libperf: Add perf_evsel tests

Add 2 simple perf_evsel tests to test counters reading interface through
the struct evsel object.

Committer testing:

  # make -C tools/perf/lib tests
  make: Entering directory '/home/acme/git/perf/tools/perf/lib'
    LINK     test-cpumap-a
    LINK     test-threadmap-a
    LINK     test-evlist-a
    LINK     test-evsel-a
    LINK     test-cpumap-so
    LINK     test-threadmap-so
    LINK     test-evlist-so
    LINK     test-evsel-so
  running static:
  - running test-cpumap.c...OK
  - running test-threadmap.c...OK
  - running test-evlist.c...OK
  - running test-evsel.c...OK
  running dynamic:
  - running test-cpumap.c...OK
  - running test-threadmap.c...OK
  - running test-evlist.c...OK
  - running test-evsel.c...OK
  make: Leaving directory '/home/acme/git/perf/tools/perf/lib'
  #
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20190721112506.12306-77-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/lib/tests/Makefile

 # SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
 
-TESTS = test-cpumap test-threadmap test-evlist
+TESTS = test-cpumap test-threadmap test-evlist test-evsel
 
 TESTS_SO := $(addsuffix -so,$(TESTS))
 TESTS_A  := $(addsuffix -a,$(TESTS))

tools/perf/lib/tests/test-evsel.c

+// SPDX-License-Identifier: GPL-2.0
+#include <linux/perf_event.h>
+#include <perf/cpumap.h>
+#include <perf/threadmap.h>
+#include <perf/evsel.h>
+#include <internal/tests.h>
+
+static int test_stat_cpu(void)
+{
+	struct perf_cpu_map *cpus;
+	struct perf_evsel *evsel;
+	struct perf_event_attr attr = {
+		.type	= PERF_TYPE_SOFTWARE,
+		.config	= PERF_COUNT_SW_CPU_CLOCK,
+	};
+	int err, cpu, tmp;
+
+	cpus = perf_cpu_map__new(NULL);
+	__T("failed to create cpus", cpus);
+
+	evsel = perf_evsel__new(&attr);
+	__T("failed to create evsel", evsel);
+
+	err = perf_evsel__open(evsel, cpus, NULL);
+	__T("failed to open evsel", err == 0);
+
+	perf_cpu_map__for_each_cpu(cpu, tmp, cpus) {
+		struct perf_counts_values counts = { .val = 0 };
+
+		perf_evsel__read(evsel, cpu, 0, &counts);
+		__T("failed to read value for evsel", counts.val != 0);
+	}
+
+	perf_evsel__close(evsel);
+	perf_evsel__delete(evsel);
+
+	perf_cpu_map__put(cpus);
+	return 0;
+}
+
+static int test_stat_thread(void)
+{
+	struct perf_counts_values counts = { .val = 0 };
+	struct perf_thread_map *threads;
+	struct perf_evsel *evsel;
+	struct perf_event_attr attr = {
+		.type	= PERF_TYPE_SOFTWARE,
+		.config	= PERF_COUNT_SW_TASK_CLOCK,
+	};
+	int err;
+
+	threads = perf_thread_map__new_dummy();
+	__T("failed to create threads", threads);
+
+	perf_thread_map__set_pid(threads, 0, 0);
+
+	evsel = perf_evsel__new(&attr);
+	__T("failed to create evsel", evsel);
+
+	err = perf_evsel__open(evsel, NULL, threads);
+	__T("failed to open evsel", err == 0);
+
+	perf_evsel__read(evsel, 0, 0, &counts);
+	__T("failed to read value for evsel", counts.val != 0);
+
+	perf_evsel__close(evsel);
+	perf_evsel__delete(evsel);
+
+	perf_thread_map__put(threads);
+	return 0;
+}
+
+int main(int argc, char **argv)
+{
+	__T_START;
+
+	test_stat_cpu();
+	test_stat_thread();
+
+	__T_OK;
+	return 0;
+}