1 files changed, 326 insertions, 0 deletions
diff --git a/tools/perf/util/record.c b/tools/perf/util/record.c
new file mode 100644
index 000000000..9cfc7bf16
--- /dev/null
+++ b/tools/perf/util/record.c
@@ -0,0 +1,326 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "evlist.h"
+#include "evsel.h"
+#include "cpumap.h"
+#include "parse-events.h"
+#include <errno.h>
+#include <api/fs/fs.h>
+#include <subcmd/parse-options.h>
+#include "util.h"
+#include "cloexec.h"
+
+typedef void (*setup_probe_fn_t)(struct perf_evsel *evsel);
+
+static int perf_do_probe_api(setup_probe_fn_t fn, int cpu, const char *str)
+{
+	struct perf_evlist *evlist;
+	struct perf_evsel *evsel;
+	unsigned long flags = perf_event_open_cloexec_flag();
+	int err = -EAGAIN, fd;
+	static pid_t pid = -1;
+
+	evlist = perf_evlist__new();
+	if (!evlist)
+		return -ENOMEM;
+
+	if (parse_events(evlist, str, NULL))
+		goto out_delete;
+
+	evsel = perf_evlist__first(evlist);
+
+	while (1) {
+		fd = sys_perf_event_open(&evsel->attr, pid, cpu, -1, flags);
+		if (fd < 0) {
+			if (pid == -1 && errno == EACCES) {
+				pid = 0;
+				continue;
+			}
+			goto out_delete;
+		}
+		break;
+	}
+	close(fd);
+
+	fn(evsel);
+
+	fd = sys_perf_event_open(&evsel->attr, pid, cpu, -1, flags);
+	if (fd < 0) {
+		if (errno == EINVAL)
+			err = -EINVAL;
+		goto out_delete;
+	}
+	close(fd);
+	err = 0;
+
+out_delete:
+	perf_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 cpu_map *cpus;
+	int cpu, ret, i = 0;
+
+	cpus = cpu_map__new(NULL);
+	if (!cpus)
+		return false;
+	cpu = cpus->map[0];
+	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;
+}
+
+static void perf_probe_sample_identifier(struct perf_evsel *evsel)
+{
+	evsel->attr.sample_type |= PERF_SAMPLE_IDENTIFIER;
+}
+
+static void perf_probe_comm_exec(struct perf_evsel *evsel)
+{
+	evsel->attr.comm_exec = 1;
+}
+
+static void perf_probe_context_switch(struct perf_evsel *evsel)
+{
+	evsel->attr.context_switch = 1;
+}
+
+bool perf_can_sample_identifier(void)
+{
+	return perf_probe_api(perf_probe_sample_identifier);
+}
+
+static bool perf_can_comm_exec(void)
+{
+	return perf_probe_api(perf_probe_comm_exec);
+}
+
+bool perf_can_record_switch_events(void)
+{
+	return perf_probe_api(perf_probe_context_switch);
+}
+
+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 cpu_map *cpus;
+	int cpu, fd;
+
+	cpus = cpu_map__new(NULL);
+	if (!cpus)
+		return false;
+	cpu = cpus->map[0];
+	cpu_map__put(cpus);
+
+	fd = sys_perf_event_open(&attr, -1, cpu, -1, 0);
+	if (fd < 0)
+		return false;
+	close(fd);
+
+	return true;
+}
+
+void perf_evlist__config(struct perf_evlist *evlist, struct record_opts *opts,
+			 struct callchain_param *callchain)
+{
+	struct perf_evsel *evsel;
+	bool use_sample_identifier = false;
+	bool use_comm_exec;
+	bool sample_id = opts->sample_id;
+
+	/*
+	 * Set the evsel leader links before we configure attributes,
+	 * since some might depend on this info.
+	 */
+	if (opts->group)
+		perf_evlist__set_leader(evlist);
+
+	if (evlist->cpus->map[0] < 0)
+		opts->no_inherit = true;
+
+	use_comm_exec = perf_can_comm_exec();
+
+	evlist__for_each_entry(evlist, evsel) {
+		perf_evsel__config(evsel, opts, callchain);
+		if (evsel->tracking && use_comm_exec)
+			evsel->attr.comm_exec = 1;
+	}
+
+	if (opts->full_auxtrace) {
+		/*
+		 * Need to be able to synthesize and parse selected events with
+		 * arbitrary sample types, which requires always being able to
+		 * match the id.
+		 */
+		use_sample_identifier = perf_can_sample_identifier();
+		sample_id = true;
+	} else if (evlist->nr_entries > 1) {
+		struct perf_evsel *first = perf_evlist__first(evlist);
+
+		evlist__for_each_entry(evlist, evsel) {
+			if (evsel->attr.sample_type == first->attr.sample_type)
+				continue;
+			use_sample_identifier = perf_can_sample_identifier();
+			break;
+		}
+		sample_id = true;
+	}
+
+	if (sample_id) {
+		evlist__for_each_entry(evlist, evsel)
+			perf_evsel__set_sample_id(evsel, use_sample_identifier);
+	}
+
+	perf_evlist__set_id_pos(evlist);
+}
+
+static int get_max_rate(unsigned int *rate)
+{
+	return sysctl__read_int("kernel/perf_event_max_sample_rate", (int *)rate);
+}
+
+static int record_opts__config_freq(struct record_opts *opts)
+{
+	bool user_freq = opts->user_freq != UINT_MAX;
+	unsigned int max_rate;
+
+	if (opts->user_interval != ULLONG_MAX)
+		opts->default_interval = opts->user_interval;
+	if (user_freq)
+		opts->freq = opts->user_freq;
+
+	/*
+	 * User specified count overrides default frequency.
+	 */
+	if (opts->default_interval)
+		opts->freq = 0;
+	else if (opts->freq) {
+		opts->default_interval = opts->freq;
+	} else {
+		pr_err("frequency and count are zero, aborting\n");
+		return -1;
+	}
+
+	if (get_max_rate(&max_rate))
+		return 0;
+
+	/*
+	 * User specified frequency is over current maximum.
+	 */
+	if (user_freq && (max_rate < opts->freq)) {
+		if (opts->strict_freq) {
+			pr_err("error: Maximum frequency rate (%'u Hz) exceeded.\n"
+			       "       Please use -F freq option with a lower value or consider\n"
+			       "       tweaking /proc/sys/kernel/perf_event_max_sample_rate.\n",
+			       max_rate);
+			return -1;
+		} else {
+			pr_warning("warning: Maximum frequency rate (%'u Hz) exceeded, throttling from %'u Hz to %'u Hz.\n"
+				   "         The limit can be raised via /proc/sys/kernel/perf_event_max_sample_rate.\n"
+				   "         The kernel will lower it when perf's interrupts take too long.\n"
+				   "         Use --strict-freq to disable this throttling, refusing to record.\n",
+				   max_rate, opts->freq, max_rate);
+
+			opts->freq = max_rate;
+		}
+	}
+
+	/*
+	 * Default frequency is over current maximum.
+	 */
+	if (max_rate < opts->freq) {
+		pr_warning("Lowering default frequency rate to %u.\n"
+			   "Please consider tweaking "
+			   "/proc/sys/kernel/perf_event_max_sample_rate.\n",
+			   max_rate);
+		opts->freq = max_rate;
+	}
+
+	return 0;
+}
+
+int record_opts__config(struct record_opts *opts)
+{
+	return record_opts__config_freq(opts);
+}
+
+bool perf_evlist__can_select_event(struct perf_evlist *evlist, const char *str)
+{
+	struct perf_evlist *temp_evlist;
+	struct perf_evsel *evsel;
+	int err, fd, cpu;
+	bool ret = false;
+	pid_t pid = -1;
+
+	temp_evlist = perf_evlist__new();
+	if (!temp_evlist)
+		return false;
+
+	err = parse_events(temp_evlist, str, NULL);
+	if (err)
+		goto out_delete;
+
+	evsel = perf_evlist__last(temp_evlist);
+
+	if (!evlist || cpu_map__empty(evlist->cpus)) {
+		struct cpu_map *cpus = cpu_map__new(NULL);
+
+		cpu =  cpus ? cpus->map[0] : 0;
+		cpu_map__put(cpus);
+	} else {
+		cpu = evlist->cpus->map[0];
+	}
+
+	while (1) {
+		fd = sys_perf_event_open(&evsel->attr, pid, cpu, -1,
+					 perf_event_open_cloexec_flag());
+		if (fd < 0) {
+			if (pid == -1 && errno == EACCES) {
+				pid = 0;
+				continue;
+			}
+			goto out_delete;
+		}
+		break;
+	}
+	close(fd);
+	ret = true;
+
+out_delete:
+	perf_evlist__delete(temp_evlist);
+	return ret;
+}
+
+int record__parse_freq(const struct option *opt, const char *str, int unset __maybe_unused)
+{
+	unsigned int freq;
+	struct record_opts *opts = opt->value;
+
+	if (!str)
+		return -EINVAL;
+
+	if (strcasecmp(str, "max") == 0) {
+		if (get_max_rate(&freq)) {
+			pr_err("couldn't read /proc/sys/kernel/perf_event_max_sample_rate\n");
+			return -1;
+		}
+		pr_info("info: Using a maximum frequency rate of %'d Hz\n", freq);
+	} else {
+		freq = atoi(str);
+	}
+
+	opts->user_freq = freq;
+	return 0;
+}