Create a 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 <masami.hiramatsu...@hitachi.com> Cc: Namhyung Kim <namhy...@kernel.org> Cc: Zefan Li <lize...@huawei.com> Cc: pi3or...@163.com --- tools/perf/builtin-record.c | 125 ++++++++++++++++++++++++++++++++++++-------- 1 file changed, 102 insertions(+), 23 deletions(-) diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index 9611380..b940c0d 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 +342,78 @@ 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) +{ + struct record_opts *opts = &rec->opts; + char msg[512]; + + if (perf_evlist__mmap_ex(evlist, opts->mmap_pages, evlist->backward, + 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); + if (err) + return err; + + if (!rec->overwrite_evlist) + return 0; + + err = record__mmap_evlist(rec, rec->overwrite_evlist); + if (err) + return err; + return 0; +} + static int record__open(struct record *rec) { char msg[512]; @@ -353,6 +426,13 @@ 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 +457,9 @@ 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 +716,26 @@ 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; } @@ -1566,6 +1643,8 @@ 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