1 files changed, 661 insertions, 0 deletions

diff --git a/tools/perf/util/intel-tpebs.c b/tools/perf/util/intel-tpebs.c
new file mode 100644
index 000000000000..3b92ebf5c112
--- /dev/null
+++ b/tools/perf/util/intel-tpebs.c
@@ -0,0 +1,661 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * intel_tpebs.c: Intel TPEBS support
+ */
+
+#include <api/fs/fs.h>
+#include <sys/param.h>
+#include <subcmd/run-command.h>
+#include <thread.h>
+#include "intel-tpebs.h"
+#include <linux/list.h>
+#include <linux/zalloc.h>
+#include <linux/err.h>
+#include "sample.h"
+#include "counts.h"
+#include "debug.h"
+#include "evlist.h"
+#include "evsel.h"
+#include "mutex.h"
+#include "session.h"
+#include "stat.h"
+#include "tool.h"
+#include "cpumap.h"
+#include "metricgroup.h"
+#include "stat.h"
+#include <sys/stat.h>
+#include <sys/file.h>
+#include <poll.h>
+#include <math.h>
+
+#define PERF_DATA		"-"
+
+bool tpebs_recording;
+enum tpebs_mode tpebs_mode;
+static LIST_HEAD(tpebs_results);
+static pthread_t tpebs_reader_thread;
+static struct child_process tpebs_cmd;
+static int control_fd[2], ack_fd[2];
+static struct mutex tpebs_mtx;
+
+struct tpebs_retire_lat {
+	struct list_head nd;
+	/** @evsel: The evsel that opened the retire_lat event. */
+	struct evsel *evsel;
+	/** @event: Event passed to perf record. */
+	char *event;
+	/** @stats: Recorded retirement latency stats. */
+	struct stats stats;
+	/** @last: Last retirement latency read. */
+	uint64_t last;
+	/* Has the event been sent to perf record? */
+	bool started;
+};
+
+static void tpebs_mtx_init(void)
+{
+	mutex_init(&tpebs_mtx);
+}
+
+static struct mutex *tpebs_mtx_get(void)
+{
+	static pthread_once_t tpebs_mtx_once = PTHREAD_ONCE_INIT;
+
+	pthread_once(&tpebs_mtx_once, tpebs_mtx_init);
+	return &tpebs_mtx;
+}
+
+static struct tpebs_retire_lat *tpebs_retire_lat__find(struct evsel *evsel)
+	EXCLUSIVE_LOCKS_REQUIRED(tpebs_mtx_get());
+
+static int evsel__tpebs_start_perf_record(struct evsel *evsel)
+{
+	const char **record_argv;
+	int tpebs_event_size = 0, i = 0, ret;
+	char control_fd_buf[32];
+	char cpumap_buf[50];
+	struct tpebs_retire_lat *t;
+
+	list_for_each_entry(t, &tpebs_results, nd)
+		tpebs_event_size++;
+
+	record_argv = malloc((10 + 2 * tpebs_event_size) * sizeof(*record_argv));
+	if (!record_argv)
+		return -ENOMEM;
+
+	record_argv[i++] = "perf";
+	record_argv[i++] = "record";
+	record_argv[i++] = "-W";
+	record_argv[i++] = "--synth=no";
+
+	scnprintf(control_fd_buf, sizeof(control_fd_buf), "--control=fd:%d,%d",
+		  control_fd[0], ack_fd[1]);
+	record_argv[i++] = control_fd_buf;
+
+	record_argv[i++] = "-o";
+	record_argv[i++] = PERF_DATA;
+
+	if (!perf_cpu_map__is_any_cpu_or_is_empty(evsel->evlist->core.user_requested_cpus)) {
+		cpu_map__snprint(evsel->evlist->core.user_requested_cpus, cpumap_buf,
+				 sizeof(cpumap_buf));
+		record_argv[i++] = "-C";
+		record_argv[i++] = cpumap_buf;
+	}
+
+	list_for_each_entry(t, &tpebs_results, nd) {
+		record_argv[i++] = "-e";
+		record_argv[i++] = t->event;
+	}
+	record_argv[i++] = NULL;
+	assert(i == 10 + 2 * tpebs_event_size || i == 8 + 2 * tpebs_event_size);
+	/* Note, no workload given so system wide is implied. */
+
+	assert(tpebs_cmd.pid == 0);
+	tpebs_cmd.argv = record_argv;
+	tpebs_cmd.out = -1;
+	ret = start_command(&tpebs_cmd);
+	zfree(&tpebs_cmd.argv);
+	list_for_each_entry(t, &tpebs_results, nd)
+		t->started = true;
+
+	return ret;
+}
+
+static bool is_child_pid(pid_t parent, pid_t child)
+{
+	if (parent < 0 || child < 0)
+		return false;
+
+	while (true) {
+		char path[PATH_MAX];
+		char line[256];
+		FILE *fp;
+
+new_child:
+		if (parent == child)
+			return true;
+
+		if (child <= 0)
+			return false;
+
+		scnprintf(path, sizeof(path), "%s/%d/status", procfs__mountpoint(), child);
+		fp = fopen(path, "r");
+		if (!fp) {
+			/* Presumably the process went away. Assume not a child. */
+			return false;
+		}
+		while (fgets(line, sizeof(line), fp) != NULL) {
+			if (strncmp(line, "PPid:", 5) == 0) {
+				fclose(fp);
+				if (sscanf(line + 5, "%d", &child) != 1) {
+					/* Unexpected error parsing. */
+					return false;
+				}
+				goto new_child;
+			}
+		}
+		/* Unexpected EOF. */
+		fclose(fp);
+		return false;
+	}
+}
+
+static bool should_ignore_sample(const struct perf_sample *sample, const struct tpebs_retire_lat *t)
+{
+	pid_t workload_pid, sample_pid = sample->pid;
+
+	/*
+	 * During evlist__purge the evlist will be removed prior to the
+	 * evsel__exit calling evsel__tpebs_close and taking the
+	 * tpebs_mtx. Avoid a segfault by ignoring samples in this case.
+	 */
+	if (t->evsel->evlist == NULL)
+		return true;
+
+	workload_pid = t->evsel->evlist->workload.pid;
+	if (workload_pid < 0 || workload_pid == sample_pid)
+		return false;
+
+	if (!t->evsel->core.attr.inherit)
+		return true;
+
+	return !is_child_pid(workload_pid, sample_pid);
+}
+
+static int process_sample_event(const struct perf_tool *tool __maybe_unused,
+				union perf_event *event __maybe_unused,
+				struct perf_sample *sample,
+				struct evsel *evsel,
+				struct machine *machine __maybe_unused)
+{
+	struct tpebs_retire_lat *t;
+
+	mutex_lock(tpebs_mtx_get());
+	if (tpebs_cmd.pid == 0) {
+		/* Record has terminated. */
+		mutex_unlock(tpebs_mtx_get());
+		return 0;
+	}
+	t = tpebs_retire_lat__find(evsel);
+	if (!t) {
+		mutex_unlock(tpebs_mtx_get());
+		return -EINVAL;
+	}
+	if (should_ignore_sample(sample, t)) {
+		mutex_unlock(tpebs_mtx_get());
+		return 0;
+	}
+	/*
+	 * Need to handle per core results? We are assuming average retire
+	 * latency value will be used. Save the number of samples and the sum of
+	 * retire latency value for each event.
+	 */
+	t->last = sample->retire_lat;
+	update_stats(&t->stats, sample->retire_lat);
+	mutex_unlock(tpebs_mtx_get());
+	return 0;
+}
+
+static int process_feature_event(struct perf_session *session,
+				 union perf_event *event)
+{
+	if (event->feat.feat_id < HEADER_LAST_FEATURE)
+		return perf_event__process_feature(session, event);
+	return 0;
+}
+
+static void *__sample_reader(void *arg __maybe_unused)
+{
+	struct perf_session *session;
+	struct perf_data data = {
+		.mode = PERF_DATA_MODE_READ,
+		.path = PERF_DATA,
+		.file.fd = tpebs_cmd.out,
+	};
+	struct perf_tool tool;
+
+	perf_tool__init(&tool, /*ordered_events=*/false);
+	tool.sample = process_sample_event;
+	tool.feature = process_feature_event;
+	tool.attr = perf_event__process_attr;
+
+	session = perf_session__new(&data, &tool);
+	if (IS_ERR(session))
+		return NULL;
+	perf_session__process_events(session);
+	perf_session__delete(session);
+
+	return NULL;
+}
+
+static int tpebs_send_record_cmd(const char *msg) EXCLUSIVE_LOCKS_REQUIRED(tpebs_mtx_get())
+{
+	struct pollfd pollfd = { .events = POLLIN, };
+	int ret, len, retries = 0;
+	char ack_buf[8];
+
+	/* Check if the command exited before the send, done with the lock held. */
+	if (tpebs_cmd.pid == 0)
+		return 0;
+
+	/*
+	 * Let go of the lock while sending/receiving as blocking can starve the
+	 * sample reading thread.
+	 */
+	mutex_unlock(tpebs_mtx_get());
+
+	/* Send perf record command.*/
+	len = strlen(msg);
+	ret = write(control_fd[1], msg, len);
+	if (ret != len) {
+		pr_err("perf record control write control message '%s' failed\n", msg);
+		ret = -EPIPE;
+		goto out;
+	}
+
+	if (!strcmp(msg, EVLIST_CTL_CMD_STOP_TAG)) {
+		ret = 0;
+		goto out;
+	}
+
+	/* Wait for an ack. */
+	pollfd.fd = ack_fd[0];
+
+	/*
+	 * We need this poll to ensure the ack_fd PIPE will not hang
+	 * when perf record failed for any reason. The timeout value
+	 * 3000ms is an empirical selection.
+	 */
+again:
+	if (!poll(&pollfd, 1, 500)) {
+		if (check_if_command_finished(&tpebs_cmd)) {
+			ret = 0;
+			goto out;
+		}
+
+		if (retries++ < 6)
+			goto again;
+		pr_err("tpebs failed: perf record ack timeout for '%s'\n", msg);
+		ret = -ETIMEDOUT;
+		goto out;
+	}
+
+	if (!(pollfd.revents & POLLIN)) {
+		if (check_if_command_finished(&tpebs_cmd)) {
+			ret = 0;
+			goto out;
+		}
+
+		pr_err("tpebs failed: did not received an ack for '%s'\n", msg);
+		ret = -EPIPE;
+		goto out;
+	}
+
+	ret = read(ack_fd[0], ack_buf, sizeof(ack_buf));
+	if (ret > 0)
+		ret = strcmp(ack_buf, EVLIST_CTL_CMD_ACK_TAG);
+	else
+		pr_err("tpebs: perf record control ack failed\n");
+out:
+	/* Re-take lock as expected by caller. */
+	mutex_lock(tpebs_mtx_get());
+	return ret;
+}
+
+/*
+ * tpebs_stop - stop the sample data read thread and the perf record process.
+ */
+static int tpebs_stop(void) EXCLUSIVE_LOCKS_REQUIRED(tpebs_mtx_get())
+{
+	int ret = 0;
+
+	/* Like tpebs_start, we should only run tpebs_end once. */
+	if (tpebs_cmd.pid != 0) {
+		tpebs_send_record_cmd(EVLIST_CTL_CMD_STOP_TAG);
+		tpebs_cmd.pid = 0;
+		mutex_unlock(tpebs_mtx_get());
+		pthread_join(tpebs_reader_thread, NULL);
+		mutex_lock(tpebs_mtx_get());
+		close(control_fd[0]);
+		close(control_fd[1]);
+		close(ack_fd[0]);
+		close(ack_fd[1]);
+		close(tpebs_cmd.out);
+		ret = finish_command(&tpebs_cmd);
+		tpebs_cmd.pid = 0;
+		if (ret == -ERR_RUN_COMMAND_WAITPID_SIGNAL)
+			ret = 0;
+	}
+	return ret;
+}
+
+/**
+ * evsel__tpebs_event() - Create string event encoding to pass to `perf record`.
+ */
+static int evsel__tpebs_event(struct evsel *evsel, char **event)
+{
+	char *name, *modifier;
+	int ret;
+
+	name = strdup(evsel->name);
+	if (!name)
+		return -ENOMEM;
+
+	modifier = strrchr(name, 'R');
+	if (!modifier) {
+		ret = -EINVAL;
+		goto out;
+	}
+	*modifier = 'p';
+	modifier = strchr(name, ':');
+	if (!modifier)
+		modifier = strrchr(name, '/');
+	if (!modifier) {
+		ret = -EINVAL;
+		goto out;
+	}
+	*modifier = '\0';
+	if (asprintf(event, "%s/name=tpebs_event_%p/%s", name, evsel, modifier + 1) > 0)
+		ret = 0;
+	else
+		ret = -ENOMEM;
+out:
+	if (ret)
+		pr_err("Tpebs event modifier broken '%s'\n", evsel->name);
+	free(name);
+	return ret;
+}
+
+static struct tpebs_retire_lat *tpebs_retire_lat__new(struct evsel *evsel)
+{
+	struct tpebs_retire_lat *result = zalloc(sizeof(*result));
+	int ret;
+
+	if (!result)
+		return NULL;
+
+	ret = evsel__tpebs_event(evsel, &result->event);
+	if (ret) {
+		free(result);
+		return NULL;
+	}
+	result->evsel = evsel;
+	return result;
+}
+
+static void tpebs_retire_lat__delete(struct tpebs_retire_lat *r)
+{
+	zfree(&r->event);
+	free(r);
+}
+
+static struct tpebs_retire_lat *tpebs_retire_lat__find(struct evsel *evsel)
+{
+	struct tpebs_retire_lat *t;
+	unsigned long num;
+	const char *evsel_name;
+
+	/*
+	 * Evsels will match for evlist with the retirement latency event. The
+	 * name with "tpebs_event_" prefix will be present on events being read
+	 * from `perf record`.
+	 */
+	if (evsel__is_retire_lat(evsel)) {
+		list_for_each_entry(t, &tpebs_results, nd) {
+			if (t->evsel == evsel)
+				return t;
+		}
+		return NULL;
+	}
+	evsel_name = strstr(evsel->name, "tpebs_event_");
+	if (!evsel_name) {
+		/* Unexpected that the perf record should have other events. */
+		return NULL;
+	}
+	errno = 0;
+	num = strtoull(evsel_name + 12, NULL, 16);
+	if (errno) {
+		pr_err("Bad evsel for tpebs find '%s'\n", evsel->name);
+		return NULL;
+	}
+	list_for_each_entry(t, &tpebs_results, nd) {
+		if ((unsigned long)t->evsel == num)
+			return t;
+	}
+	return NULL;
+}
+
+/**
+ * evsel__tpebs_prepare - create tpebs data structures ready for opening.
+ * @evsel: retire_latency evsel, all evsels on its list will be prepared.
+ */
+static int evsel__tpebs_prepare(struct evsel *evsel)
+{
+	struct evsel *pos;
+	struct tpebs_retire_lat *tpebs_event;
+
+	mutex_lock(tpebs_mtx_get());
+	tpebs_event = tpebs_retire_lat__find(evsel);
+	if (tpebs_event) {
+		/* evsel, or an identically named one, was already prepared. */
+		mutex_unlock(tpebs_mtx_get());
+		return 0;
+	}
+	tpebs_event = tpebs_retire_lat__new(evsel);
+	if (!tpebs_event) {
+		mutex_unlock(tpebs_mtx_get());
+		return -ENOMEM;
+	}
+	list_add_tail(&tpebs_event->nd, &tpebs_results);
+	mutex_unlock(tpebs_mtx_get());
+
+	/*
+	 * Eagerly prepare all other evsels on the list to try to ensure that by
+	 * open they are all known.
+	 */
+	evlist__for_each_entry(evsel->evlist, pos) {
+		int ret;
+
+		if (pos == evsel || !pos->retire_lat)
+			continue;
+
+		ret = evsel__tpebs_prepare(pos);
+		if (ret)
+			return ret;
+	}
+	return 0;
+}
+
+/**
+ * evsel__tpebs_open - starts tpebs execution.
+ * @evsel: retire_latency evsel, all evsels on its list will be selected. Each
+ *         evsel is sampled to get the average retire_latency value.
+ */
+int evsel__tpebs_open(struct evsel *evsel)
+{
+	int ret;
+	bool tpebs_empty;
+
+	/* We should only run tpebs_start when tpebs_recording is enabled. */
+	if (!tpebs_recording)
+		return 0;
+	/* Only start the events once. */
+	if (tpebs_cmd.pid != 0) {
+		struct tpebs_retire_lat *t;
+		bool valid;
+
+		mutex_lock(tpebs_mtx_get());
+		t = tpebs_retire_lat__find(evsel);
+		valid = t && t->started;
+		mutex_unlock(tpebs_mtx_get());
+		/* May fail as the event wasn't started. */
+		return valid ? 0 : -EBUSY;
+	}
+
+	ret = evsel__tpebs_prepare(evsel);
+	if (ret)
+		return ret;
+
+	mutex_lock(tpebs_mtx_get());
+	tpebs_empty = list_empty(&tpebs_results);
+	if (!tpebs_empty) {
+		/*Create control and ack fd for --control*/
+		if (pipe(control_fd) < 0) {
+			pr_err("tpebs: Failed to create control fifo");
+			ret = -1;
+			goto out;
+		}
+		if (pipe(ack_fd) < 0) {
+			pr_err("tpebs: Failed to create control fifo");
+			ret = -1;
+			goto out;
+		}
+
+		ret = evsel__tpebs_start_perf_record(evsel);
+		if (ret)
+			goto out;
+
+		if (pthread_create(&tpebs_reader_thread, /*attr=*/NULL, __sample_reader,
+				   /*arg=*/NULL)) {
+			kill(tpebs_cmd.pid, SIGTERM);
+			close(tpebs_cmd.out);
+			pr_err("Could not create thread to process sample data.\n");
+			ret = -1;
+			goto out;
+		}
+		ret = tpebs_send_record_cmd(EVLIST_CTL_CMD_ENABLE_TAG);
+	}
+out:
+	if (ret) {
+		struct tpebs_retire_lat *t = tpebs_retire_lat__find(evsel);
+
+		list_del_init(&t->nd);
+		tpebs_retire_lat__delete(t);
+	}
+	mutex_unlock(tpebs_mtx_get());
+	return ret;
+}
+
+int evsel__tpebs_read(struct evsel *evsel, int cpu_map_idx, int thread)
+{
+	struct perf_counts_values *count, *old_count = NULL;
+	struct tpebs_retire_lat *t;
+	uint64_t val;
+	int ret;
+
+	/* Only set retire_latency value to the first CPU and thread. */
+	if (cpu_map_idx != 0 || thread != 0)
+		return 0;
+
+	if (evsel->prev_raw_counts)
+		old_count = perf_counts(evsel->prev_raw_counts, cpu_map_idx, thread);
+
+	count = perf_counts(evsel->counts, cpu_map_idx, thread);
+
+	mutex_lock(tpebs_mtx_get());
+	t = tpebs_retire_lat__find(evsel);
+	/*
+	 * If reading the first tpebs result, send a ping to the record
+	 * process. Allow the sample reader a chance to read by releasing and
+	 * reacquiring the lock.
+	 */
+	if (t && &t->nd == tpebs_results.next) {
+		ret = tpebs_send_record_cmd(EVLIST_CTL_CMD_PING_TAG);
+		mutex_unlock(tpebs_mtx_get());
+		if (ret)
+			return ret;
+		mutex_lock(tpebs_mtx_get());
+	}
+	if (t == NULL || t->stats.n == 0) {
+		/* No sample data, use default. */
+		if (tpebs_recording) {
+			pr_warning_once(
+				"Using precomputed retirement latency data as no samples\n");
+		}
+		val = 0;
+		switch (tpebs_mode) {
+		case TPEBS_MODE__MIN:
+			val = rint(evsel->retirement_latency.min);
+			break;
+		case TPEBS_MODE__MAX:
+			val = rint(evsel->retirement_latency.max);
+			break;
+		default:
+		case TPEBS_MODE__LAST:
+		case TPEBS_MODE__MEAN:
+			val = rint(evsel->retirement_latency.mean);
+			break;
+		}
+	} else {
+		switch (tpebs_mode) {
+		case TPEBS_MODE__MIN:
+			val = t->stats.min;
+			break;
+		case TPEBS_MODE__MAX:
+			val = t->stats.max;
+			break;
+		case TPEBS_MODE__LAST:
+			val = t->last;
+			break;
+		default:
+		case TPEBS_MODE__MEAN:
+			val = rint(t->stats.mean);
+			break;
+		}
+	}
+	mutex_unlock(tpebs_mtx_get());
+
+	if (old_count) {
+		count->val = old_count->val + val;
+		count->run = old_count->run + 1;
+		count->ena = old_count->ena + 1;
+	} else {
+		count->val = val;
+		count->run++;
+		count->ena++;
+	}
+	return 0;
+}
+
+/**
+ * evsel__tpebs_close() - delete tpebs related data. If the last event, stop the
+ * created thread and process by calling tpebs_stop().
+ *
+ * This function is called in evsel__close() to be symmetric with
+ * evsel__tpebs_open() being called in evsel__open().
+ */
+void evsel__tpebs_close(struct evsel *evsel)
+{
+	struct tpebs_retire_lat *t;
+
+	mutex_lock(tpebs_mtx_get());
+	t = tpebs_retire_lat__find(evsel);
+	if (t) {
+		list_del_init(&t->nd);
+		tpebs_retire_lat__delete(t);
+
+		if (list_empty(&tpebs_results))
+			tpebs_stop();
+	}
+	mutex_unlock(tpebs_mtx_get());
+}