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-rw-r--r--tools/perf/util/evsel.c28
1 files changed, 28 insertions, 0 deletions
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index ee6ee3f45c2a..0c88e5c12dab 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -1378,3 +1378,31 @@ int perf_evsel__fprintf(struct perf_evsel *evsel,
fputc('\n', fp);
return ++printed;
}
+
+bool perf_evsel__fallback(struct perf_evsel *evsel, int err,
+ char *msg, size_t msgsize)
+{
+ if ((err == ENOENT || err == ENXIO) &&
+ evsel->attr.type == PERF_TYPE_HARDWARE &&
+ evsel->attr.config == PERF_COUNT_HW_CPU_CYCLES) {
+ /*
+ * If it's cycles then fall back to hrtimer based
+ * cpu-clock-tick sw counter, which is always available even if
+ * no PMU support.
+ *
+ * PPC returns ENXIO until 2.6.37 (behavior changed with commit
+ * b0a873e).
+ */
+ scnprintf(msg, msgsize, "%s",
+"The cycles event is not supported, trying to fall back to cpu-clock-ticks");
+
+ evsel->attr.type = PERF_TYPE_SOFTWARE;
+ evsel->attr.config = PERF_COUNT_SW_CPU_CLOCK;
+
+ free(evsel->name);
+ evsel->name = NULL;
+ return true;
+ }
+
+ return false;
+}