scftorture: Count single_rpc offline failures in statistics outputgrafted

scf_torture_stats_print() aggregates each invoker thread's counters
into a local scf_statistics structure before printing, but the
n_single_rpc_ofl field is missing from the aggregation loop.  As a
result, the "single_rpc_ofl" value printed in the statistics line is
always zero, even when smp_call_function_single() invocations for the
RPC test have failed due to offline CPUs and been counted by the
invoker threads.

Add the missing accumulation so that the printed value reflects the
actual counts.

Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

1 files changed, 164 insertions, 0 deletions

diff --git a/tools/perf/tests/keep-tracking.c b/tools/perf/tests/keep-tracking.c
new file mode 100644
index 000000000..729cc9cc1
--- /dev/null
+++ b/tools/perf/tests/keep-tracking.c
@@ -0,0 +1,164 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/types.h>
+#include <limits.h>
+#include <unistd.h>
+#include <sys/prctl.h>
+#include <perf/cpumap.h>
+#include <perf/evlist.h>
+#include <perf/mmap.h>
+
+#include "debug.h"
+#include "parse-events.h"
+#include "evlist.h"
+#include "evsel.h"
+#include "record.h"
+#include "thread_map.h"
+#include "tests.h"
+#include "util/mmap.h"
+
+#define CHECK__(x) {				\
+	while ((x) < 0) {			\
+		pr_debug(#x " failed!\n");	\
+		goto out_err;			\
+	}					\
+}
+
+#define CHECK_NOT_NULL__(x) {			\
+	while ((x) == NULL) {			\
+		pr_debug(#x " failed!\n");	\
+		goto out_err;			\
+	}					\
+}
+
+static int find_comm(struct evlist *evlist, const char *comm)
+{
+	union perf_event *event;
+	struct mmap *md;
+	int i, found;
+
+	found = 0;
+	for (i = 0; i < evlist->core.nr_mmaps; i++) {
+		md = &evlist->mmap[i];
+		if (perf_mmap__read_init(&md->core) < 0)
+			continue;
+		while ((event = perf_mmap__read_event(&md->core)) != NULL) {
+			if (event->header.type == PERF_RECORD_COMM &&
+			    (pid_t)event->comm.pid == getpid() &&
+			    (pid_t)event->comm.tid == getpid() &&
+			    strcmp(event->comm.comm, comm) == 0)
+				found += 1;
+			perf_mmap__consume(&md->core);
+		}
+		perf_mmap__read_done(&md->core);
+	}
+	return found;
+}
+
+/**
+ * test__keep_tracking - test using a dummy software event to keep tracking.
+ *
+ * This function implements a test that checks that tracking events continue
+ * when an event is disabled but a dummy software event is not disabled.  If the
+ * test passes %0 is returned, otherwise %-1 is returned.
+ */
+static int test__keep_tracking(struct test_suite *test __maybe_unused, int subtest __maybe_unused)
+{
+	struct record_opts opts = {
+		.mmap_pages	     = UINT_MAX,
+		.user_freq	     = UINT_MAX,
+		.user_interval	     = ULLONG_MAX,
+		.target		     = {
+			.uses_mmap   = true,
+		},
+	};
+	struct perf_thread_map *threads = NULL;
+	struct perf_cpu_map *cpus = NULL;
+	struct evlist *evlist = NULL;
+	struct evsel *evsel = NULL;
+	int found, err = -1;
+	const char *comm;
+
+	threads = thread_map__new_by_tid(getpid());
+	CHECK_NOT_NULL__(threads);
+
+	cpus = perf_cpu_map__new_online_cpus();
+	CHECK_NOT_NULL__(cpus);
+
+	evlist = evlist__new();
+	CHECK_NOT_NULL__(evlist);
+
+	perf_evlist__set_maps(&evlist->core, cpus, threads);
+
+	CHECK__(parse_event(evlist, "dummy:u"));
+	CHECK__(parse_event(evlist, "cpu-cycles:u"));
+
+	evlist__config(evlist, &opts, NULL);
+
+	evsel = evlist__first(evlist);
+
+	evsel->core.attr.comm = 1;
+	evsel->core.attr.disabled = 1;
+	evsel->core.attr.enable_on_exec = 0;
+
+	if (evlist__open(evlist) < 0) {
+		pr_debug("Unable to open dummy and cycles event\n");
+		err = TEST_SKIP;
+		goto out_err;
+	}
+
+	CHECK__(evlist__mmap(evlist, UINT_MAX));
+
+	/*
+	 * First, test that a 'comm' event can be found when the event is
+	 * enabled.
+	 */
+
+	evlist__enable(evlist);
+
+	comm = "Test COMM 1";
+	CHECK__(prctl(PR_SET_NAME, (unsigned long)comm, 0, 0, 0));
+
+	evlist__disable(evlist);
+
+	found = find_comm(evlist, comm);
+	if (found != 1) {
+		pr_debug("First time, failed to find tracking event.\n");
+		goto out_err;
+	}
+
+	/*
+	 * Secondly, test that a 'comm' event can be found when the event is
+	 * disabled with the dummy event still enabled.
+	 */
+
+	evlist__enable(evlist);
+
+	evsel = evlist__last(evlist);
+
+	CHECK__(evsel__disable(evsel));
+
+	comm = "Test COMM 2";
+	CHECK__(prctl(PR_SET_NAME, (unsigned long)comm, 0, 0, 0));
+
+	evlist__disable(evlist);
+
+	found = find_comm(evlist, comm);
+	if (found != 1) {
+		pr_debug("Second time, failed to find tracking event.\n");
+		goto out_err;
+	}
+
+	err = 0;
+
+out_err:
+	if (evlist) {
+		evlist__disable(evlist);
+		evlist__delete(evlist);
+	}
+	perf_cpu_map__put(cpus);
+	perf_thread_map__put(threads);
+
+	return err;
+}
+
+DEFINE_SUITE("Use a dummy software event to keep tracking", keep_tracking);