| Message ID | 20250121084435.2839280-6-beata.michalska@arm.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Add support for AArch64 AMUv1-based average freq | expand |
On 21-01-2025 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@os.amperecomputing.com> > Signed-off-by: Beata Michalska <beata.michalska@arm.com> > --- > 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) Looks good to me. Reviewed-by: Prasanna Kumar T S M <ptsm@linux.microsoft.com>
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)
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@os.amperecomputing.com> Signed-off-by: Beata Michalska <beata.michalska@arm.com> --- arch/arm64/kernel/topology.c | 13 +++++++++++++ 1 file changed, 13 insertions(+)