perf parse-events: Add new "metric-id" term

Add a new "metric-id" term to events so that metric parsing can set an
ID that can be reliably looked up.

Metric parsing currently will turn a metric like "instructions/cycles"
into a parse events string of "{instructions,cycles}:W".

However, parse-events may change "instructions" into "instructions:u" if
perf_event_paranoid=2.

When this happens expr__resolve_id currently fails as stat-shadow adds
the ID "instructions:u" to match with the counter value and the metric
tries to look up the ID just "instructions".

A later patch will use the new term.

An example of the current problem:

  $ echo -1 > /proc/sys/kernel/perf_event_paranoid
  $ perf stat -M IPC /bin/true
   Performance counter stats for '/bin/true':

           1,217,161      inst_retired.any          #     0.97 IPC
           1,250,389      cpu_clk_unhalted.thread

         0.002064773 seconds time elapsed

         0.002378000 seconds user
         0.000000000 seconds sys

  $ echo 2 > /proc/sys/kernel/perf_event_paranoid
  $ perf stat -M IPC /bin/true
   Performance counter stats for '/bin/true':

             150,298      inst_retired.any:u        #      nan IPC
             187,095      cpu_clk_unhalted.thread:u

         0.002042731 seconds time elapsed

         0.000000000 seconds user
         0.002377000 seconds sys

Note: nan IPC is printed as an effect of "perf metric: Use NAN for
missing event IDs." but earlier versions of perf just fail with a parse
error and display no value.

Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Antonov <alexander.antonov@linux.intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrew Kilroy <andrew.kilroy@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Changbin Du <changbin.du@intel.com>
Cc: Denys Zagorui <dzagorui@cisco.com>
Cc: Fabian Hemmer <copy@copy.sh>
Cc: Felix Fietkau <nbd@nbd.name>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jacob Keller <jacob.e.keller@intel.com>
Cc: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Joakim Zhang <qiangqing.zhang@nxp.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Kees Kook <keescook@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Nicholas Fraser <nfraser@codeweavers.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Paul Clarke <pc@us.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Riccardo Mancini <rickyman7@gmail.com>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: ShihCheng Tu <mrtoastcheng@gmail.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Wan Jiabing <wanjiabing@vivo.com>
Cc: Zhen Lei <thunder.leizhen@huawei.com>
Link: https://lore.kernel.org/r/20211015172132.1162559-15-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index dbfeceb2546c..96ef6a4a7c14 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -410,6 +410,11 @@ struct evsel *evsel__clone(struct evsel *orig)
 		if (evsel->filter == NULL)
 			goto out_err;
 	}
+	if (orig->metric_id) {
+		evsel->metric_id = strdup(orig->metric_id);
+		if (evsel->metric_id == NULL)
+			goto out_err;
+	}
 	evsel->cgrp = cgroup__get(orig->cgrp);
 	evsel->tp_format = orig->tp_format;
 	evsel->handler = orig->handler;
@@ -779,6 +784,17 @@ out_unknown:
 	return "unknown";
 }
 
+const char *evsel__metric_id(const struct evsel *evsel)
+{
+	if (evsel->metric_id)
+		return evsel->metric_id;
+
+	if (evsel->core.attr.type == PERF_TYPE_SOFTWARE && evsel->tool_event)
+		return "duration_time";
+
+	return "unknown";
+}
+
 const char *evsel__group_name(struct evsel *evsel)
 {
 	return evsel->group_name ?: "anon group";
@@ -1423,6 +1439,7 @@ void evsel__exit(struct evsel *evsel)
 	zfree(&evsel->group_name);
 	zfree(&evsel->name);
 	zfree(&evsel->pmu_name);
+	zfree(&evsel->metric_id);
 	evsel__zero_per_pkg(evsel);
 	hashmap__free(evsel->per_pkg_mask);
 	evsel->per_pkg_mask = NULL;