// SPDX-License-Identifier: GPL-2.0-only
/*
* intel_tpebs.c: Intel TPEBS support
*/
#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 "debug.h"
#include "evlist.h"
#include "evsel.h"
#include "session.h"
#include "tool.h"
#include "cpumap.h"
#include "metricgroup.h"
#include <sys/stat.h>
#include <sys/file.h>
#include <poll.h>
#include <math.h>
#define PERF_DATA "-"
bool tpebs_recording;
static pid_t tpebs_pid = -1;
static size_t tpebs_event_size;
static LIST_HEAD(tpebs_results);
static pthread_t tpebs_reader_thread;
static struct child_process *tpebs_cmd;
struct tpebs_retire_lat {
struct list_head nd;
/* Event name */
const char *name;
/* Event name with the TPEBS modifier R */
const char *tpebs_name;
/* Count of retire_latency values found in sample data */
size_t count;
/* Sum of all the retire_latency values in sample data */
int sum;
/* Average of retire_latency, val = sum / count */
double val;
};
static int get_perf_record_args(const char **record_argv, char buf[],
const char *cpumap_buf)
{
struct tpebs_retire_lat *e;
int i = 0;
pr_debug("tpebs: Prepare perf record for retire_latency\n");
record_argv[i++] = "perf";
record_argv[i++] = "record";
record_argv[i++] = "-W";
record_argv[i++] = "--synth=no";
record_argv[i++] = buf;
if (!cpumap_buf) {
pr_err("tpebs: Require cpumap list to run sampling\n");
return -ECANCELED;
}
/* Use -C when cpumap_buf is not "-1" */
if (strcmp(cpumap_buf, "-1")) {
record_argv[i++] = "-C";
record_argv[i++] = cpumap_buf;
}
list_for_each_entry(e, &tpebs_results, nd) {
record_argv[i++] = "-e";
record_argv[i++] = e->name;
}
record_argv[i++] = "-o";
record_argv[i++] = PERF_DATA;
return 0;
}
static int prepare_run_command(const char **argv)
{
tpebs_cmd = zalloc(sizeof(struct child_process));
if (!tpebs_cmd)
return -ENOMEM;
tpebs_cmd->argv = argv;
tpebs_cmd->out = -1;
return 0;
}
static int start_perf_record(int control_fd[], int ack_fd[],
const char *cpumap_buf)
{
const char **record_argv;
int ret;
char buf[32];
scnprintf(buf, sizeof(buf), "--control=fd:%d,%d", control_fd[0], ack_fd[1]);
record_argv = calloc(12 + 2 * tpebs_event_size, sizeof(char *));
if (!record_argv)
return -ENOMEM;
ret = get_perf_record_args(record_argv, buf, cpumap_buf);
if (ret)
goto out;
ret = prepare_run_command(record_argv);
if (ret)
goto out;
ret = start_command(tpebs_cmd);
out:
free(record_argv);
return ret;
}
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)
{
int ret = 0;
const char *evname;
struct tpebs_retire_lat *t;
evname = evsel__name(evsel);
/*
* 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.
*/
list_for_each_entry(t, &tpebs_results, nd) {
if (!strcmp(evname, t->name)) {
t->count += 1;
t->sum += sample->retire_lat;
t->val = (double) t->sum / t->count;
break;
}
}
return ret;
}
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)
{
struct child_process *child = arg;
struct perf_session *session;
struct perf_data data = {
.mode = PERF_DATA_MODE_READ,
.path = PERF_DATA,
.file.fd = child->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;
}
/*
* tpebs_stop - stop the sample data read thread and the perf record process.
*/
static int tpebs_stop(void)
{
int ret = 0;
/* Like tpebs_start, we should only run tpebs_end once. */
if (tpebs_pid != -1) {
kill(tpebs_cmd->pid, SIGTERM);
tpebs_pid = -1;
pthread_join(tpebs_reader_thread, NULL);
close(tpebs_cmd->out);
ret = finish_command(tpebs_cmd);
if (ret == -ERR_RUN_COMMAND_WAITPID_SIGNAL)
ret = 0;
}
return ret;
}
/*
* tpebs_start - start tpebs execution.
* @evsel_list: retire_latency evsels in this list will be selected and sampled
* to get the average retire_latency value.
*
* This function will be called from evlist level later when evlist__open() is
* called consistently.
*/
int tpebs_start(struct evlist *evsel_list)
{
int ret = 0;
struct evsel *evsel;
char cpumap_buf[50];
/*
* We should only run tpebs_start when tpebs_recording is enabled.
* And we should only run it once with all the required events.
*/
if (tpebs_pid != -1 || !tpebs_recording)
return 0;
cpu_map__snprint(evsel_list->core.user_requested_cpus, cpumap_buf, sizeof(cpumap_buf));
/*
* Prepare perf record for sampling event retire_latency before fork and
* prepare workload
*/
evlist__for_each_entry(evsel_list, evsel) {
int i;
char *name;
struct tpebs_retire_lat *new;
if (!evsel->retire_lat)
continue;
pr_debug("tpebs: Retire_latency of event %s is required\n", evsel->name);
for (i = strlen(evsel->name) - 1; i > 0; i--) {
if (evsel->name[i] == 'R')
break;
}
if (i <= 0 || evsel->name[i] != 'R') {
ret = -1;
goto err;
}
name = strdup(evsel->name);
if (!name) {
ret = -ENOMEM;
goto err;
}
name[i] = 'p';
new = zalloc(sizeof(*new));
if (!new) {
ret = -1;
zfree(name);
goto err;
}
new->name = name;
new->tpebs_name = evsel->name;
list_add_tail(&new->nd, &tpebs_results);
tpebs_event_size += 1;
}
if (tpebs_event_size > 0) {
struct pollfd pollfd = { .events = POLLIN, };
int control_fd[2], ack_fd[2], len;
char ack_buf[8];
/*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 = start_perf_record(control_fd, ack_fd, cpumap_buf);
if (ret)
goto out;
tpebs_pid = tpebs_cmd->pid;
if (pthread_create(&tpebs_reader_thread, NULL, __sample_reader, tpebs_cmd)) {
kill(tpebs_cmd->pid, SIGTERM);
close(tpebs_cmd->out);
pr_err("Could not create thread to process sample data.\n");
ret = -1;
goto out;
}
/* Wait for perf record initialization.*/
len = strlen(EVLIST_CTL_CMD_ENABLE_TAG);
ret = write(control_fd[1], EVLIST_CTL_CMD_ENABLE_TAG, len);
if (ret != len) {
pr_err("perf record control write control message failed\n");
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.
*/
if (!poll(&pollfd, 1, 3000)) {
pr_err("tpebs failed: perf record ack timeout\n");
ret = -1;
goto out;
}
if (!(pollfd.revents & POLLIN)) {
pr_err("tpebs failed: did not received an ack\n");
ret = -1;
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");
goto out;
}
out:
close(control_fd[0]);
close(control_fd[1]);
close(ack_fd[0]);
close(ack_fd[1]);
}
err:
if (ret)
tpebs_delete();
return ret;
}
int tpebs_set_evsel(struct evsel *evsel, int cpu_map_idx, int thread)
{
__u64 val;
bool found = false;
struct tpebs_retire_lat *t;
struct perf_counts_values *count;
/* Non reitre_latency evsel should never enter this function. */
if (!evsel__is_retire_lat(evsel))
return -1;
/*
* Need to stop the forked record to ensure get sampled data from the
* PIPE to process and get non-zero retire_lat value for hybrid.
*/
tpebs_stop();
count = perf_counts(evsel->counts, cpu_map_idx, thread);
list_for_each_entry(t, &tpebs_results, nd) {
if (t->tpebs_name == evsel->name ||
(evsel->metric_id && !strcmp(t->tpebs_name, evsel->metric_id))) {
found = true;
break;
}
}
/* Set ena and run to non-zero */
count->ena = count->run = 1;
count->lost = 0;
if (!found) {
/*
* Set default value or 0 when retire_latency for this event is
* not found from sampling data (record_tpebs not set or 0
* sample recorded).
*/
count->val = 0;
return 0;
}
/*
* Only set retire_latency value to the first CPU and thread.
*/
if (cpu_map_idx == 0 && thread == 0)
val = rint(t->val);
else
val = 0;
count->val = val;
return 0;
}
static void tpebs_retire_lat__delete(struct tpebs_retire_lat *r)
{
zfree(&r->name);
free(r);
}
/*
* tpebs_delete - delete tpebs related data and stop the created thread and
* process by calling tpebs_stop().
*
* This function is called from evlist_delete() and also from builtin-stat
* stat_handle_error(). If tpebs_start() is called from places other then perf
* stat, need to ensure tpebs_delete() is also called to safely free mem and
* close the data read thread and the forked perf record process.
*
* This function is also called in evsel__close() to be symmetric with
* tpebs_start() being called in evsel__open(). We will update this call site
* when move tpebs_start() to evlist level.
*/
void tpebs_delete(void)
{
struct tpebs_retire_lat *r, *rtmp;
if (tpebs_pid == -1)
return;
tpebs_stop();
list_for_each_entry_safe(r, rtmp, &tpebs_results, nd) {
list_del_init(&r->nd);
tpebs_retire_lat__delete(r);
}
if (tpebs_cmd) {
free(tpebs_cmd);
tpebs_cmd = NULL;
}
}
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