linux/tools/perf/util/record.c

327 lines
7.1 KiB
C

// 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;
}