Commit 0c582449 authored by Jiri Olsa's avatar Jiri Olsa Committed by Arnaldo Carvalho de Melo
Browse files

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: default avatarJiri Olsa <jolsa@kernel.org>
Suggested-and-Tested-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1483955520-29063-6-git-send-email-jolsa@kernel.org


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent dc0c6127

tools/perf/builtin-record.c

+21 −0
Original line number Diff line number Diff line
@@ -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;

}

tools/perf/util/evlist.c

+1 −1
Original line number Diff line number Diff line
@@ -1184,7 +1184,7 @@ unsigned long perf_event_mlock_kb_in_pages(void) 
	return pages;

}



static size_t perf_evlist__mmap_size(unsigned long pages)

size_t perf_evlist__mmap_size(unsigned long pages)

{

	if (pages == UINT_MAX)

		pages = perf_event_mlock_kb_in_pages();

tools/perf/util/evlist.h

+2 −0
Original line number Diff line number Diff line
@@ -218,6 +218,8 @@ int perf_evlist__mmap(struct perf_evlist *evlist, unsigned int pages, 
		      bool overwrite);

void perf_evlist__munmap(struct perf_evlist *evlist);



size_t perf_evlist__mmap_size(unsigned long pages);



void perf_evlist__disable(struct perf_evlist *evlist);

void perf_evlist__enable(struct perf_evlist *evlist);

void perf_evlist__toggle_enable(struct perf_evlist *evlist);

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