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976be84504
I.e. so far we had just one event in that side band thread, a dummy one with attr.bpf_event set, so that 'perf record' can go ahead and ask the kernel for further information about BPF programs being loaded. Allow for more than one event to be there, so that we can use it as well for the upcoming --switch-output-event feature. Acked-by: Jiri Olsa <jolsa@redhat.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Song Liu <songliubraving@fb.com> Link: http://lore.kernel.org/lkml/20200429131106.27974-6-acme@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
149 lines
3.5 KiB
C
149 lines
3.5 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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#include "util/debug.h"
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#include "util/evlist.h"
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#include "util/evsel.h"
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#include "util/mmap.h"
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#include "util/perf_api_probe.h"
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#include <perf/mmap.h>
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#include <linux/perf_event.h>
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#include <limits.h>
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#include <pthread.h>
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#include <sched.h>
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#include <stdbool.h>
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int perf_evlist__add_sb_event(struct evlist *evlist, struct perf_event_attr *attr,
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perf_evsel__sb_cb_t cb, void *data)
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{
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struct evsel *evsel;
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if (!attr->sample_id_all) {
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pr_warning("enabling sample_id_all for all side band events\n");
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attr->sample_id_all = 1;
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}
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evsel = perf_evsel__new_idx(attr, evlist->core.nr_entries);
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if (!evsel)
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return -1;
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evsel->side_band.cb = cb;
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evsel->side_band.data = data;
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evlist__add(evlist, evsel);
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return 0;
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}
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static void *perf_evlist__poll_thread(void *arg)
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{
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struct evlist *evlist = arg;
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bool draining = false;
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int i, done = 0;
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/*
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* In order to read symbols from other namespaces perf to needs to call
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* setns(2). This isn't permitted if the struct_fs has multiple users.
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* unshare(2) the fs so that we may continue to setns into namespaces
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* that we're observing when, for instance, reading the build-ids at
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* the end of a 'perf record' session.
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*/
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unshare(CLONE_FS);
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while (!done) {
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bool got_data = false;
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if (evlist->thread.done)
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draining = true;
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if (!draining)
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evlist__poll(evlist, 1000);
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for (i = 0; i < evlist->core.nr_mmaps; i++) {
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struct mmap *map = &evlist->mmap[i];
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union perf_event *event;
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if (perf_mmap__read_init(&map->core))
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continue;
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while ((event = perf_mmap__read_event(&map->core)) != NULL) {
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struct evsel *evsel = perf_evlist__event2evsel(evlist, event);
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if (evsel && evsel->side_band.cb)
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evsel->side_band.cb(event, evsel->side_band.data);
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else
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pr_warning("cannot locate proper evsel for the side band event\n");
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perf_mmap__consume(&map->core);
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got_data = true;
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}
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perf_mmap__read_done(&map->core);
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}
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if (draining && !got_data)
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break;
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}
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return NULL;
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}
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void evlist__set_cb(struct evlist *evlist, perf_evsel__sb_cb_t cb, void *data)
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{
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struct evsel *evsel;
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evlist__for_each_entry(evlist, evsel) {
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evsel->core.attr.sample_id_all = 1;
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evsel->core.attr.watermark = 1;
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evsel->core.attr.wakeup_watermark = 1;
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evsel->side_band.cb = cb;
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evsel->side_band.data = data;
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}
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}
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int perf_evlist__start_sb_thread(struct evlist *evlist, struct target *target)
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{
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struct evsel *counter;
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if (!evlist)
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return 0;
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if (perf_evlist__create_maps(evlist, target))
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goto out_delete_evlist;
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if (evlist->core.nr_entries > 1) {
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bool can_sample_identifier = perf_can_sample_identifier();
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evlist__for_each_entry(evlist, counter)
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perf_evsel__set_sample_id(counter, can_sample_identifier);
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perf_evlist__set_id_pos(evlist);
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}
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evlist__for_each_entry(evlist, counter) {
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if (evsel__open(counter, evlist->core.cpus, evlist->core.threads) < 0)
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goto out_delete_evlist;
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}
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if (evlist__mmap(evlist, UINT_MAX))
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goto out_delete_evlist;
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evlist__for_each_entry(evlist, counter) {
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if (evsel__enable(counter))
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goto out_delete_evlist;
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}
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evlist->thread.done = 0;
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if (pthread_create(&evlist->thread.th, NULL, perf_evlist__poll_thread, evlist))
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goto out_delete_evlist;
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return 0;
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out_delete_evlist:
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evlist__delete(evlist);
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evlist = NULL;
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return -1;
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}
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void perf_evlist__stop_sb_thread(struct evlist *evlist)
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{
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if (!evlist)
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return;
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evlist->thread.done = 1;
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pthread_join(evlist->thread.th, NULL);
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evlist__delete(evlist);
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}
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