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RE: [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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Re: [PATCH v2] Added perf functionality to mmdc driver Mark Rutland <mark.rutland@arm.com> - 2016-08-16 12:50 +0200
  Re: [PATCH v2] Added perf functionality to mmdc driver Peter Zijlstra <peterz@infradead.org> - 2016-08-16 14:10 +0200
  Re: [PATCH v2] Added perf functionality to mmdc driver Mark Rutland <mark.rutland@arm.com> - 2016-08-16 16:50 +0200
    RE: [PATCH v2] Added perf functionality to mmdc driver Zhengyu Shen <zhengyu.shen@nxp.com> - 2016-08-17 07:20 +0200
      Re: [PATCH v2] Added perf functionality to mmdc driver Mark Rutland <mark.rutland@arm.com> - 2016-08-17 12:10 +0200
  RE: [PATCH v2] Added perf functionality to mmdc driver Zhengyu Shen <zhengyu.shen@nxp.com> - 2016-08-16 19:20 +0200

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