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: Nilay Vaish <nilayva...@gmail.com> Cc: pi3or...@163.com --- tools/perf/builtin-record.c | 59 ++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 56 insertions(+), 3 deletions(-) diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index b2b3b60..3b62295 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -51,6 +51,7 @@ 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; @@ -342,13 +343,41 @@ 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_entry(evlist, pos) { + if (!pos->attr.write_backward) + 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) + struct perf_evlist *evlist, + bool overwrite) { struct record_opts *opts = &rec->opts; char msg[512]; - if (perf_evlist__mmap_ex(evlist, opts->mmap_pages, false, + /* + * 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) { @@ -373,7 +402,23 @@ static int record__mmap_evlist(struct record *rec, static int record__mmap(struct record *rec) { - return record__mmap_evlist(rec, rec->evlist); + 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) @@ -698,9 +743,14 @@ static const struct perf_event_mmap_page *record__pick_pc(struct record *rec) { 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; } @@ -1311,6 +1361,7 @@ static struct record record = { .mmap2 = perf_event__process_mmap2, .ordered_events = true, }, + .overwrite_evlist = NULL, }; const char record_callchain_help[] = CALLCHAIN_RECORD_HELP @@ -1614,6 +1665,8 @@ 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