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

[tip-bot for Kim Phillips]

Commit-ID:  114bc191c37028d87a540251d93e7b328f4de3fe
Gitweb:     https://git.kernel.org/tip/114bc191c37028d87a540251d93e7b328f4de3fe
Author:     Kim Phillips <kim.phillips@xxxxxxx>
AuthorDate: Tue, 14 Nov 2017 15:04:52 -0600
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Thu, 16 Nov 2017 14:50:03 -0300

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@xxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20171114150452.e846f2e23684c7d7d8ee706f@xxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/util/evsel.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index cb9bcdb..b8e9def 100644
--- 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.");