Re: [patch 06/10] x86/aperfmperf: Restructure arch_scale_freq_tick()

Rafael J. Wysocki
2022-04-19T16:20:33Z

On Fri, Apr 15, 2022 at 9:20 PM Thomas Gleixner <tglx@linutronix.de> wrote:
>
> Preparation for sharing code with the CPU frequency portion of the
> aperf/mperf code.
>
> No functional change.
>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

All good AFAICS:

Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

> ---
> arch/x86/kernel/cpu/aperfmperf.c | 36 +++++++++++++++++++++---------------
> 1 file changed, 21 insertions(+), 15 deletions(-)
>
> --- a/arch/x86/kernel/cpu/aperfmperf.c
> +++ b/arch/x86/kernel/cpu/aperfmperf.c
> @@ -477,22 +477,9 @@ static DECLARE_WORK(disable_freq_invaria
>
> DEFINE_PER_CPU(unsigned long, arch_freq_scale) = SCHED_CAPACITY_SCALE;
>
> -void arch_scale_freq_tick(void)
> +static void scale_freq_tick(u64 acnt, u64 mcnt)
> {
> - struct aperfmperf *s = this_cpu_ptr(&cpu_samples);
> - u64 aperf, mperf, acnt, mcnt, freq_scale;
> -
> - if (!arch_scale_freq_invariant())
> - return;
> -
> - rdmsrl(MSR_IA32_APERF, aperf);
> - rdmsrl(MSR_IA32_MPERF, mperf);
> -
> - acnt = aperf - s->aperf;
> - mcnt = mperf - s->mperf;
> -
> - s->aperf = aperf;
> - s->mperf = mperf;
> + u64 freq_scale;
>
> if (check_shl_overflow(acnt, 2*SCHED_CAPACITY_SHIFT, &acnt))
> goto error;
> @@ -514,4 +501,23 @@ void arch_scale_freq_tick(void)
> pr_warn("Scheduler frequency invariance went wobbly, disabling!\n");
> schedule_work(&disable_freq_invariance_work);
> }
> +
> +void arch_scale_freq_tick(void)
> +{
> + struct aperfmperf *s = this_cpu_ptr(&cpu_samples);
> + u64 acnt, mcnt, aperf, mperf;
> +
> + if (!arch_scale_freq_invariant())
> + return;
> +
> + rdmsrl(MSR_IA32_APERF, aperf);
> + rdmsrl(MSR_IA32_MPERF, mperf);
> + acnt = aperf - s->aperf;
> + mcnt = mperf - s->mperf;
> +
> + s->aperf = aperf;
> + s->mperf = mperf;
> +
> + scale_freq_tick(acnt, mcnt);
> +}
> #endif /* CONFIG_X86_64 && CONFIG_SMP */
>