perf evsel: Say which PMU Hardware event doesn't support sampling/overflow-interrupts

Help identify to the user the event with the unsupported sampling error.
Also suggest a corrective action.

BEFORE:

$ sudo ./oldperf record -e armv8_pmuv3/mem_access/,ccn/cycles/,armv8_pmuv3/l2d_cache/ true
Error:
PMU Hardware doesn't support sampling/overflow-interrupts.

AFTER:

$ sudo ./newperf record -e armv8_pmuv3/mem_access/,ccn/cycles/,armv8_pmuv3/l2d_cache/ true
Error:
ccn/cycles/: PMU Hardware doesn't support sampling/overflow-interrupts. Try 'perf stat'

Signed-off-by: Kim Phillips <kim.phillips@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20171114150452.e846f2e23684c7d7d8ee706f@arm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index cb9bcdb..b8e9def 100644 (file)
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -2745,8 +2745,9 @@ int perf_evsel__open_strerror(struct perf_evsel *evsel, struct target *target,
                break;
        case EOPNOTSUPP:
                if (evsel->attr.sample_period != 0)
-                       return scnprintf(msg, size, "%s",
-       "PMU Hardware doesn't support sampling/overflow-interrupts.");
+                       return scnprintf(msg, size,
+       "%s: PMU Hardware doesn't support sampling/overflow-interrupts. Try 'perf stat'",
+                                        perf_evsel__name(evsel));
                if (evsel->attr.precise_ip)
                        return scnprintf(msg, size, "%s",
        "\'precise\' request may not be supported. Try removing 'p' modifier.");