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67230479b2
Add the handy '-F max' shortcut to reading and using the kernel.perf_event_max_sample_rate value as the user supplied sampling frequency: # perf record -F max sleep 1 info: Using a maximum frequency rate of 15,000 Hz [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.019 MB perf.data (14 samples) ] # sysctl kernel.perf_event_max_sample_rate kernel.perf_event_max_sample_rate = 15000 # perf evlist -v cycles:ppp: size: 112, { sample_period, sample_freq }: 15000, sample_type: IP|TID|TIME|PERIOD, disabled: 1, inherit: 1, mmap: 1, comm: 1, freq: 1, enable_on_exec: 1, task: 1, precise_ip: 3, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1 # perf record -F 10 sleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.019 MB perf.data (4 samples) ] # perf evlist -v cycles:ppp: size: 112, { sample_period, sample_freq }: 10, sample_type: IP|TID|TIME|PERIOD, disabled: 1, inherit: 1, mmap: 1, comm: 1, freq: 1, enable_on_exec: 1, task: 1, precise_ip: 3, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1 # Suggested-by: Ingo Molnar <mingo@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Wang Nan <wangnan0@huawei.com> Link: https://lkml.kernel.org/n/tip-4y0tiuws62c64gp4cf0hme0m@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
313 lines
6.6 KiB
C
313 lines
6.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include "evlist.h"
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#include "evsel.h"
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#include "cpumap.h"
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#include "parse-events.h"
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#include <errno.h>
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#include <api/fs/fs.h>
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#include <subcmd/parse-options.h>
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#include "util.h"
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#include "cloexec.h"
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typedef void (*setup_probe_fn_t)(struct perf_evsel *evsel);
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static int perf_do_probe_api(setup_probe_fn_t fn, int cpu, const char *str)
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{
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struct perf_evlist *evlist;
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struct perf_evsel *evsel;
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unsigned long flags = perf_event_open_cloexec_flag();
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int err = -EAGAIN, fd;
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static pid_t pid = -1;
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evlist = perf_evlist__new();
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if (!evlist)
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return -ENOMEM;
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if (parse_events(evlist, str, NULL))
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goto out_delete;
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evsel = perf_evlist__first(evlist);
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while (1) {
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fd = sys_perf_event_open(&evsel->attr, pid, cpu, -1, flags);
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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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fn(evsel);
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fd = sys_perf_event_open(&evsel->attr, pid, cpu, -1, flags);
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if (fd < 0) {
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if (errno == EINVAL)
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err = -EINVAL;
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goto out_delete;
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}
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close(fd);
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err = 0;
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out_delete:
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perf_evlist__delete(evlist);
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return err;
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}
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static bool perf_probe_api(setup_probe_fn_t fn)
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{
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const char *try[] = {"cycles:u", "instructions:u", "cpu-clock:u", NULL};
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struct cpu_map *cpus;
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int cpu, ret, i = 0;
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cpus = cpu_map__new(NULL);
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if (!cpus)
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return false;
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cpu = cpus->map[0];
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cpu_map__put(cpus);
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do {
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ret = perf_do_probe_api(fn, cpu, try[i++]);
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if (!ret)
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return true;
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} while (ret == -EAGAIN && try[i]);
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return false;
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}
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static void perf_probe_sample_identifier(struct perf_evsel *evsel)
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{
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evsel->attr.sample_type |= PERF_SAMPLE_IDENTIFIER;
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}
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static void perf_probe_comm_exec(struct perf_evsel *evsel)
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{
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evsel->attr.comm_exec = 1;
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}
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static void perf_probe_context_switch(struct perf_evsel *evsel)
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{
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evsel->attr.context_switch = 1;
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}
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bool perf_can_sample_identifier(void)
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{
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return perf_probe_api(perf_probe_sample_identifier);
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}
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static bool perf_can_comm_exec(void)
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{
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return perf_probe_api(perf_probe_comm_exec);
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}
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bool perf_can_record_switch_events(void)
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{
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return perf_probe_api(perf_probe_context_switch);
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}
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bool perf_can_record_cpu_wide(void)
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{
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struct perf_event_attr attr = {
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.type = PERF_TYPE_SOFTWARE,
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.config = PERF_COUNT_SW_CPU_CLOCK,
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.exclude_kernel = 1,
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};
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struct cpu_map *cpus;
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int cpu, fd;
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cpus = cpu_map__new(NULL);
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if (!cpus)
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return false;
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cpu = cpus->map[0];
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cpu_map__put(cpus);
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fd = sys_perf_event_open(&attr, -1, cpu, -1, 0);
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if (fd < 0)
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return false;
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close(fd);
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return true;
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}
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void perf_evlist__config(struct perf_evlist *evlist, struct record_opts *opts,
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struct callchain_param *callchain)
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{
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struct perf_evsel *evsel;
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bool use_sample_identifier = false;
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bool use_comm_exec;
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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->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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perf_evsel__config(evsel, opts, callchain);
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if (evsel->tracking && use_comm_exec)
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evsel->attr.comm_exec = 1;
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}
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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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evlist__for_each_entry(evlist, evsel)
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perf_evsel__set_sample_id(evsel, use_sample_identifier);
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} else if (evlist->nr_entries > 1) {
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struct perf_evsel *first = perf_evlist__first(evlist);
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evlist__for_each_entry(evlist, evsel) {
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if (evsel->attr.sample_type == first->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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evlist__for_each_entry(evlist, evsel)
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perf_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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pr_err("Maximum frequency rate (%u) reached.\n"
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"Please use -F freq option with 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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}
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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 perf_evlist *evlist, const char *str)
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{
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struct perf_evlist *temp_evlist;
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struct perf_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 = perf_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 = perf_evlist__last(temp_evlist);
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if (!evlist || cpu_map__empty(evlist->cpus)) {
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struct cpu_map *cpus = cpu_map__new(NULL);
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cpu = cpus ? cpus->map[0] : 0;
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cpu_map__put(cpus);
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} else {
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cpu = evlist->cpus->map[0];
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}
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while (1) {
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fd = sys_perf_event_open(&evsel->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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perf_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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