Re: [RFC] perf_sample_id::idx

[Arnaldo Carvalho de Melo]

Em Fri, Aug 09, 2019 at 03:20:14PM +0000, Hunter, Adrian escreveu:

> It will be used for AUX area sampling.  A sample will have AUX area
> data that will be queued for decoding, where there are separate queues
> for each CPU (per-cpu tracing) or task (per-thread tracing).  The
> sample ID can be used to lookup 'idx' which is effectively the queue
> number.

Would be good to have this as a comment in the perf_sample_id struct
definition :-)

- Arnaldo
 
> > -----Original Message-----
> > From: Jiri Olsa [mailto:jolsa@xxxxxxxxxx]
> > Sent: Friday, August 9, 2019 12:28 PM
> > To: Hunter, Adrian <adrian.hunter@xxxxxxxxx>
> > Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>; Ingo Molnar
> > <mingo@xxxxxxxxxx>; Namhyung Kim <namhyung@xxxxxxxxxx>; Alexander
> > Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>; Peter Zijlstra
> > <a.p.zijlstra@xxxxxxxxx>; Michael Petlan <mpetlan@xxxxxxxxxx>; linux-
> > kernel@xxxxxxxxxxxxxxx
> > Subject: [RFC] perf_sample_id::idx
> > 
> > hi,
> > what's the perf_sample_id::idx for? It was added in here:
> >   3c659eedada2 perf tools: Add id index
> > 
> > but I dont see any practical usage of it in the sources, when I remove it like
> > below, I get clean build
> > 
> > any idea?
> > 
> > thanks,
> > jirka
> > 
> > 
> > ---
> > diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h index
> > 70841d115349..24b90f68d616 100644
> > --- a/tools/perf/util/event.h
> > +++ b/tools/perf/util/event.h
> > @@ -498,7 +498,7 @@ struct tracing_data_event {
> > 
> >  struct id_index_entry {
> >  	u64 id;
> > -	u64 idx;
> > +	u64 idx; /* deprecated */
> >  	u64 cpu;
> >  	u64 tid;
> >  };
> > diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c index
> > c4489a1ad6bc..e55133cacb64 100644
> > --- a/tools/perf/util/evlist.c
> > +++ b/tools/perf/util/evlist.c
> > @@ -519,11 +519,11 @@ int perf_evlist__id_add_fd(struct evlist *evlist,  }
> > 
> >  static void perf_evlist__set_sid_idx(struct evlist *evlist,
> > -				     struct evsel *evsel, int idx, int cpu,
> > +				     struct evsel *evsel, int cpu,
> >  				     int thread)
> >  {
> >  	struct perf_sample_id *sid = SID(evsel, cpu, thread);
> > -	sid->idx = idx;
> > +
> >  	if (evlist->core.cpus && cpu >= 0)
> >  		sid->cpu = evlist->core.cpus->map[cpu];
> >  	else
> > @@ -795,8 +795,7 @@ static int perf_evlist__mmap_per_evsel(struct evlist
> > *evlist, int idx,
> >  			if (perf_evlist__id_add_fd(evlist, evsel, cpu, thread,
> >  						   fd) < 0)
> >  				return -1;
> > -			perf_evlist__set_sid_idx(evlist, evsel, idx, cpu,
> > -						 thread);
> > +			perf_evlist__set_sid_idx(evlist, evsel, cpu, thread);
> >  		}
> >  	}
> > 
> > diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h index
> > 3cf35aa782b9..b9d864933d75 100644
> > --- a/tools/perf/util/evsel.h
> > +++ b/tools/perf/util/evsel.h
> > @@ -23,7 +23,6 @@ struct perf_sample_id {
> >  	struct hlist_node 	node;
> >  	u64		 	id;
> >  	struct evsel		*evsel;
> > -	int			idx;
> >  	int			cpu;
> >  	pid_t			tid;
> > 
> > diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c index
> > b9fe71d11bf6..2642d60aa875 100644
> > --- a/tools/perf/util/session.c
> > +++ b/tools/perf/util/session.c
> > @@ -2394,7 +2394,6 @@ int perf_event__process_id_index(struct
> > perf_session *session,
> >  		sid = perf_evlist__id2sid(evlist, e->id);
> >  		if (!sid)
> >  			return -ENOENT;
> > -		sid->idx = e->idx;
> >  		sid->cpu = e->cpu;
> >  		sid->tid = e->tid;
> >  	}
> > @@ -2454,7 +2453,7 @@ int perf_event__synthesize_id_index(struct
> > perf_tool *tool,
> >  				return -ENOENT;
> >  			}
> > 
> > -			e->idx = sid->idx;
> > +			e->idx = -1;
> >  			e->cpu = sid->cpu;
> >  			e->tid = sid->tid;
> >  		}

-- 

- Arnaldo