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SubjectRe: [RFC/RFT][PATCH v5] cpuidle: New timer events oriented governor for tickless systems
Date
On Sunday, November 11, 2018 4:20:34 PM CET Peter Zijlstra wrote:
> On Thu, Nov 08, 2018 at 06:25:07PM +0100, Rafael J. Wysocki wrote:
> > +/*
> > + * The SPIKE value is added to metrics when they grow and the DECAY_SHIFT value
> > + * is used for decreasing metrics on a regular basis.
> > + */
> > +#define SPIKE 1024
> > +#define DECAY_SHIFT 3
>
> > + if (idx_timer >= 0) {
> > + unsigned int hits = cpu_data->states[idx_timer].hits;
> > + unsigned int misses = cpu_data->states[idx_timer].misses;
> > +
> > + hits -= hits >> DECAY_SHIFT;
> > + misses -= misses >> DECAY_SHIFT;
> > +
> > + if (idx_timer > idx_hit) {
> > + misses += SPIKE;
> > + if (idx_hit >= 0)
> > + cpu_data->states[idx_hit].early_hits += SPIKE;
> > + } else {
> > + hits += SPIKE;
> > + }
> > +
> > + cpu_data->states[idx_timer].misses = misses;
> > + cpu_data->states[idx_timer].hits = hits;
> > + }
>
> That's a pulse-density-modulator, with a signal bound of:
>
> 1024 == x/8 -> x := 8192
>
> Anyway; I would suggest s/SPIKE/PULSE/ because of that.

OK


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