Re: [RFC PATCH 01/14] sched: track the runnable average on a per-taskentitiy basis

[Paul Turner]

On Thu, Feb 16, 2012 at 5:27 AM, Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> wrote:
> 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);

Ah-ha, good idea.  I had done some other fiddles to try and make
things fit better, but this will work.

Thanks!
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