Re: [RFCv5 PATCH 01/46] arm: Frequency invariant scheduler load-tracking support

Vincent Guittot
2015-08-03T09:23:14Z

Hi Morten,

On 7 July 2015 at 20:23, Morten Rasmussen <morten.rasmussen@arm.com> wrote:
> From: Morten Rasmussen <Morten.Rasmussen@arm.com>
>

[snip]

> -
> #endif
> diff --git a/arch/arm/kernel/topology.c b/arch/arm/kernel/topology.c
> index 08b7847..9c09e6e 100644
> --- a/arch/arm/kernel/topology.c
> +++ b/arch/arm/kernel/topology.c
> @@ -169,6 +169,23 @@ static void update_cpu_capacity(unsigned int cpu)
> cpu, arch_scale_cpu_capacity(NULL, cpu));
> }
>
> +/*
> + * Scheduler load-tracking scale-invariance
> + *
> + * Provides the scheduler with a scale-invariance correction factor that
> + * compensates for frequency scaling (arch_scale_freq_capacity()). The scaling
> + * factor is updated in smp.c
> + */
> +unsigned long arm_arch_scale_freq_capacity(struct sched_domain *sd, int cpu)
> +{
> + unsigned long curr = atomic_long_read(&per_cpu(cpu_freq_capacity, cpu));

access to cpu_freq_capacity to should be put under #ifdef CONFIG_CPU_FREQ.

Why haven't you moved arm_arch_scale_freq_capacity in smp.c as
everything else for frequency in-variance is already in this file ?
This should also enable you to remove
DECLARE_PER_CPU(atomic_long_t, cpu_freq_capacity); from topology.h

Vincent

> +
> + if (!curr)
> + return SCHED_CAPACITY_SCALE;
> +
> + return curr;
> +}
> +
> #else
> static inline void parse_dt_topology(void) {}
> static inline void update_cpu_capacity(unsigned int cpuid) {}
> --
> 1.9.1
>