Re: [PATCH v5 2/7] perf evlist: Add evlist__findnew_tracking_event() helper

[Adrian Hunter]

On 4/08/23 05:07, Yang Jihong wrote:
> Currently, intel-bts, intel-pt, and arm-spe may add a dummy event for
> tracking to the evlist. We may need to search for the dummy event for
> some settings. Therefore, add evlist__findnew_tracking_event() helper.
> 
> evlist__findnew_tracking_event() also deal with system_wide maps if
> system_wide is true.
> 
> Signed-off-by: Yang Jihong <yangjihong1@xxxxxxxxxx>

Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>

> ---
>  tools/perf/builtin-record.c | 11 +++--------
>  tools/perf/util/evlist.c    | 18 ++++++++++++++++++
>  tools/perf/util/evlist.h    |  1 +
>  3 files changed, 22 insertions(+), 8 deletions(-)
> 
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index aec18db7ff23..ca83599cc50c 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -1295,14 +1295,9 @@ static int record__open(struct record *rec)
>  	 */
>  	if (opts->target.initial_delay || target__has_cpu(&opts->target) ||
>  	    perf_pmus__num_core_pmus() > 1) {
> -		pos = evlist__get_tracking_event(evlist);
> -		if (!evsel__is_dummy_event(pos)) {
> -			/* Set up dummy event. */
> -			if (evlist__add_dummy(evlist))
> -				return -ENOMEM;
> -			pos = evlist__last(evlist);
> -			evlist__set_tracking_event(evlist, pos);
> -		}
> +		pos = evlist__findnew_tracking_event(evlist, false);
> +		if (!pos)
> +			return -ENOMEM;
>  
>  		/*
>  		 * Enable the dummy event when the process is forked for
> diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
> index 7ef43f72098e..25c3ebe2c2f5 100644
> --- a/tools/perf/util/evlist.c
> +++ b/tools/perf/util/evlist.c
> @@ -1694,6 +1694,24 @@ void evlist__set_tracking_event(struct evlist *evlist, struct evsel *tracking_ev
>  	tracking_evsel->tracking = true;
>  }
>  
> +struct evsel *evlist__findnew_tracking_event(struct evlist *evlist, bool system_wide)
> +{
> +	struct evsel *evsel;
> +
> +	evsel = evlist__get_tracking_event(evlist);
> +	if (!evsel__is_dummy_event(evsel)) {
> +		evsel = evlist__add_aux_dummy(evlist, system_wide);
> +		if (!evsel)
> +			return NULL;
> +
> +		evlist__set_tracking_event(evlist, evsel);
> +	} else if (system_wide) {
> +		perf_evlist__go_system_wide(&evlist->core, &evsel->core);
> +	}
> +
> +	return evsel;
> +}
> +
>  struct evsel *evlist__find_evsel_by_str(struct evlist *evlist, const char *str)
>  {
>  	struct evsel *evsel;
> diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
> index 664c6bf7b3e0..98e7ddb2bd30 100644
> --- a/tools/perf/util/evlist.h
> +++ b/tools/perf/util/evlist.h
> @@ -387,6 +387,7 @@ bool evlist_cpu_iterator__end(const struct evlist_cpu_iterator *evlist_cpu_itr);
>  
>  struct evsel *evlist__get_tracking_event(struct evlist *evlist);
>  void evlist__set_tracking_event(struct evlist *evlist, struct evsel *tracking_evsel);
> +struct evsel *evlist__findnew_tracking_event(struct evlist *evlist, bool system_wide);
>  
>  struct evsel *evlist__find_evsel_by_str(struct evlist *evlist, const char *str);
>