[PATCH 2/2] perf tool: evsel: say which PMU Hardware event doesn't support sampling/overflow-interrupts

From: Kim Phillips
Date: Fri Oct 27 2017 - 18:20:42 EST


Help identify to the user the event with the unsupported sampling
error. Also provide an alternative 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>
---
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 f894893c203d..a0f298726324 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -2739,8 +2739,9 @@ 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.");
--
2.14.2