Commit 7398bf18 authored by Kan Liang's avatar Kan Liang Committed by Arnaldo Carvalho de Melo
Browse files

perf evsel: Assign abbr name for the branch counter events 



There could be several branch counter events. If perf tool output the
result via the format "event name + a number", the line could be very
long and hard to read.

An abbreviation is introduced to replace the full event name in the
display. The abbreviation starts from 'A' to 'Z9', which can support
up to 286 events. The same abbreviation will be assigned if the same
events are found in the evlist. The next patch will utilize the
abbreviation name to show the branch counter events in the output.

Reviewed-by: default avatarAndi Kleen <ak@linux.intel.com>
Signed-off-by: default avatarKan Liang <kan.liang@linux.intel.com>
Acked-by: default avatarNamhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: https://lore.kernel.org/r/20240813160208.2493643-6-kan.liang@linux.intel.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 1f2b7fbb

tools/perf/util/evlist.c

+54 −1
Original line number Diff line number Diff line
@@ -33,6 +33,7 @@ 
#include "util/bpf-filter.h"

#include "util/stat.h"

#include "util/util.h"

#include "util/env.h"

#include "util/intel-tpebs.h"

#include <signal.h>

#include <unistd.h>
@@ -1265,15 +1266,67 @@ u64 evlist__combined_branch_type(struct evlist *evlist) 
	return branch_type;

}



static struct evsel *

evlist__find_dup_event_from_prev(struct evlist *evlist, struct evsel *event)

{

	struct evsel *pos;



	evlist__for_each_entry(evlist, pos) {

		if (event == pos)

			break;

		if ((pos->core.attr.branch_sample_type & PERF_SAMPLE_BRANCH_COUNTERS) &&

		    !strcmp(pos->name, event->name))

			return pos;

	}

	return NULL;

}



#define MAX_NR_ABBR_NAME	(26 * 11)



/*

 * The abbr name is from A to Z9. If the number of event

 * which requires the branch counter > MAX_NR_ABBR_NAME,

 * return NA.

 */

static void evlist__new_abbr_name(char *name)

{

	static int idx;

	int i = idx / 26;



	if (idx >= MAX_NR_ABBR_NAME) {

		name[0] = 'N';

		name[1] = 'A';

		name[2] = '\0';

		return;

	}



	name[0] = 'A' + (idx % 26);



	if (!i)

		name[1] = '\0';

	else {

		name[1] = '0' + i - 1;

		name[2] = '\0';

	}



	idx++;

}



void evlist__update_br_cntr(struct evlist *evlist)

{

	struct evsel *evsel;

	struct evsel *evsel, *dup;

	int i = 0;



	evlist__for_each_entry(evlist, evsel) {

		if (evsel->core.attr.branch_sample_type & PERF_SAMPLE_BRANCH_COUNTERS) {

			evsel->br_cntr_idx = i++;

			evsel__leader(evsel)->br_cntr_nr++;



			dup = evlist__find_dup_event_from_prev(evlist, evsel);

			if (dup)

				memcpy(evsel->abbr_name, dup->abbr_name, 3 * sizeof(char));

			else

				evlist__new_abbr_name(evsel->abbr_name);

		}

	}

	evlist->nr_br_cntr = i;

tools/perf/util/evsel.h

+6 −0
Original line number Diff line number Diff line
@@ -153,9 +153,15 @@ struct evsel { 
	 * br_cntr_idx: The idx of the branch counter event in the evlist

	 * br_cntr_nr:  The number of the branch counter event in the group

	 *	        (Only available for the leader event)

	 * abbr_name:   The abbreviation name assigned to an event which is

	 *		logged by the branch counter.

	 *		The abbr name is from A to Z9. NA is applied if out

	 *		of the range.

	 */

	int			br_cntr_idx;

	int			br_cntr_nr;

	char			abbr_name[3];



	/*

	 * bpf_counter_ops serves two use cases:

	 *   1. perf-stat -b          counting events used byBPF programs