Re: [RFC PATCH 01/14] sched: track the runnable average on aper-task entitiy basis

[Peter Zijlstra]

On Wed, 2012-02-01 at 17:38 -0800, Paul Turner wrote:
> +static __always_inline u64 decay_load(u64 val, int n)
> +{
> +       for (;n && val;n--) {
> +               val *= 4008;
> +               val >>= 12;
> +       }
> +
> +       return val;
> +}

> +                       sa->runnable_avg_sum =
> +                               decay_load(sa->runnable_avg_sum, 1);
> +                       sa->runnable_avg_period =
> +                               decay_load(sa->runnable_avg_period, 1); 

Since all you ever seem to do is:

  x = decay(x, n);

and frequently run over the line limits it might make sense to either
introduce a CPP helper or make the first argument a pointer and ditch
the return value so we end up with something like:

  decay(&x, n);


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