perf evsel: Emit warning about kernel not supporting the data page size sample_type bit

Before we had this unhelpful message:

  $ perf record --data-page-size sleep 1
  Error:
  The sys_perf_event_open() syscall returned with 22 (Invalid argument) for event (cycles:u).
  /bin/dmesg | grep -i perf may provide additional information.
  $

Add support to the perf_missing_features variable to remember what
caused evsel__open() to fail and then use that information in
evsel__open_strerror().

  $ perf record --data-page-size sleep 1
  Error:
  Asking for the data page size isn't supported by this kernel.
  $

Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Stephane Eranian <eranian@google.com>
Cc: Will Deacon <will@kernel.org>
Link: http://lore.kernel.org/lkml/20201207170759.GB129853@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 5e6085c..c26ea82 100644 (file)
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -1873,7 +1873,12 @@ try_fallback:
         * Must probe features in the order they were added to the
         * perf_event_attr interface.
         */
-        if (!perf_missing_features.cgroup && evsel->core.attr.cgroup) {
+        if (!perf_missing_features.data_page_size &&
+           (evsel->core.attr.sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)) {
+               perf_missing_features.data_page_size = true;
+               pr_debug2_peo("Kernel has no PERF_SAMPLE_DATA_PAGE_SIZE support, bailing out\n");
+               goto out_close;
+       } else if (!perf_missing_features.cgroup && evsel->core.attr.cgroup) {
                perf_missing_features.cgroup = true;
                pr_debug2_peo("Kernel has no cgroup sampling support, bailing out\n");
                goto out_close;
@@ -2673,6 +2678,8 @@ int evsel__open_strerror(struct evsel *evsel, struct target *target,
        "We found oprofile daemon running, please stop it and try again.");
                break;
        case EINVAL:
+               if (evsel->core.attr.sample_type & PERF_SAMPLE_DATA_PAGE_SIZE && perf_missing_features.data_page_size)
+                       return scnprintf(msg, size, "Asking for the data page size isn't supported by this kernel.");
                if (evsel->core.attr.write_backward && perf_missing_features.write_backward)
                        return scnprintf(msg, size, "Reading from overwrite event is not supported by this kernel.");
                if (perf_missing_features.clockid)

diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index 79a860d..cd1d8dd 100644 (file)
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -144,6 +144,7 @@ struct perf_missing_features {
        bool aux_output;
        bool branch_hw_idx;
        bool cgroup;
+       bool data_page_size;
 };
 
 extern struct perf_missing_features perf_missing_features;