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-rw-r--r--tools/perf/util/sideband_evlist.c148
1 files changed, 148 insertions, 0 deletions
diff --git a/tools/perf/util/sideband_evlist.c b/tools/perf/util/sideband_evlist.c
new file mode 100644
index 000000000..ded9ced02
--- /dev/null
+++ b/tools/perf/util/sideband_evlist.c
@@ -0,0 +1,148 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include "util/debug.h"
+#include "util/evlist.h"
+#include "util/evsel.h"
+#include "util/mmap.h"
+#include "util/perf_api_probe.h"
+#include <perf/mmap.h>
+#include <linux/perf_event.h>
+#include <limits.h>
+#include <pthread.h>
+#include <sched.h>
+#include <stdbool.h>
+
+int perf_evlist__add_sb_event(struct evlist *evlist, struct perf_event_attr *attr,
+ evsel__sb_cb_t cb, void *data)
+{
+ struct evsel *evsel;
+
+ if (!attr->sample_id_all) {
+ pr_warning("enabling sample_id_all for all side band events\n");
+ attr->sample_id_all = 1;
+ }
+
+ evsel = evsel__new_idx(attr, evlist->core.nr_entries);
+ if (!evsel)
+ return -1;
+
+ evsel->side_band.cb = cb;
+ evsel->side_band.data = data;
+ evlist__add(evlist, evsel);
+ return 0;
+}
+
+static void *perf_evlist__poll_thread(void *arg)
+{
+ struct evlist *evlist = arg;
+ bool draining = false;
+ int i, done = 0;
+ /*
+ * In order to read symbols from other namespaces perf to needs to call
+ * setns(2). This isn't permitted if the struct_fs has multiple users.
+ * unshare(2) the fs so that we may continue to setns into namespaces
+ * that we're observing when, for instance, reading the build-ids at
+ * the end of a 'perf record' session.
+ */
+ unshare(CLONE_FS);
+
+ while (!done) {
+ bool got_data = false;
+
+ if (evlist->thread.done)
+ draining = true;
+
+ if (!draining)
+ evlist__poll(evlist, 1000);
+
+ for (i = 0; i < evlist->core.nr_mmaps; i++) {
+ struct mmap *map = &evlist->mmap[i];
+ union perf_event *event;
+
+ if (perf_mmap__read_init(&map->core))
+ continue;
+ while ((event = perf_mmap__read_event(&map->core)) != NULL) {
+ struct evsel *evsel = perf_evlist__event2evsel(evlist, event);
+
+ if (evsel && evsel->side_band.cb)
+ evsel->side_band.cb(event, evsel->side_band.data);
+ else
+ pr_warning("cannot locate proper evsel for the side band event\n");
+
+ perf_mmap__consume(&map->core);
+ got_data = true;
+ }
+ perf_mmap__read_done(&map->core);
+ }
+
+ if (draining && !got_data)
+ break;
+ }
+ return NULL;
+}
+
+void evlist__set_cb(struct evlist *evlist, evsel__sb_cb_t cb, void *data)
+{
+ struct evsel *evsel;
+
+ evlist__for_each_entry(evlist, evsel) {
+ evsel->core.attr.sample_id_all = 1;
+ evsel->core.attr.watermark = 1;
+ evsel->core.attr.wakeup_watermark = 1;
+ evsel->side_band.cb = cb;
+ evsel->side_band.data = data;
+ }
+}
+
+int perf_evlist__start_sb_thread(struct evlist *evlist, struct target *target)
+{
+ struct evsel *counter;
+
+ if (!evlist)
+ return 0;
+
+ if (perf_evlist__create_maps(evlist, target))
+ goto out_delete_evlist;
+
+ if (evlist->core.nr_entries > 1) {
+ bool can_sample_identifier = perf_can_sample_identifier();
+
+ evlist__for_each_entry(evlist, counter)
+ evsel__set_sample_id(counter, can_sample_identifier);
+
+ perf_evlist__set_id_pos(evlist);
+ }
+
+ evlist__for_each_entry(evlist, counter) {
+ if (evsel__open(counter, evlist->core.cpus, evlist->core.threads) < 0)
+ goto out_delete_evlist;
+ }
+
+ if (evlist__mmap(evlist, UINT_MAX))
+ goto out_delete_evlist;
+
+ evlist__for_each_entry(evlist, counter) {
+ if (evsel__enable(counter))
+ goto out_delete_evlist;
+ }
+
+ evlist->thread.done = 0;
+ if (pthread_create(&evlist->thread.th, NULL, perf_evlist__poll_thread, evlist))
+ goto out_delete_evlist;
+
+ return 0;
+
+out_delete_evlist:
+ evlist__delete(evlist);
+ evlist = NULL;
+ return -1;
+}
+
+void perf_evlist__stop_sb_thread(struct evlist *evlist)
+{
+ if (!evlist)
+ return;
+ evlist->thread.done = 1;
+ pthread_join(evlist->thread.th, NULL);
+ evlist__delete(evlist);
+}