perf parse-events: Warn if a cpu term is unsupported by a CPU

Factor requested CPU warning out of evlist and into evsel. At the end
of adding an event, perform the warning check. To avoid repeatedly
testing if the cpu_list is empty, add a local variable.

```
$ perf stat -e cpu_atom/cycles,cpu=1/ -a true
WARNING: A requested CPU in '1' is not supported by PMU 'cpu_atom' (CPUs 16-27) for event 'cpu_atom/cycles/'

 Performance counter stats for 'system wide':

   <not supported>      cpu_atom/cycles/

       0.000781511 seconds time elapsed
```

Reviewed-by: Thomas Falcon <thomas.falcon@intel.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: James Clark <james.clark@linaro.org>
Link: https://lore.kernel.org/r/20250719030517.1990983-2-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 995ad5f654d073190472d8c1705d45b2f5b8106f..80d8387e6b97bcdf1af6146b21c048467d0f7a9a 100644 (file)
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -2549,20 +2549,7 @@ void evlist__warn_user_requested_cpus(struct evlist *evlist, const char *cpu_lis
                return;
 
        evlist__for_each_entry(evlist, pos) {
-               struct perf_cpu_map *intersect, *to_test, *online = cpu_map__online();
-               const struct perf_pmu *pmu = evsel__find_pmu(pos);
-
-               to_test = pmu && pmu->is_core ? pmu->cpus : online;
-               intersect = perf_cpu_map__intersect(to_test, user_requested_cpus);
-               if (!perf_cpu_map__equal(intersect, user_requested_cpus)) {
-                       char buf[128];
-
-                       cpu_map__snprint(to_test, buf, sizeof(buf));
-                       pr_warning("WARNING: A requested CPU in '%s' is not supported by PMU '%s' (CPUs %s) for event '%s'\n",
-                               cpu_list, pmu ? pmu->name : "cpu", buf, evsel__name(pos));
-               }
-               perf_cpu_map__put(intersect);
-               perf_cpu_map__put(online);
+               evsel__warn_user_requested_cpus(pos, user_requested_cpus);
        }
        perf_cpu_map__put(user_requested_cpus);
 }

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 3896a04d90af71f36bf3f6d1e357f83a1e5fdf83..d9b6bf78d67b07e2cecbc8045109ad908f2b1d97 100644 (file)
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -4091,3 +4091,27 @@ void evsel__uniquify_counter(struct evsel *counter)
                counter->uniquified_name = false;
        }
 }
+
+void evsel__warn_user_requested_cpus(struct evsel *evsel, struct perf_cpu_map *user_requested_cpus)
+{
+       struct perf_cpu_map *intersect, *online = NULL;
+       const struct perf_pmu *pmu = evsel__find_pmu(evsel);
+
+       if (pmu && pmu->is_core) {
+               intersect = perf_cpu_map__intersect(pmu->cpus, user_requested_cpus);
+       } else {
+               online = cpu_map__online();
+               intersect = perf_cpu_map__intersect(online, user_requested_cpus);
+       }
+       if (!perf_cpu_map__equal(intersect, user_requested_cpus)) {
+               char buf1[128];
+               char buf2[128];
+
+               cpu_map__snprint(user_requested_cpus, buf1, sizeof(buf1));
+               cpu_map__snprint(online ?: pmu->cpus, buf2, sizeof(buf2));
+               pr_warning("WARNING: A requested CPU in '%s' is not supported by PMU '%s' (CPUs %s) for event '%s'\n",
+                          buf1, pmu ? pmu->name : "cpu", buf2, evsel__name(evsel));
+       }
+       perf_cpu_map__put(intersect);
+       perf_cpu_map__put(online);
+}

diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index b84ee274602d7d2b62fc6e273edb4e2cb7782127..cefa8e64c0d5eba6128909dbab688fcbf74404ef 100644 (file)
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -574,4 +574,6 @@ void evsel__set_config_if_unset(struct perf_pmu *pmu, struct evsel *evsel,
 
 bool evsel__is_offcpu_event(struct evsel *evsel);
 
+void evsel__warn_user_requested_cpus(struct evsel *evsel, struct perf_cpu_map *user_requested_cpus);
+
 #endif /* __PERF_EVSEL_H */

diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index a59ae5ca0f894bfc014b4d2782fcdb51e6749dab..3fd6cc0c2794c67b0848b3a36e48b9499db10acd 100644 (file)
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -252,6 +252,7 @@ __add_event(struct list_head *list, int *idx,
        struct evsel *evsel;
        bool is_pmu_core;
        struct perf_cpu_map *cpus;
+       bool has_cpu_list = !perf_cpu_map__is_empty(cpu_list);
 
        /*
         * Ensure the first_wildcard_match's PMU matches that of the new event
@@ -276,7 +277,7 @@ __add_event(struct list_head *list, int *idx,
 
        if (pmu) {
                is_pmu_core = pmu->is_core;
-               cpus = perf_cpu_map__get(perf_cpu_map__is_empty(cpu_list) ? pmu->cpus : cpu_list);
+               cpus = perf_cpu_map__get(has_cpu_list ? cpu_list : pmu->cpus);
                perf_pmu__warn_invalid_formats(pmu);
                if (attr->type == PERF_TYPE_RAW || attr->type >= PERF_TYPE_MAX) {
                        perf_pmu__warn_invalid_config(pmu, attr->config, name,
@@ -291,10 +292,10 @@ __add_event(struct list_head *list, int *idx,
        } else {
                is_pmu_core = (attr->type == PERF_TYPE_HARDWARE ||
                               attr->type == PERF_TYPE_HW_CACHE);
-               if (perf_cpu_map__is_empty(cpu_list))
-                       cpus = is_pmu_core ? perf_cpu_map__new_online_cpus() : NULL;
-               else
+               if (has_cpu_list)
                        cpus = perf_cpu_map__get(cpu_list);
+               else
+                       cpus = is_pmu_core ? cpu_map__online() : NULL;
        }
        if (init_attr)
                event_attr_init(attr);
@@ -326,6 +327,9 @@ __add_event(struct list_head *list, int *idx,
        if (list)
                list_add_tail(&evsel->core.node, list);
 
+       if (has_cpu_list)
+               evsel__warn_user_requested_cpus(evsel, cpu_list);
+
        return evsel;
 }