Re: [PATCH v2] perfcounters: record time running and time enabled for each counter

[Ingo Molnar <mingo@elte.hu>]

* Andrew Morton <akpm@linux-foundation.org> wrote:

> > @@ -243,6 +259,8 @@ struct perf_counter {
> >  
> >  	struct perf_counter		*parent;
> >  	struct list_head		child_list;
> > +	atomic64_t			child_time_enabled;
> > +	atomic64_t			child_time_running;
> 
> These read like booleans, but why are they atomic64_t's?

for inherited counters these values get collected back into a 
'parent counter' in a lockless way - hence to not lose statistics on 
SMP they need to be atomic64_t.

> > @@ -290,6 +308,8 @@ struct perf_counter_context {
> >  	int			nr_active;
> >  	int			is_active;
> >  	struct task_struct	*task;
> > +	u64			time_now;
> > +	u64			time_lost;
> >  #endif
> >  };
> 
> I don't have a copy of this header file handy, but from the 
> snippet I see here, it doesn't look as though it is as clear and 
> as understadable as we can possibly make it?

i'll post the latest perfcounters tree - it's time for that anyway.

	Ingo