxxxxxxxxxxxx Beata Michalska (4): cpufreq: Introduce an optional cpuinfo_avg_freq sysfs entry arm64: amu: Delay allocating cpumask for AMU FIE support arm64: Provide an AMU-based version of arch_freq_get_on_cpu arm64: Update AMU-based freq scale factor on entering idle Documentation/admin-guide/pm/cpufreq.rst | 16 ++- arch/arm64/kernel/topology.c | 144 +++++++++++++++++++---- arch/x86/kernel/cpu/aperfmperf.c | 2 +- arch/x86/kernel/cpu/proc.c | 7 +- drivers/cpufreq/Kconfig.x86 | 12 ++ drivers/cpufreq/cpufreq.c | 36 +++++- include/linux/cpufreq.h | 2 +- 7 files changed, 188 insertions(+), 31 deletions(-) -- 2.25.1
