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SubjectRE: [PATCH v2] Added perf functionality to mmdc driver
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> > > > +	hrtimer_start(&pmu_mmdc->hrtimer, mmdc_timer_period(),
> > > > + HRTIMER_MODE_REL_PINNED);
> > >
> > > Why is a hrtimer necessary? Is this just copy-pasted from CCN, or do
> > > you have similar HW issues?
> > >
> > > Is there no overflow interrupt?
> >
> > When overflow occurs, a register bit is set to one. There is no
> > overflow interrupt which is why the timer is needed.
>
> I see. Please have add comment in the driver explaining this, so that this is
> obvious.
>
> Does the counter itself wrap and continue counting, or does it saturate?
>
> How have you tuned your polling period so as to avoid missing events in the
> case of an overflow?
>
> Thanks,
> Mark.
The counter wraps around once every ten seconds for total-cycles (which is the
Fastest increasing counter). Polling is done every one second just to be safe.

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