Proposed systemtap access to perfmon hardware

[Frank Ch. Eigler]

Hi -

wcohen wrote:
> [...]
> > [...]
> > Is that sufficiently detailed to begin an implementation?
>
> Pretty close. The one thing that isn't answered is the division of
> the labor for the sampling probes, onetime setup vs sample handler.
> [...]

In other words, the issue is the desire to control sampling-event-type
counters, not just the free-running counters.  In this case, one might
use both ".setup" and ".sample" probes for the same SPEC:

# probe perfctr.SPEC.setup { h = $handle }
# probe perfctr.SPEC.sample(1234) { /* like timer.profile */ }
# probe ANY { ... perfctr_{start,stop,query} (h) ... }

- FChE