From 0c5824498e8bd5b7d30dc03448cd89efaee4bead Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Mon, 9 Jan 2017 10:51:59 +0100 Subject: perf record: Add switch-output size warning Adding switch-output size warning if the requested size of lower than the wakeup ring buffer size. $ perf record --switch-output=1K ls WARNING: switch-output data size lower than wakeup kernel buffer size (258K) expect bigger perf.data sizes ... Signed-off-by: Jiri Olsa Suggested-and-Tested-by: Arnaldo Carvalho de Melo Cc: David Ahern Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Wang Nan Link: http://lkml.kernel.org/r/1483955520-29063-6-git-send-email-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-record.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) (limited to 'tools/perf/builtin-record.c') diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index 3fa64492ee62..93319e1be3ac 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -1377,6 +1377,23 @@ out_free: return ret; } +static void switch_output_size_warn(struct record *rec) +{ + u64 wakeup_size = perf_evlist__mmap_size(rec->opts.mmap_pages); + struct switch_output *s = &rec->switch_output; + + wakeup_size /= 2; + + if (s->size < wakeup_size) { + char buf[100]; + + unit_number__scnprintf(buf, sizeof(buf), wakeup_size); + pr_warning("WARNING: switch-output data size lower than " + "wakeup kernel buffer size (%s) " + "expect bigger perf.data sizes\n", buf); + } +} + static int switch_output_setup(struct record *rec) { struct switch_output *s = &rec->switch_output; @@ -1410,6 +1427,10 @@ static int switch_output_setup(struct record *rec) enabled: rec->timestamp_filename = true; s->enabled = true; + + if (s->size && !rec->opts.no_buffering) + switch_output_size_warn(rec); + return 0; } -- cgit v1.2.3-59-g8ed1b