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SubjectRE: [PATCH V6 4/6] perf, x86: handle multiple records in PEBS buffer
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> >
> > A) the CTRn value reaches 0:
> > - the corresponding bit in GLOBAL_STATUS gets set
> > - we start arming the hardware assist
> >
> > < some unspecified amount of time later --
> > this could cover multiple events of interest >
> >
> > B) the hardware assist is armed, any next event will trigger it
> >
> > C) a matching event happens:
> > - the hardware assist triggers and generates a PEBS record
> > this includes a copy of GLOBAL_STATUS at this moment
> > - if we auto-reload we (re)set CTRn
>
> Is this actually true? Do we reload here or on A ?
>

Yes, on C.
According to SDM Volume 3, 18.7.1.1, the reset value will be
loaded after each PEBS record is written, which is done
by hw assist.


> > - we clear the relevant bit in GLOBAL_STATUS


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