Commit 456ef4c1 authored by Arnaldo Carvalho de Melo's avatar Arnaldo Carvalho de Melo
Browse files

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: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 542b88fd

tools/perf/util/evsel.c

+8 −1
Original line number Diff line number Diff line
@@ -1873,7 +1873,12 @@ static int evsel__open_cpu(struct evsel *evsel, struct perf_cpu_map *cpus, 
	 * 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)

tools/perf/util/evsel.h

+1 −0
Original line number Diff line number Diff line
@@ -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;