// SPDX-License-Identifier: GPL-2.0
#include "debug.h"
#include "evlist.h"
#include "evsel.h"
#include "evsel_config.h"
#include "parse-events.h"
#include <errno.h>
#include <limits.h>
#include <stdlib.h>
#include <api/fs/fs.h>
#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"
#include "topdown.h"
#include "map_symbol.h"
#include "mem-events.h"
/*
* 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 evsel *leader = evsel__leader(evsel);
if (evsel__is_aux_event(leader) || arch_topdown_sample_read(leader) ||
is_mem_loads_aux_event(leader)) {
evlist__for_each_entry(evlist, evsel) {
if (evsel__leader(evsel) == leader && evsel != evsel__leader(evsel))
return evsel;
}
}
return leader;
}
static u64 evsel__config_term_mask(struct evsel *evsel)
{
struct evsel_config_term *term;
struct list_head *config_terms = &evsel->config_terms;
u64 term_types = 0;
list_for_each_entry(term, config_terms, list) {
term_types |= 1 << term->type;
}
return term_types;
}
static void evsel__config_leader_sampling(struct evsel *evsel, struct evlist *evlist)
{
struct perf_event_attr *attr = &evsel->core.attr;
struct evsel *leader = evsel__leader(evsel);
struct evsel *read_sampler;
u64 term_types, freq_mask;
if (!leader->sample_read)
return;
read_sampler = evsel__read_sampler(evsel, evlist);
if (evsel == read_sampler)
return;
term_types = evsel__config_term_mask(evsel);
/*
* Disable sampling for all group members except those with explicit
* config terms or the leader. In the case of an AUX area event, the 2nd
* event in the group is the one that 'leads' the sampling.
*/
freq_mask = (1 << EVSEL__CONFIG_TERM_FREQ) | (1 << EVSEL__CONFIG_TERM_PERIOD);
if ((term_types & freq_mask) == 0) {
attr->freq = 0;
attr->sample_freq = 0;
attr->sample_period = 0;
}
if ((term_types & (1 << EVSEL__CONFIG_TERM_OVERWRITE)) == 0)
attr->write_backward = 0;
/*
* 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 evlist__config(struct evlist *evlist, struct record_opts *opts, struct callchain_param *callchain)
{
struct evsel *evsel;
bool use_sample_identifier = false;
bool use_comm_exec;
bool sample_id = opts->sample_id;
if (perf_cpu_map__cpu(evlist->core.user_requested_cpus, 0).cpu < 0)
opts->no_inherit = true;
use_comm_exec = perf_can_comm_exec();
evlist__for_each_entry(evlist, evsel) {
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 || opts->sample_identifier) {
/*
* 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->core.nr_entries > 1) {
struct evsel *first = evlist__first(evlist);
evlist__for_each_entry(evlist, evsel) {
if (evsel->core.attr.sample_type == first->core.attr.sample_type)
continue;
use_sample_identifier = perf_can_sample_identifier();
break;
}
sample_id = true;
}
if (sample_id) {
evlist__for_each_entry(evlist, evsel)
evsel__set_sample_id(evsel, use_sample_identifier);
}
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;
bool user_interval = opts->user_interval != ULLONG_MAX;
unsigned int max_rate;
if (user_interval && user_freq) {
pr_err("cannot set frequency and period at the same time\n");
return -1;
}
if (user_interval)
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 from %u to %u.\n"
"Please consider tweaking "
"/proc/sys/kernel/perf_event_max_sample_rate.\n",
opts->freq, max_rate);
opts->freq = max_rate;
}
return 0;
}
int record_opts__config(struct record_opts *opts)
{
return record_opts__config_freq(opts);
}
bool evlist__can_select_event(struct evlist *evlist, const char *str)
{
struct evlist *temp_evlist;
struct evsel *evsel;
int err, fd;
struct perf_cpu cpu = { .cpu = 0 };
bool ret = false;
pid_t pid = -1;
temp_evlist = evlist__new();
if (!temp_evlist)
return false;
err = parse_event(temp_evlist, str);
if (err)
goto out_delete;
evsel = evlist__last(temp_evlist);
if (!evlist || perf_cpu_map__is_any_cpu_or_is_empty(evlist->core.user_requested_cpus)) {
struct perf_cpu_map *cpus = perf_cpu_map__new_online_cpus();
if (cpus)
cpu = perf_cpu_map__cpu(cpus, 0);
perf_cpu_map__put(cpus);
} else {
cpu = perf_cpu_map__cpu(evlist->core.user_requested_cpus, 0);
}
while (1) {
fd = sys_perf_event_open(&evsel->core.attr, pid, cpu.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:
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;
}
Codebase Browser
linux