On 21/01/25 14:14, Beata Michalska wrote:
Now that the frequency scale factor has been activated for retrieving
current frequency on a given CPU, trigger its update upon entering
idle. This will, to an extent, allow querying last known frequency
in a non-invasive way. It will also improve the frequency scale factor
accuracy when a CPU entering idle did not receive a tick for a while.
As a consequence, for idle cores, the reported frequency will be the
last one observed before entering the idle state.
Suggested-by: Vanshidhar Konda <vanshikonda@xxxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Beata Michalska <beata.michalska@xxxxxxx>
Reviewed-by: Sumit Gupta <sumitg@xxxxxxxxxx>
---
arch/arm64/kernel/topology.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c
index 5f5738b174c7..6c43aafac77c 100644
--- a/arch/arm64/kernel/topology.c
+++ b/arch/arm64/kernel/topology.c
@@ -213,6 +213,19 @@ static __always_inline bool amu_fie_cpu_supported(unsigned int cpu)
cpumask_test_cpu(cpu, amu_fie_cpus);
}
+void arch_cpu_idle_enter(void)
+{
+ unsigned int cpu = smp_processor_id();
+
+ if (!amu_fie_cpu_supported(cpu))
+ return;
+
+ /* Kick in AMU update but only if one has not happened already */
+ if (housekeeping_cpu(cpu, HK_TYPE_TICK) &&
+ time_is_before_jiffies(per_cpu(cpu_amu_samples.last_scale_update, cpu)))
+ amu_scale_freq_tick();
+}
+
#define AMU_SAMPLE_EXP_MS 20
int arch_freq_get_on_cpu(int cpu)
--
2.25.1
