Create an auxiliary evlist for overwritable events.
Before mmap, build this evlist and set 'overwrite' and 'backward'
attribute. Since perf_evlist__mmap_ex() only maps events when
evsel->overwrite matches evlist's corresponding attributes, with
these two evlists an event goes to either rec->evlist or
rec->overwrite_evlist.
Signed-off-by: Wang Nan <wangn...@huawei.com>
Cc: He Kuang <heku...@huawei.com>
Cc: Arnaldo Carvalho de Melo <a...@redhat.com>
Cc: Jiri Olsa <jo...@kernel.org>
Cc: Masami Hiramatsu <mhira...@kernel.org>
Cc: Namhyung Kim <namhy...@kernel.org>
Cc: Zefan Li <lize...@huawei.com>
Cc: pi3or...@163.com
---
tools/perf/builtin-record.c | 140 ++++++++++++++++++++++++++++++++++++--------
1 file changed, 117 insertions(+), 23 deletions(-)
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index d4cf1b0..8108332 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -50,6 +50,7 @@ struct record {
struct perf_data_file file;
struct auxtrace_record *itr;
struct perf_evlist *evlist;
+ struct perf_evlist *overwrite_evlist;
struct perf_session *session;
const char *progname;
int realtime_prio;
@@ -341,6 +342,84 @@ int auxtrace_record__snapshot_start(struct auxtrace_record
*itr __maybe_unused)
#endif
+static int record__create_overwrite_evlist(struct record *rec)
+{
+ struct perf_evlist *evlist = rec->evlist;
+ struct perf_evsel *pos;
+
+ evlist__for_each(evlist, pos) {
+ if (!pos->overwrite)
+ continue;
+
+ if (!rec->overwrite_evlist) {
+ rec->overwrite_evlist = perf_evlist__new_aux(evlist);
+ if (rec->overwrite_evlist) {
+ rec->overwrite_evlist->backward = true;
+ rec->overwrite_evlist->overwrite = true;
+ return 0;
+ } else
+ return -ENOMEM;
+ }
+ }
+ return 0;
+}
+
+static int record__mmap_evlist(struct record *rec,
+ struct perf_evlist *evlist,
+ bool overwrite)
+{
+ struct record_opts *opts = &rec->opts;
+ char msg[512];
+
+ /*
+ * Don't use evlist->overwrite because it is logically an
+ * internal attribute and is set by perf_evlist__mmap_ex().
+ * Avoid circular dependency.
+ */
+ if (perf_evlist__mmap_ex(evlist, opts->mmap_pages, overwrite,
+ opts->auxtrace_mmap_pages,
+ opts->auxtrace_snapshot_mode) < 0) {
+ if (errno == EPERM) {
+ pr_err("Permission error mapping pages.\n"
+ "Consider increasing "
+ "/proc/sys/kernel/perf_event_mlock_kb,\n"
+ "or try again with a smaller value of
-m/--mmap_pages.\n"
+ "(current value: %u,%u)\n",
+ opts->mmap_pages, opts->auxtrace_mmap_pages);
+ return -errno;
+ } else {
+ pr_err("failed to mmap with %d (%s)\n", errno,
+ strerror_r(errno, msg, sizeof(msg)));
+ if (errno)
+ return -errno;
+ else
+ return -EINVAL;
+ }
+ }
+ return 0;
+}
+
+static int record__mmap(struct record *rec)
+{
+ int err;
+
+ err = record__create_overwrite_evlist(rec);
+ if (err)
+ return err;
+
+ err = record__mmap_evlist(rec, rec->evlist, false);
+ if (err)
+ return err;
+
+ if (!rec->overwrite_evlist)
+ return 0;
+
+ err = record__mmap_evlist(rec, rec->overwrite_evlist, true);
+ if (err)
+ return err;
+ return 0;
+}
+
static int record__open(struct record *rec)
{
char msg[512];
@@ -353,6 +432,13 @@ static int record__open(struct record *rec)
perf_evlist__config(evlist, opts, &callchain_param);
evlist__for_each(evlist, pos) {
+ if (pos->overwrite) {
+ if (!pos->attr.write_backward) {
+ ui__warning("Unable to read from overwrite ring
buffer\n\n");
+ rc = -ENOSYS;
+ goto out;
+ }
+ }
try_again:
if (perf_evsel__open(pos, pos->cpus, pos->threads) < 0) {
if (perf_evsel__fallback(pos, errno, msg, sizeof(msg)))
{
@@ -377,28 +463,9 @@ try_again:
goto out;
}
- if (perf_evlist__mmap_ex(evlist, opts->mmap_pages, false,
- opts->auxtrace_mmap_pages,
- opts->auxtrace_snapshot_mode) < 0) {
- if (errno == EPERM) {
- pr_err("Permission error mapping pages.\n"
- "Consider increasing "
- "/proc/sys/kernel/perf_event_mlock_kb,\n"
- "or try again with a smaller value of
-m/--mmap_pages.\n"
- "(current value: %u,%u)\n",
- opts->mmap_pages, opts->auxtrace_mmap_pages);
- rc = -errno;
- } else {
- pr_err("failed to mmap with %d (%s)\n", errno,
- strerror_r(errno, msg, sizeof(msg)));
- if (errno)
- rc = -errno;
- else
- rc = -EINVAL;
- }
+ rc = record__mmap(rec);
+ if (rc)
goto out;
- }
-
session->evlist = evlist;
perf_session__set_id_hdr_size(session);
out:
@@ -655,10 +722,26 @@ perf_event__synth_time_conv(const struct
perf_event_mmap_page *pc __maybe_unused
return 0;
}
+static const struct perf_event_mmap_page *
+perf_evlist__pick_pc(struct perf_evlist *evlist)
+{
+ if (evlist && evlist->mmap && evlist->mmap[0].base)
+ return evlist->mmap[0].base;
+ return NULL;
+}
+
static const struct perf_event_mmap_page *record__pick_pc(struct record *rec)
{
- if (rec->evlist && rec->evlist->mmap && rec->evlist->mmap[0].base)
- return rec->evlist->mmap[0].base;
+ const struct perf_event_mmap_page *pc;
+
+ /* Change it to a loop if a new aux evlist is added */
+ pc = perf_evlist__pick_pc(rec->evlist);
+ if (pc)
+ return pc;
+ pc = perf_evlist__pick_pc(rec->overwrite_evlist);
+ if (pc)
+ return pc;
+
return NULL;
}
@@ -941,6 +1024,14 @@ static int __cmd_record(struct record *rec, int argc,
const char **argv)
err = 0;
waking++;
+ /*
+ * Although we may have auxiliray evlist, there is
+ * only one pollfd, so we don't need to filter pollfd
+ * for auxiliray evlist.
+ *
+ * TODO: if an event is terminated (POLLERR | POLLHUP),
+ * unmap mmaps for auxiliray evlist too.
+ */
if (perf_evlist__filter_pollfd(rec->evlist, POLLERR |
POLLHUP) == 0)
draining = true;
}
@@ -1269,6 +1360,7 @@ static struct record record = {
.mmap2 = perf_event__process_mmap2,
.ordered_events = true,
},
+ .overwrite_evlist = NULL,
};
const char record_callchain_help[] = CALLCHAIN_RECORD_HELP
@@ -1565,6 +1657,8 @@ int cmd_record(int argc, const char **argv, const char
*prefix __maybe_unused)
err = __cmd_record(&record, argc, argv);
out_symbol_exit:
perf_evlist__delete(rec->evlist);
+ if (rec->overwrite_evlist)
+ perf_evlist__delete(rec->overwrite_evlist);
symbol__exit();
auxtrace_record__free(rec->itr);
return err;
--
1.8.3.4
