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acb65150a4
With the hardware TopDown metrics feature, sample-read feature should be supported for a topdown group, e.g., sample a non-topdown event and read a topdown metric group. But the current perf record code errors out. For a topdown metric group, the slots event must be the leader of the group, but the leader slots event doesn't support sampling. To support sample-read the topdown metric group, use the 2nd event of the group as the "leader" for the purposes of sampling. Only the platform with Topdown metic feature supports sample-read the topdown group. Add arch_topdown_sample_read() to indicate whether the topdown group supports sample-read. Signed-off-by: Kan Liang <kan.liang@linux.intel.com> Acked-by: Jiri Olsa <jolsa@redhat.com> Acked-by: Namhyung Kim <namhyung@kernel.org> Cc: Andi Kleen <ak@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lore.kernel.org/lkml/20200911144808.27603-3-kan.liang@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
288 lines
7.3 KiB
C
288 lines
7.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include "debug.h"
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#include "evlist.h"
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#include "evsel.h"
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#include "evsel_config.h"
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#include "parse-events.h"
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#include <errno.h>
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#include <limits.h>
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#include <stdlib.h>
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#include <api/fs/fs.h>
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#include <subcmd/parse-options.h>
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#include <perf/cpumap.h>
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#include "cloexec.h"
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#include "util/perf_api_probe.h"
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#include "record.h"
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#include "../perf-sys.h"
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#include "topdown.h"
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/*
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* evsel__config_leader_sampling() uses special rules for leader sampling.
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* However, if the leader is an AUX area event, then assume the event to sample
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* is the next event.
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*/
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static struct evsel *evsel__read_sampler(struct evsel *evsel, struct evlist *evlist)
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{
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struct evsel *leader = evsel->leader;
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if (evsel__is_aux_event(leader) || arch_topdown_sample_read(leader)) {
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evlist__for_each_entry(evlist, evsel) {
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if (evsel->leader == leader && evsel != evsel->leader)
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return evsel;
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}
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}
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return leader;
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}
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static u64 evsel__config_term_mask(struct evsel *evsel)
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{
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struct evsel_config_term *term;
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struct list_head *config_terms = &evsel->config_terms;
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u64 term_types = 0;
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list_for_each_entry(term, config_terms, list) {
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term_types |= 1 << term->type;
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}
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return term_types;
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}
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static void evsel__config_leader_sampling(struct evsel *evsel, struct evlist *evlist)
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{
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struct perf_event_attr *attr = &evsel->core.attr;
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struct evsel *leader = evsel->leader;
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struct evsel *read_sampler;
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u64 term_types, freq_mask;
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if (!leader->sample_read)
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return;
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read_sampler = evsel__read_sampler(evsel, evlist);
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if (evsel == read_sampler)
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return;
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term_types = evsel__config_term_mask(evsel);
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/*
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* Disable sampling for all group members except those with explicit
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* config terms or the leader. In the case of an AUX area event, the 2nd
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* event in the group is the one that 'leads' the sampling.
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*/
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freq_mask = (1 << EVSEL__CONFIG_TERM_FREQ) | (1 << EVSEL__CONFIG_TERM_PERIOD);
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if ((term_types & freq_mask) == 0) {
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attr->freq = 0;
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attr->sample_freq = 0;
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attr->sample_period = 0;
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}
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if ((term_types & (1 << EVSEL__CONFIG_TERM_OVERWRITE)) == 0)
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attr->write_backward = 0;
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/*
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* We don't get a sample for slave events, we make them when delivering
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* the group leader sample. Set the slave event to follow the master
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* sample_type to ease up reporting.
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* An AUX area event also has sample_type requirements, so also include
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* the sample type bits from the leader's sample_type to cover that
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* case.
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*/
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attr->sample_type = read_sampler->core.attr.sample_type |
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leader->core.attr.sample_type;
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}
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void perf_evlist__config(struct evlist *evlist, struct record_opts *opts,
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struct callchain_param *callchain)
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{
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struct evsel *evsel;
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bool use_sample_identifier = false;
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bool use_comm_exec;
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bool sample_id = opts->sample_id;
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/*
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* Set the evsel leader links before we configure attributes,
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* since some might depend on this info.
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*/
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if (opts->group)
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perf_evlist__set_leader(evlist);
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if (evlist->core.cpus->map[0] < 0)
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opts->no_inherit = true;
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use_comm_exec = perf_can_comm_exec();
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evlist__for_each_entry(evlist, evsel) {
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evsel__config(evsel, opts, callchain);
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if (evsel->tracking && use_comm_exec)
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evsel->core.attr.comm_exec = 1;
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}
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/* Configure leader sampling here now that the sample type is known */
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evlist__for_each_entry(evlist, evsel)
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evsel__config_leader_sampling(evsel, evlist);
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if (opts->full_auxtrace) {
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/*
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* Need to be able to synthesize and parse selected events with
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* arbitrary sample types, which requires always being able to
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* match the id.
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*/
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use_sample_identifier = perf_can_sample_identifier();
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sample_id = true;
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} else if (evlist->core.nr_entries > 1) {
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struct evsel *first = evlist__first(evlist);
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evlist__for_each_entry(evlist, evsel) {
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if (evsel->core.attr.sample_type == first->core.attr.sample_type)
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continue;
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use_sample_identifier = perf_can_sample_identifier();
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break;
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}
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sample_id = true;
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}
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if (sample_id) {
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evlist__for_each_entry(evlist, evsel)
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evsel__set_sample_id(evsel, use_sample_identifier);
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}
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perf_evlist__set_id_pos(evlist);
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}
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static int get_max_rate(unsigned int *rate)
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{
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return sysctl__read_int("kernel/perf_event_max_sample_rate", (int *)rate);
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}
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static int record_opts__config_freq(struct record_opts *opts)
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{
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bool user_freq = opts->user_freq != UINT_MAX;
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unsigned int max_rate;
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if (opts->user_interval != ULLONG_MAX)
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opts->default_interval = opts->user_interval;
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if (user_freq)
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opts->freq = opts->user_freq;
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/*
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* User specified count overrides default frequency.
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*/
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if (opts->default_interval)
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opts->freq = 0;
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else if (opts->freq) {
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opts->default_interval = opts->freq;
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} else {
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pr_err("frequency and count are zero, aborting\n");
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return -1;
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}
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if (get_max_rate(&max_rate))
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return 0;
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/*
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* User specified frequency is over current maximum.
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*/
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if (user_freq && (max_rate < opts->freq)) {
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if (opts->strict_freq) {
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pr_err("error: Maximum frequency rate (%'u Hz) exceeded.\n"
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" Please use -F freq option with a lower value or consider\n"
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" tweaking /proc/sys/kernel/perf_event_max_sample_rate.\n",
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max_rate);
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return -1;
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} else {
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pr_warning("warning: Maximum frequency rate (%'u Hz) exceeded, throttling from %'u Hz to %'u Hz.\n"
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" The limit can be raised via /proc/sys/kernel/perf_event_max_sample_rate.\n"
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" The kernel will lower it when perf's interrupts take too long.\n"
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" Use --strict-freq to disable this throttling, refusing to record.\n",
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max_rate, opts->freq, max_rate);
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opts->freq = max_rate;
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}
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}
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/*
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* Default frequency is over current maximum.
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*/
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if (max_rate < opts->freq) {
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pr_warning("Lowering default frequency rate to %u.\n"
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"Please consider tweaking "
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"/proc/sys/kernel/perf_event_max_sample_rate.\n",
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max_rate);
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opts->freq = max_rate;
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}
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return 0;
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}
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int record_opts__config(struct record_opts *opts)
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{
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return record_opts__config_freq(opts);
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}
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bool perf_evlist__can_select_event(struct evlist *evlist, const char *str)
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{
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struct evlist *temp_evlist;
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struct evsel *evsel;
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int err, fd, cpu;
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bool ret = false;
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pid_t pid = -1;
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temp_evlist = evlist__new();
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if (!temp_evlist)
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return false;
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err = parse_events(temp_evlist, str, NULL);
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if (err)
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goto out_delete;
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evsel = evlist__last(temp_evlist);
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if (!evlist || perf_cpu_map__empty(evlist->core.cpus)) {
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struct perf_cpu_map *cpus = perf_cpu_map__new(NULL);
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cpu = cpus ? cpus->map[0] : 0;
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perf_cpu_map__put(cpus);
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} else {
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cpu = evlist->core.cpus->map[0];
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}
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while (1) {
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fd = sys_perf_event_open(&evsel->core.attr, pid, cpu, -1,
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perf_event_open_cloexec_flag());
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if (fd < 0) {
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if (pid == -1 && errno == EACCES) {
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pid = 0;
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continue;
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}
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goto out_delete;
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}
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break;
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}
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close(fd);
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ret = true;
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out_delete:
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evlist__delete(temp_evlist);
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return ret;
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}
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int record__parse_freq(const struct option *opt, const char *str, int unset __maybe_unused)
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{
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unsigned int freq;
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struct record_opts *opts = opt->value;
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if (!str)
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return -EINVAL;
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if (strcasecmp(str, "max") == 0) {
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if (get_max_rate(&freq)) {
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pr_err("couldn't read /proc/sys/kernel/perf_event_max_sample_rate\n");
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return -1;
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}
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pr_info("info: Using a maximum frequency rate of %'d Hz\n", freq);
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} else {
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freq = atoi(str);
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}
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opts->user_freq = freq;
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return 0;
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}
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