165 lines
3.3 KiB
C
165 lines
3.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#include "perf-sys.h"
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#include "util/cloexec.h"
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#include "util/evlist.h"
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#include "util/evsel.h"
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#include "util/parse-events.h"
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#include "util/perf_api_probe.h"
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#include <perf/cpumap.h>
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#include <errno.h>
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typedef void (*setup_probe_fn_t)(struct 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 evlist *evlist;
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struct 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 = 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 = evlist__first(evlist);
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while (1) {
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fd = sys_perf_event_open(&evsel->core.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->core.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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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 perf_cpu_map *cpus;
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int cpu, ret, i = 0;
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cpus = perf_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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perf_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 evsel *evsel)
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{
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evsel->core.attr.sample_type |= PERF_SAMPLE_IDENTIFIER;
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}
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static void perf_probe_comm_exec(struct evsel *evsel)
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{
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evsel->core.attr.comm_exec = 1;
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}
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static void perf_probe_context_switch(struct evsel *evsel)
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{
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evsel->core.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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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 perf_cpu_map *cpus;
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int cpu, fd;
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cpus = perf_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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perf_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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/*
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* Architectures are expected to know if AUX area sampling is supported by the
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* hardware. Here we check for kernel support.
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*/
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bool perf_can_aux_sample(void)
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{
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struct perf_event_attr attr = {
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.size = sizeof(struct perf_event_attr),
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.exclude_kernel = 1,
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/*
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* Non-zero value causes the kernel to calculate the effective
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* attribute size up to that byte.
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*/
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.aux_sample_size = 1,
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};
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int fd;
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fd = sys_perf_event_open(&attr, -1, 0, -1, 0);
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/*
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* If the kernel attribute is big enough to contain aux_sample_size
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* then we assume that it is supported. We are relying on the kernel to
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* validate the attribute size before anything else that could be wrong.
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*/
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if (fd < 0 && errno == E2BIG)
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return false;
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if (fd >= 0)
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close(fd);
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return true;
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}
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