From 9942cb22ea458c34fa17b73d143ea32d4df1caca Mon Sep 17 00:00:00 2001 From: Vincent Guittot Date: Mon, 11 Dec 2023 11:48:49 +0100 Subject: sched/topology: Add a new arch_scale_freq_ref() method Create a new method to get a unique and fixed max frequency. Currently cpuinfo.max_freq or the highest (or last) state of performance domain are used as the max frequency when computing the frequency for a level of utilization, but: - cpuinfo_max_freq can change at runtime. boost is one example of such change. - cpuinfo.max_freq and last item of the PD can be different leading to different results between cpufreq and energy model. We need to save the reference frequency that has been used when computing the CPUs capacity and use this fixed and coherent value to convert between frequency and CPU's capacity. In fact, we already save the frequency that has been used when computing the capacity of each CPU. We extend the precision to save kHz instead of MHz currently and we modify the type to be aligned with other variables used when converting frequency to capacity and the other way. [ mingo: Minor edits. ] Signed-off-by: Vincent Guittot Signed-off-by: Ingo Molnar Tested-by: Lukasz Luba Reviewed-by: Lukasz Luba Acked-by: Sudeep Holla Link: https://lore.kernel.org/r/20231211104855.558096-2-vincent.guittot@linaro.org --- include/linux/arch_topology.h | 7 +++++++ include/linux/sched/topology.h | 8 ++++++++ 2 files changed, 15 insertions(+) (limited to 'include') diff --git a/include/linux/arch_topology.h b/include/linux/arch_topology.h index a07b510e7dc5..32c24ff4f2a8 100644 --- a/include/linux/arch_topology.h +++ b/include/linux/arch_topology.h @@ -27,6 +27,13 @@ static inline unsigned long topology_get_cpu_scale(int cpu) void topology_set_cpu_scale(unsigned int cpu, unsigned long capacity); +DECLARE_PER_CPU(unsigned long, capacity_freq_ref); + +static inline unsigned long topology_get_freq_ref(int cpu) +{ + return per_cpu(capacity_freq_ref, cpu); +} + DECLARE_PER_CPU(unsigned long, arch_freq_scale); static inline unsigned long topology_get_freq_scale(int cpu) diff --git a/include/linux/sched/topology.h b/include/linux/sched/topology.h index de545ba85218..a6e04b4a21d7 100644 --- a/include/linux/sched/topology.h +++ b/include/linux/sched/topology.h @@ -279,6 +279,14 @@ void arch_update_thermal_pressure(const struct cpumask *cpus, { } #endif +#ifndef arch_scale_freq_ref +static __always_inline +unsigned int arch_scale_freq_ref(int cpu) +{ + return 0; +} +#endif + static inline int task_node(const struct task_struct *p) { return cpu_to_node(task_cpu(p)); -- cgit v1.2.3