Re: [PATCH 2/4] perf: Add filter_match() as a parameter for pinned/flexible_sched_in()

[Liang, Kan]

On 4/29/2019 11:12 AM, Mark Rutland wrote:
> On Mon, Apr 29, 2019 at 07:44:03AM -0700, kan.liang@xxxxxxxxxxxxxxx wrote:
> > From: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
> >
> > A fast path will be introduced in the following patches to speed up the
> > cgroup events sched in, which only needs a simpler filter_match().
> >
> > Add filter_match() as a parameter for pinned/flexible_sched_in().
> >
> > No functional change.
>
> I suspect that the cost you're trying to avoid is pmu_filter_match()
> iterating over the entire group, which arm systems rely upon for correct
> behaviour on big.LITTLE systems.
>
> Is that the case?

No. In X86, we don't use pmu_filter_match(). The fast path still keeps 
this filter.
perf_cgroup_match() is the one I want to avoid.

Thanks,
Kan

> Thanks,
> Mark.
>
> > Signed-off-by: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
> > ---
> >   kernel/events/core.c | 15 +++++++++------
> >   1 file changed, 9 insertions(+), 6 deletions(-)
> >
> > diff --git a/kernel/events/core.c b/kernel/events/core.c
> > index 388dd42..782fd86 100644
> > --- a/kernel/events/core.c
> > +++ b/kernel/events/core.c
> > @@ -3251,7 +3251,8 @@ static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
> >   }
> >   
> >   static int visit_groups_merge(struct perf_event_groups *groups, int cpu,
> > -			      int (*func)(struct perf_event *, void *), void *data)
> > +			      int (*func)(struct perf_event *, void *, int (*)(struct perf_event *)),
> > +			      void *data)
> >   {
> >   	struct perf_event **evt, *evt1, *evt2;
> >   	int ret;
> > @@ -3271,7 +3272,7 @@ static int visit_groups_merge(struct perf_event_groups *groups, int cpu,
> >   			evt = &evt2;
> >   		}
> >   
> > -		ret = func(*evt, data);
> > +		ret = func(*evt, data, event_filter_match);
> >   		if (ret)
> >   			return ret;
> >   
> > @@ -3287,7 +3288,8 @@ struct sched_in_data {
> >   	int can_add_hw;
> >   };
> >   
> > -static int pinned_sched_in(struct perf_event *event, void *data)
> > +static int pinned_sched_in(struct perf_event *event, void *data,
> > +			   int (*filter_match)(struct perf_event *))
> >   {
> >   	struct sched_in_data *sid = data;
> >   
> > @@ -3300,7 +3302,7 @@ static int pinned_sched_in(struct perf_event *event, void *data)
> >   		return 0;
> >   #endif
> >   
> > -	if (!event_filter_match(event))
> > +	if (!filter_match(event))
> >   		return 0;
> >   
> >   	if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
> > @@ -3318,7 +3320,8 @@ static int pinned_sched_in(struct perf_event *event, void *data)
> >   	return 0;
> >   }
> >   
> > -static int flexible_sched_in(struct perf_event *event, void *data)
> > +static int flexible_sched_in(struct perf_event *event, void *data,
> > +			     int (*filter_match)(struct perf_event *))
> >   {
> >   	struct sched_in_data *sid = data;
> >   
> > @@ -3331,7 +3334,7 @@ static int flexible_sched_in(struct perf_event *event, void *data)
> >   		return 0;
> >   #endif
> >   
> > -	if (!event_filter_match(event))
> > +	if (!filter_match(event))
> >   		return 0;
> >   
> >   	if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) {
> > --
> > 2.7.4