Re: PAPI pmda Note

[fche@xxxxxxxxxx (Frank Ch. Eigler)]

Nathan Scott <nathans@xxxxxxxxxx> writes:

> [...]  OOC, is it possible to ask PAPI what hardware counters are
> enabled?  (IOW, without relying on the state kept in-memory, in the
> daemon, as a result of changes it made itself, but rather by asking
> the hardware/kernel?).

No - the kernel keeps that info to itself, and multiplexes amongst
applications and its own internal usage.


> If so, that would be great to use as the value for the control "enable"
> metric, 

(I've nudged lberk toward using the ".status" read-only metric as a
better-colored toolshed to describe current state.)

> instead of simply exporting whatever state changes we've made in the
> PMDA (and assuming everything was disabled when it started, which
> may not have been the case). [...]

(I've nudged lberk toward not making ".enable"/".disable" readable at
all, especially if they are to return merely the most-recent deltas
rather than the cumulative situation.)


- FChE