From f06149c0db430d3694d601df126b0944cc0156a6 Mon Sep 17 00:00:00 2001 From: Wang Nan Date: Thu, 14 Jul 2016 08:34:46 +0000 Subject: [PATCH] perf session: Don't warn about out of order event if write_backward is used If write_backward attribute is set, records are written into kernel ring buffer from end to beginning, but read from beginning to end. To avoid 'XX out of order events recorded' warning message (timestamps of records is in reverse order when using write_backward), suppress the warning message if write_backward is selected by at lease one event. Result: Before this patch: # perf record -m 1 -e raw_syscalls:sys_exit/overwrite/ \ -e raw_syscalls:sys_enter \ dd if=/dev/zero of=/dev/null count=300 300+0 records in 300+0 records out 153600 bytes (154 kB) copied, 0.000601617 s, 255 MB/s [ perf record: Woken up 5 times to write data ] Warning: 40 out of order events recorded. [ perf record: Captured and wrote 0.096 MB perf.data (696 samples) ] After this patch: # perf record -m 1 -e raw_syscalls:sys_exit/overwrite/ \ -e raw_syscalls:sys_enter \ dd if=/dev/zero of=/dev/null count=300 300+0 records in 300+0 records out 153600 bytes (154 kB) copied, 0.000644873 s, 238 MB/s [ perf record: Woken up 5 times to write data ] [ perf record: Captured and wrote 0.096 MB perf.data (696 samples) ] Signed-off-by: Wang Nan Acked-by: Jiri Olsa Tested-by: Arnaldo Carvalho de Melo Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Nilay Vaish Cc: Zefan Li Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1468485287-33422-15-git-send-email-wangnan0@huawei.com Signed-off-by: He Kuang Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/session.c | 22 +++++++++++++++++++--- 1 file changed, 19 insertions(+), 3 deletions(-) diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c index 078d49626494..5d61242a6e64 100644 --- a/tools/perf/util/session.c +++ b/tools/perf/util/session.c @@ -1499,10 +1499,27 @@ int perf_session__register_idle_thread(struct perf_session *session) return err; } +static void +perf_session__warn_order(const struct perf_session *session) +{ + const struct ordered_events *oe = &session->ordered_events; + struct perf_evsel *evsel; + bool should_warn = true; + + evlist__for_each_entry(session->evlist, evsel) { + if (evsel->attr.write_backward) + should_warn = false; + } + + if (!should_warn) + return; + if (oe->nr_unordered_events != 0) + ui__warning("%u out of order events recorded.\n", oe->nr_unordered_events); +} + static void perf_session__warn_about_errors(const struct perf_session *session) { const struct events_stats *stats = &session->evlist->stats; - const struct ordered_events *oe = &session->ordered_events; if (session->tool->lost == perf_event__process_lost && stats->nr_events[PERF_RECORD_LOST] != 0) { @@ -1559,8 +1576,7 @@ static void perf_session__warn_about_errors(const struct perf_session *session) stats->nr_unprocessable_samples); } - if (oe->nr_unordered_events != 0) - ui__warning("%u out of order events recorded.\n", oe->nr_unordered_events); + perf_session__warn_order(session); events_stats__auxtrace_error_warn(stats); -- 2.20.1