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1// SPDX-License-Identifier: GPL-2.0-only2 3#include "util/debug.h"4#include "util/evlist.h"5#include "util/evsel.h"6#include "util/mmap.h"7#include "util/perf_api_probe.h"8#include <perf/mmap.h>9#include <linux/perf_event.h>10#include <limits.h>11#include <pthread.h>12#include <sched.h>13#include <stdbool.h>14 15int evlist__add_sb_event(struct evlist *evlist, struct perf_event_attr *attr,16 evsel__sb_cb_t cb, void *data)17{18 struct evsel *evsel;19 20 if (!attr->sample_id_all) {21 pr_warning("enabling sample_id_all for all side band events\n");22 attr->sample_id_all = 1;23 }24 25 evsel = evsel__new_idx(attr, evlist->core.nr_entries);26 if (!evsel)27 return -1;28 29 evsel->side_band.cb = cb;30 evsel->side_band.data = data;31 evlist__add(evlist, evsel);32 return 0;33}34 35static void *perf_evlist__poll_thread(void *arg)36{37 struct evlist *evlist = arg;38 bool draining = false;39 int i, done = 0;40 /*41 * In order to read symbols from other namespaces perf to needs to call42 * setns(2). This isn't permitted if the struct_fs has multiple users.43 * unshare(2) the fs so that we may continue to setns into namespaces44 * that we're observing when, for instance, reading the build-ids at45 * the end of a 'perf record' session.46 */47 unshare(CLONE_FS);48 49 while (!done) {50 bool got_data = false;51 52 if (evlist->thread.done)53 draining = true;54 55 if (!draining)56 evlist__poll(evlist, 1000);57 58 for (i = 0; i < evlist->core.nr_mmaps; i++) {59 struct mmap *map = &evlist->mmap[i];60 union perf_event *event;61 62 if (perf_mmap__read_init(&map->core))63 continue;64 while ((event = perf_mmap__read_event(&map->core)) != NULL) {65 struct evsel *evsel = evlist__event2evsel(evlist, event);66 67 if (evsel && evsel->side_band.cb)68 evsel->side_band.cb(event, evsel->side_band.data);69 else70 pr_warning("cannot locate proper evsel for the side band event\n");71 72 perf_mmap__consume(&map->core);73 got_data = true;74 }75 perf_mmap__read_done(&map->core);76 }77 78 if (draining && !got_data)79 break;80 }81 return NULL;82}83 84void evlist__set_cb(struct evlist *evlist, evsel__sb_cb_t cb, void *data)85{86 struct evsel *evsel;87 88 evlist__for_each_entry(evlist, evsel) {89 evsel->core.attr.sample_id_all = 1;90 evsel->core.attr.watermark = 1;91 evsel->core.attr.wakeup_watermark = 1;92 evsel->side_band.cb = cb;93 evsel->side_band.data = data;94 }95}96 97int evlist__start_sb_thread(struct evlist *evlist, struct target *target)98{99 struct evsel *counter;100 101 if (!evlist)102 return 0;103 104 if (evlist__create_maps(evlist, target))105 goto out_delete_evlist;106 107 if (evlist->core.nr_entries > 1) {108 bool can_sample_identifier = perf_can_sample_identifier();109 110 evlist__for_each_entry(evlist, counter)111 evsel__set_sample_id(counter, can_sample_identifier);112 113 evlist__set_id_pos(evlist);114 }115 116 evlist__for_each_entry(evlist, counter) {117 if (evsel__open(counter, evlist->core.user_requested_cpus,118 evlist->core.threads) < 0)119 goto out_delete_evlist;120 }121 122 if (evlist__mmap(evlist, UINT_MAX))123 goto out_delete_evlist;124 125 evlist__for_each_entry(evlist, counter) {126 if (evsel__enable(counter))127 goto out_delete_evlist;128 }129 130 evlist->thread.done = 0;131 if (pthread_create(&evlist->thread.th, NULL, perf_evlist__poll_thread, evlist))132 goto out_delete_evlist;133 134 return 0;135 136out_delete_evlist:137 evlist__delete(evlist);138 evlist = NULL;139 return -1;140}141 142void evlist__stop_sb_thread(struct evlist *evlist)143{144 if (!evlist)145 return;146 evlist->thread.done = 1;147 pthread_join(evlist->thread.th, NULL);148 evlist__delete(evlist);149}150