perf pmus: Create placholder regardless of scanning core_only

If scanning all PMUs the placeholder is still necessary if no core PMU
is found. This situation occurs in perf test's parse-events test,
when uncore events appear before core.

Fixes: 628eaa4e877af823 ("perf pmus: Add placeholder core PMU")
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Thomas Richter <tmricht@linux.ibm.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230706183705.601412-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/pmus.c b/tools/perf/util/pmus.c
index 3cd9de4..c58ba9f 100644 (file)
--- a/tools/perf/util/pmus.c
+++ b/tools/perf/util/pmus.c
@@ -152,16 +152,14 @@ static void pmu_read_sysfs(bool core_only)
        }
 
        closedir(dir);
-       if (core_only) {
-               if (!list_empty(&core_pmus))
-                       read_sysfs_core_pmus = true;
-               else {
-                       if (perf_pmu__create_placeholder_core_pmu(&core_pmus))
-                               read_sysfs_core_pmus = true;
-               }
-       } else {
+       if (list_empty(&core_pmus)) {
+               if (!perf_pmu__create_placeholder_core_pmu(&core_pmus))
+                       pr_err("Failure to set up any core PMUs\n");
+       }
+       if (!list_empty(&core_pmus)) {
                read_sysfs_core_pmus = true;
-               read_sysfs_all_pmus = true;
+               if (!core_only)
+                       read_sysfs_all_pmus = true;
        }
 }