Re: [PATCH v2 08/11] powerpc/perf: add support for the hv gpci (get performance counter info) interface

[Cody P Schafer]

On 02/24/2014 07:33 PM, Michael Ellerman wrote:
> On Fri, 2014-14-02 at 22:02:12 UTC, Cody P Schafer wrote:
> > This provides a basic link between perf and hv_gpci. Notably, it does
> > not yet support transactions and does not list any events (they can
> > still be manually composed).
>
> Can you explain how the HV_CAPS stuff ends up looking.
>
> I'm not against adding it, but I'd like to understand how we expect it to be
> used a bit better.

It's just a quick mechanism for me to expose some relevant information 
to userspace via sysfs using the hv_perf_caps_get() function's returned 
data. Documentation for this sysfs interface (and the rest) is in a 
later patch.
I don't expect any more uses to show up unless the firmware decides to 
add another capability bit (in which case I'll want to expose it as well).

> > diff --git a/arch/powerpc/perf/hv-gpci.c b/arch/powerpc/perf/hv-gpci.c
> > new file mode 100644
> > index 0000000..1f5d96d
> > --- /dev/null
> > +++ b/arch/powerpc/perf/hv-gpci.c
> > +
> > +static struct pmu h_gpci_pmu = {
> > +	.task_ctx_nr = perf_invalid_context,
> > +
> > +	.name = "hv_gpci",
> > +	.attr_groups = attr_groups,
> > +	.event_init  = h_gpci_event_init,
> > +	.add         = h_gpci_event_add,
> > +	.del         = h_gpci_event_del,
> 		     = h_gpci_event_stop,
>
> > +	.start       = h_gpci_event_start,
> > +	.stop        = h_gpci_event_stop,
> > +	.read        = h_gpci_event_read,
> 		     = h_gpci_event_update
>
> > +	.event_idx = perf_swevent_event_idx,
> > +};

whoops, thought I had fixed those 2 already.

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