Re: perf: odd event scheduling issue

Peter Zijlstra
2015-05-20T15:25:43Z

On Wed, May 20, 2015 at 03:52:09PM +0200, Peter Zijlstra wrote:
> >
> > This patch limits the number of counters available to each CPU when
> > the HT bug workaround is enabled.
> >
> > This is necessary to avoid situation of counter starvation. Such can
> > arise from configuration where one HT thread, HT0, is using all 4 counters
> > with corrupting events which require exclusion the the sibling HT, HT1.
> >

>
> OK, so if you have the watchdog enabled, that's 1 event, and having a
> max of 2 GP events, adding another 2 events is fail.

Hmm, so we count all events, including those scheduled on fixed purpose
counters.

Lemme see if I can cure that.