[PATCH 16/21] perf top: Remove lost events checking

From: Arnaldo Carvalho de Melo
Date: Tue Feb 06 2018 - 12:03:24 EST


From: Kan Liang <kan.liang@xxxxxxxxx>

There would be some records lost in overwrite mode because of pausing
the ringbuffer. It has little impact for the accuracy of the snapshot
and could be tolerated by 'perf top'.

Remove the lost events checking.

Signed-off-by: Kan Liang <kan.liang@xxxxxxxxx>
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Jin Yao <yao.jin@xxxxxxxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Wang Nan <wangnan0@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/1516310792-208685-16-git-send-email-kan.liang@xxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/builtin-top.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 7def861a9ec4..59653062bb48 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -283,8 +283,9 @@ static void perf_top__print_sym_table(struct perf_top *top)

printf("%-*.*s\n", win_width, win_width, graph_dotted_line);

- if (hists->stats.nr_lost_warned !=
- hists->stats.nr_events[PERF_RECORD_LOST]) {
+ if (!top->record_opts.overwrite &&
+ (hists->stats.nr_lost_warned !=
+ hists->stats.nr_events[PERF_RECORD_LOST])) {
hists->stats.nr_lost_warned =
hists->stats.nr_events[PERF_RECORD_LOST];
color_fprintf(stdout, PERF_COLOR_RED,
@@ -611,7 +612,8 @@ static void *display_thread_tui(void *arg)

perf_evlist__tui_browse_hists(top->evlist, help, &hbt,
top->min_percent,
- &top->session->header.env, true);
+ &top->session->header.env,
+ !top->record_opts.overwrite);

done = 1;
return NULL;
--
2.14.3