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perf record: Add switch-output size warning

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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 <jolsa@kernel.org>
Suggested-and-Tested-by: Arnaldo 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: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Jiri Olsa 2017-01-09 10:51:59 +01:00 committed by Arnaldo Carvalho de Melo
parent dc0c6127c2
commit 0c5824498e
3 changed files with 24 additions and 1 deletions
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21
tools/perf/builtin-record.c
View File

@ -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;
}

2
tools/perf/util/evlist.c
View File

@ -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();

2
tools/perf/util/evlist.h
View File

@ -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);