tools/perf: Handle -EOPNOTSUPP for sampling events

This allows (with a previous change to the perf error return ABI) for
calling out in userspace the exact reason for perf record failing
when PMU doesn't support overflow interrupts.

Note that this needs to be put ahead of existing precise_ip check as
that gets hit otherwise for the sampling fail case as well.

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <acme@redhat.com>
Cc: <linux-snps-arc@lists.infradead.org>
Cc: <vincent.weaver@maine.edu>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Vineet Gupta <Vineet.Gupta1@synopsys.com>
Link: http://lkml.kernel.org/r/1462786660-2900-2-git-send-email-vgupta@synopsys.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 245ac503f2111f5e7f651322f500063e11804897..8d30cbda51b639913bd9db963b9b25eb5c02f80d 100644 (file)
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -2384,6 +2384,9 @@ int perf_evsel__open_strerror(struct perf_evsel *evsel, struct target *target,
         "No such device - did you specify an out-of-range profile CPU?");
                break;
        case EOPNOTSUPP:
+               if (evsel->attr.sample_period != 0)
+                       return scnprintf(msg, size, "%s",
+       "PMU Hardware doesn't support sampling/overflow-interrupts.");
                if (evsel->attr.precise_ip)
                        return scnprintf(msg, size, "%s",
        "\'precise\' request may not be supported. Try removing 'p' modifier.");