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authorVincent Guittot <vincent.guittot@linaro.org>2023-12-11 13:48:49 +0300
committerIngo Molnar <mingo@kernel.org>2023-12-23 17:52:34 +0300
commit9942cb22ea458c34fa17b73d143ea32d4df1caca (patch)
tree58b4f5b66b9156339b07eabfe8933dff8427c125 /include/linux/sched
parentd2e9f53ac5dd76dadc0b5f04f6c27640604ce2af (diff)
downloadlinux-9942cb22ea458c34fa17b73d143ea32d4df1caca.tar.xz
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 <vincent.guittot@linaro.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Tested-by: Lukasz Luba <lukasz.luba@arm.com> Reviewed-by: Lukasz Luba <lukasz.luba@arm.com> Acked-by: Sudeep Holla <sudeep.holla@arm.com> Link: https://lore.kernel.org/r/20231211104855.558096-2-vincent.guittot@linaro.org
Diffstat (limited to 'include/linux/sched')
-rw-r--r--include/linux/sched/topology.h8
1 files changed, 8 insertions, 0 deletions
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));