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SubjectRe: [perfmon2] [announce] Performance Counters for Linux, v6

* Luck, Tony <tony.luck@intel.com> wrote:

> > - or the PMU capability is expressed as a special counter type (if it's
> > useful enough) - and then either the write() method or ioctl is extended
> > to express attributes we want to set/change while a counter is running.
>
> The product of:
> {exotic PMU modes} * {creative performance measurement ideas}
>
> will produce a large number of candidates for these special counters (at
> least on ia64 ... which has a large number of exotic PMU options).
>
> I don't think that I'm qualified to judge which of them are "useful
> enough" to warrant a special counter type.

it should certainly be done on a case by case basis. They need to be
consciously exposed not just summarily exported to user-space, because PMU
hw features have security implications so it has to be done all
explicitly.

Ingo


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