On Fri, May 22, 2015 at 03:08:44PM +0100, Will Deacon wrote: > Hi Mark, > > On Wed, May 13, 2015 at 05:12:23PM +0100, Mark Rutland wrote: > > In certain circumstances it may not be possible to schedule particular > > events due to constraints other than a lack of hardware counters (e.g. > > on big.LITTLE systems where CPUs support different events). The core > > perf event code does not distinguish these cases and pessimistically > > assumes that any failure to schedule an event means that it is not worth > > attempting to schedule later events, even if some hardware counters are > > still unused. > > > > When an event a pmu cannot schedule exists in a flexible group list it > > can unnecessarily prevent event groups following it in the list from > > being scheduled (until it is rotated to the end of the list). This means > > some events are scheduled for only a portion of the time they could be, > > and for short running programs no events may be scheduled if the list is > > initially sorted in an unfortunate order. > > > > This patch adds a new (optional) filter_match function pointer to struct > > pmu which a pmu driver can use to tell perf core when an event matches > > pmu-specific scheduling requirements. This plugs into the existing > > event_filter_match logic, and makes it possible to avoid the scheduling > > problem described above. When no filter is provided by the PMU, the > > existing behaviour is retained. > > > > Signed-off-by: Mark Rutland <[email protected]> > > Acked-by: Will Deacon <[email protected]> > > Cc: Peter Zijlstra <[email protected]> > > Cc: Paul Mackerras <[email protected]> > > Cc: Ingo Molnar <[email protected]> > > Cc: Arnaldo Carvalho de Melo <[email protected]> > > --- > > include/linux/perf_event.h | 5 +++++ > > kernel/events/core.c | 8 +++++++- > > 2 files changed, 12 insertions(+), 1 deletion(-) > > Whilst I'm really keen to merge the architecture-specific parts of this > series, I'm going to need an Ack from one of the perf core maintainers > on this patch. > > Peter, can you take a look please? (and I assume this is self-contained > enough not to conflict heavily with the current perf queue?).
Acked-by: Peter Zijlstra (Intel) <[email protected]> Merge it however you like, but test merge against tip/perf/core or something of that nature, if a conflict pops up, maybe keep this one patch in a separate branch such that it can also be pulled into tip/perf/core -- but as you say, I don't really suspect a conflict. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
