1 files changed, 46 insertions, 139 deletions

diff --git a/tools/perf/util/record.c b/tools/perf/util/record.c
index 7def66168503..a4cc11592f6b 100644
--- a/tools/perf/util/record.c
+++ b/tools/perf/util/record.c
@@ -10,161 +10,64 @@
 #include <subcmd/parse-options.h>
 #include <perf/cpumap.h>
 #include "cloexec.h"
+#include "util/perf_api_probe.h"
 #include "record.h"
 #include "../perf-sys.h"
 
-typedef void (*setup_probe_fn_t)(struct evsel *evsel);
-
-static int perf_do_probe_api(setup_probe_fn_t fn, int cpu, const char *str)
+/*
+ * evsel__config_leader_sampling() uses special rules for leader sampling.
+ * However, if the leader is an AUX area event, then assume the event to sample
+ * is the next event.
+ */
+static struct evsel *evsel__read_sampler(struct evsel *evsel, struct evlist *evlist)
 {
-	struct evlist *evlist;
-	struct evsel *evsel;
-	unsigned long flags = perf_event_open_cloexec_flag();
-	int err = -EAGAIN, fd;
-	static pid_t pid = -1;
-
-	evlist = evlist__new();
-	if (!evlist)
-		return -ENOMEM;
-
-	if (parse_events(evlist, str, NULL))
-		goto out_delete;
-
-	evsel = evlist__first(evlist);
+	struct evsel *leader = evsel->leader;
 
-	while (1) {
-		fd = sys_perf_event_open(&evsel->core.attr, pid, cpu, -1, flags);
-		if (fd < 0) {
-			if (pid == -1 && errno == EACCES) {
-				pid = 0;
-				continue;
-			}
-			goto out_delete;
+	if (evsel__is_aux_event(leader)) {
+		evlist__for_each_entry(evlist, evsel) {
+			if (evsel->leader == leader && evsel != evsel->leader)
+				return evsel;
 		}
-		break;
-	}
-	close(fd);
-
-	fn(evsel);
-
-	fd = sys_perf_event_open(&evsel->core.attr, pid, cpu, -1, flags);
-	if (fd < 0) {
-		if (errno == EINVAL)
-			err = -EINVAL;
-		goto out_delete;
 	}
-	close(fd);
-	err = 0;
-
-out_delete:
-	evlist__delete(evlist);
-	return err;
-}
-
-static bool perf_probe_api(setup_probe_fn_t fn)
-{
-	const char *try[] = {"cycles:u", "instructions:u", "cpu-clock:u", NULL};
-	struct perf_cpu_map *cpus;
-	int cpu, ret, i = 0;
-
-	cpus = perf_cpu_map__new(NULL);
-	if (!cpus)
-		return false;
-	cpu = cpus->map[0];
-	perf_cpu_map__put(cpus);
-
-	do {
-		ret = perf_do_probe_api(fn, cpu, try[i++]);
-		if (!ret)
-			return true;
-	} while (ret == -EAGAIN && try[i]);
 
-	return false;
+	return leader;
 }
 
-static void perf_probe_sample_identifier(struct evsel *evsel)
+static void evsel__config_leader_sampling(struct evsel *evsel, struct evlist *evlist)
 {
-	evsel->core.attr.sample_type |= PERF_SAMPLE_IDENTIFIER;
-}
-
-static void perf_probe_comm_exec(struct evsel *evsel)
-{
-	evsel->core.attr.comm_exec = 1;
-}
-
-static void perf_probe_context_switch(struct evsel *evsel)
-{
-	evsel->core.attr.context_switch = 1;
-}
-
-bool perf_can_sample_identifier(void)
-{
-	return perf_probe_api(perf_probe_sample_identifier);
-}
+	struct perf_event_attr *attr = &evsel->core.attr;
+	struct evsel *leader = evsel->leader;
+	struct evsel *read_sampler;
 
-static bool perf_can_comm_exec(void)
-{
-	return perf_probe_api(perf_probe_comm_exec);
-}
+	if (!leader->sample_read)
+		return;
 
-bool perf_can_record_switch_events(void)
-{
-	return perf_probe_api(perf_probe_context_switch);
-}
+	read_sampler = evsel__read_sampler(evsel, evlist);
 
-bool perf_can_record_cpu_wide(void)
-{
-	struct perf_event_attr attr = {
-		.type = PERF_TYPE_SOFTWARE,
-		.config = PERF_COUNT_SW_CPU_CLOCK,
-		.exclude_kernel = 1,
-	};
-	struct perf_cpu_map *cpus;
-	int cpu, fd;
-
-	cpus = perf_cpu_map__new(NULL);
-	if (!cpus)
-		return false;
-	cpu = cpus->map[0];
-	perf_cpu_map__put(cpus);
+	if (evsel == read_sampler)
+		return;
 
-	fd = sys_perf_event_open(&attr, -1, cpu, -1, 0);
-	if (fd < 0)
-		return false;
-	close(fd);
-
-	return true;
-}
-
-/*
- * Architectures are expected to know if AUX area sampling is supported by the
- * hardware. Here we check for kernel support.
- */
-bool perf_can_aux_sample(void)
-{
-	struct perf_event_attr attr = {
-		.size = sizeof(struct perf_event_attr),
-		.exclude_kernel = 1,
-		/*
-		 * Non-zero value causes the kernel to calculate the effective
-		 * attribute size up to that byte.
-		 */
-		.aux_sample_size = 1,
-	};
-	int fd;
-
-	fd = sys_perf_event_open(&attr, -1, 0, -1, 0);
 	/*
-	 * If the kernel attribute is big enough to contain aux_sample_size
-	 * then we assume that it is supported. We are relying on the kernel to
-	 * validate the attribute size before anything else that could be wrong.
+	 * Disable sampling for all group members other than the leader in
+	 * case the leader 'leads' the sampling, except when the leader is an
+	 * AUX area event, in which case the 2nd event in the group is the one
+	 * that 'leads' the sampling.
 	 */
-	if (fd < 0 && errno == E2BIG)
-		return false;
-	if (fd >= 0)
-		close(fd);
+	attr->freq           = 0;
+	attr->sample_freq    = 0;
+	attr->sample_period  = 0;
+	attr->write_backward = 0;
 
-	return true;
+	/*
+	 * We don't get a sample for slave events, we make them when delivering
+	 * the group leader sample. Set the slave event to follow the master
+	 * sample_type to ease up reporting.
+	 * An AUX area event also has sample_type requirements, so also include
+	 * the sample type bits from the leader's sample_type to cover that
+	 * case.
+	 */
+	attr->sample_type = read_sampler->core.attr.sample_type |
+			    leader->core.attr.sample_type;
 }
 
 void perf_evlist__config(struct evlist *evlist, struct record_opts *opts,
@@ -188,11 +91,15 @@ void perf_evlist__config(struct evlist *evlist, struct record_opts *opts,
 	use_comm_exec = perf_can_comm_exec();
 
 	evlist__for_each_entry(evlist, evsel) {
-		perf_evsel__config(evsel, opts, callchain);
+		evsel__config(evsel, opts, callchain);
 		if (evsel->tracking && use_comm_exec)
 			evsel->core.attr.comm_exec = 1;
 	}
 
+	/* Configure leader sampling here now that the sample type is known */
+	evlist__for_each_entry(evlist, evsel)
+		evsel__config_leader_sampling(evsel, evlist);
+
 	if (opts->full_auxtrace) {
 		/*
 		 * Need to be able to synthesize and parse selected events with
@@ -215,7 +122,7 @@ void perf_evlist__config(struct evlist *evlist, struct record_opts *opts,
 
 	if (sample_id) {
 		evlist__for_each_entry(evlist, evsel)
-			perf_evsel__set_sample_id(evsel, use_sample_identifier);
+			evsel__set_sample_id(evsel, use_sample_identifier);
 	}
 
 	perf_evlist__set_id_pos(evlist);