Anshuman Khandual <khand...@linux.vnet.ibm.com> wrote:
> On 11/06/2012 07:23 AM, Michael Neuling wrote:
>
> > + if (!found && pvr_version_is(PVR_POWER7)) {
> > + /* check active counters for special buggy p7 overflow */
> > + for (i = 0; i < cpuhw->n_events; ++i) {
> > + event = cpuhw->event[i];
> > + if (!event->hw.idx || is_limited_pmc(event->hw.idx))
> > continue;
> > - val = read_pmc(i + 1);
> > - if (pmc_overflow(val))
> > - write_pmc(i + 1, 0);
> > + if (pmc_overflow_power7(val[event->hw.idx - 1])) {
>
>
> I have couple of questions.
>
> Can the buggy overflow happen on any of the available counters PMC1-PMC4 ?
No. It's limited to certain events and I believe it can only happen on
PMC2 and 4. This code doesn't bother trying to make this distinction
though.
> Will this approach never reset an actual user defined event (with
> sample period < 256) ? Is this related to the counter or the event
> which it is counting ? Just wondering if we have to do something more
> than checking for the count < 256. Just a thought.
I don't understand what you mean by these questions. Can you explain a
bit more?
Mikey
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