[MODERATED] Re: [PATCH v3 2/6] PERFv3

[Andi Kleen <ak@linux.intel.com>]

On Fri, Feb 08, 2019 at 09:50:50AM +0100, speck for Peter Zijlstra wrote:
> On Thu, Feb 07, 2019 at 03:41:04PM -0800, speck for Andi Kleen wrote:
> > +static struct event_constraint *
> > +skl_get_event_constraints(struct cpu_hw_events *cpuc, int idx,
> > +			  struct perf_event *event)
> > +{
> > +	struct event_constraint *c;
> > +
> > +	c = hsw_get_event_constraints(cpuc, idx, event);
> > +
> > +	if (!perf_enable_all_counters) {
> > +		cpuc->counter3_constraint = *c;
> > +		c = &cpuc->counter3_constraint;
> > +
> > +		/*
> > +		 * Without TFA we must not use PMC3.
> > +		 */
> > +		__clear_bit(3, c->idxmsk);
> > +	}
> > +
> > +	return c;
> > +}
> 
> This is obviously broken... what if all 6 events are in use and have
> different constraints?

Don't understand the comment. Why 6? The intention is that if more
than 3 generic events are in use it will not schedule.

I tested this and it works.

-Andi