perf evsel: Add verbose output for sys_perf_event_open fallback

Adding info about what is being switched off in the sys_perf_event_open
fallback.

New output (notice the 'switching off' lines):

  $ perf stat -e '{cycles,instructions}' -vvv ls
  Using CPUID GenuineIntel-6-3D
  intel_pt default config: tsc
  ------------------------------------------------------------
  perf_event_attr:
    size                             112
    sample_type                      IDENTIFIER
    read_format                      TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING|ID|GROUP
    disabled                         1
    inherit                          1
    enable_on_exec                   1
    exclude_guest                    1
  ------------------------------------------------------------
  sys_perf_event_open: pid 3591  cpu -1  group_fd -1  flags 0x8
  sys_perf_event_open failed, error -22
  switching off cloexec flag
  ------------------------------------------------------------
  perf_event_attr:
    size                             112
    sample_type                      IDENTIFIER
    read_format                      TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING|ID|GROUP
    disabled                         1
    inherit                          1
    enable_on_exec                   1
    exclude_guest                    1
  ------------------------------------------------------------
  sys_perf_event_open: pid 3591  cpu -1  group_fd -1  flags 0
  sys_perf_event_open failed, error -22
  switching off exclude_guest, exclude_host
  ------------------------------------------------------------
  perf_event_attr:
    size                             112
    sample_type                      IDENTIFIER
    read_format                      TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING|ID|GROUP
    disabled                         1
    inherit                          1
    enable_on_exec                   1
  ------------------------------------------------------------
  sys_perf_event_open: pid 3591  cpu -1  group_fd -1  flags 0
  sys_perf_event_open failed, error -22
  switching off sample_id_all
  ------------------------------------------------------------
  perf_event_attr:
    size                             112
    sample_type                      IDENTIFIER
    read_format                      TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING|ID|GROUP
    disabled                         1
    inherit                          1
    enable_on_exec                   1
  ...

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20170721121212.21414-2-jolsa@kernel.org
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 6dd069a41ac3088f55a649b7080d850a2c757f18..450b5fadf8cb07937f3e424b6f3ee35177c08632 100644 (file)
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -1671,31 +1671,39 @@ try_fallback:
         */
        if (!perf_missing_features.write_backward && evsel->attr.write_backward) {
                perf_missing_features.write_backward = true;
+               pr_debug2("switching off write_backward\n");
                goto out_close;
        } else if (!perf_missing_features.clockid_wrong && evsel->attr.use_clockid) {
                perf_missing_features.clockid_wrong = true;
+               pr_debug2("switching off clockid\n");
                goto fallback_missing_features;
        } else if (!perf_missing_features.clockid && evsel->attr.use_clockid) {
                perf_missing_features.clockid = true;
+               pr_debug2("switching off use_clockid\n");
                goto fallback_missing_features;
        } else if (!perf_missing_features.cloexec && (flags & PERF_FLAG_FD_CLOEXEC)) {
                perf_missing_features.cloexec = true;
+               pr_debug2("switching off cloexec flag\n");
                goto fallback_missing_features;
        } else if (!perf_missing_features.mmap2 && evsel->attr.mmap2) {
                perf_missing_features.mmap2 = true;
+               pr_debug2("switching off mmap2\n");
                goto fallback_missing_features;
        } else if (!perf_missing_features.exclude_guest &&
                   (evsel->attr.exclude_guest || evsel->attr.exclude_host)) {
                perf_missing_features.exclude_guest = true;
+               pr_debug2("switching off exclude_guest, exclude_host\n");
                goto fallback_missing_features;
        } else if (!perf_missing_features.sample_id_all) {
                perf_missing_features.sample_id_all = true;
+               pr_debug2("switching off sample_id_all\n");
                goto retry_sample_id;
        } else if (!perf_missing_features.lbr_flags &&
                        (evsel->attr.branch_sample_type &
                         (PERF_SAMPLE_BRANCH_NO_CYCLES |
                          PERF_SAMPLE_BRANCH_NO_FLAGS))) {
                perf_missing_features.lbr_flags = true;
+               pr_debug2("switching off branch sample type no (cycles/flags)\n");
                goto fallback_missing_features;
        }
 out_close: