From 39b19974982e03bd7b950f33bc0855385845c9fb Mon Sep 17 00:00:00 2001 From: Beata Michalska Date: Fri, 31 Jan 2025 16:24:39 +0000 Subject: [PATCH] arm64: Update AMU-based freq scale factor on entering idle 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 Signed-off-by: Beata Michalska Reviewed-by: Prasanna Kumar T S M Reviewed-by: Sumit Gupta Link: https://lore.kernel.org/r/20250131162439.3843071-5-beata.michalska@arm.com Signed-off-by: Catalin Marinas --- 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 28fb004d3103..a09b0551ec59 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)