| From | "Rafael J. Wysocki" <> | Date | Tue, 19 Apr 2022 18:30:45 +0200 | Subject | Re: [patch 08/10] x86/aperfmperf: Store aperf/mperf data for cpu frequency reads |
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On Fri, Apr 15, 2022 at 9:20 PM Thomas Gleixner <tglx@linutronix.de> wrote: > > Now that the MSR readout is unconditional, store the results in the per CPU > data structure along with a jiffies timestamp for the CPU frequency readout > code. > > Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> --- > arch/x86/kernel/cpu/aperfmperf.c | 14 +++++++++++++- > 1 file changed, 13 insertions(+), 1 deletion(-) > > --- a/arch/x86/kernel/cpu/aperfmperf.c > +++ b/arch/x86/kernel/cpu/aperfmperf.c > @@ -24,11 +24,17 @@ > #include "cpu.h" > > struct aperfmperf { > + seqcount_t seq; > + unsigned long last_update; > + u64 acnt; > + u64 mcnt; > u64 aperf; > u64 mperf; > }; > > -static DEFINE_PER_CPU_SHARED_ALIGNED(struct aperfmperf, cpu_samples); > +static DEFINE_PER_CPU_SHARED_ALIGNED(struct aperfmperf, cpu_samples) = { > + .seq = SEQCNT_ZERO(cpu_samples.seq) > +}; > > struct aperfmperf_sample { > unsigned int khz; > @@ -515,6 +521,12 @@ void arch_scale_freq_tick(void) > s->aperf = aperf; > s->mperf = mperf; > > + raw_write_seqcount_begin(&s->seq); > + s->last_update = jiffies; > + s->acnt = acnt; > + s->mcnt = mcnt; > + raw_write_seqcount_end(&s->seq); > + > scale_freq_tick(acnt, mcnt); > } > >
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