[PATCH 31/46] perf hists: Do not allocate space for callchains for evsels without them

Arnaldo Carvalho de Melo
2018-06-05T17:58:56Z

This is another case were a big switch for callchains,
symbol_conf.use_callchain, is inconvenient, as we can have both events
with and without callchains, no point in checking a single switch to
decide to allocate space for callchains.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-62q64m7x7kqpb4g7boqc2nde@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/hist.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/hist.c b/tools/perf/util/hist.c
index 34864c87cd3c..496913eeed75 100644
--- a/tools/perf/util/hist.c
+++ b/tools/perf/util/hist.c
@@ -461,14 +461,19 @@ static struct hist_entry *hist_entry__new(struct hist_entry *template,
bool sample_self)
{
struct hist_entry_ops *ops = template->ops;
+ struct perf_evsel *evsel = hists_to_evsel(template->hists);
size_t callchain_size = 0;
struct hist_entry *he;
int err = 0;

if (!ops)
ops = template->ops = &default_ops;
-
- if (symbol_conf.use_callchain)
+ /*
+ * It is possible to have callchains for some evsels but not for others,
+ * e.g.: 'perf record -e cycles,cache-misses/max-stack=10/', so lets
+ * not waste space for that.
+ */
+ if (symbol_conf.use_callchain && evsel__has_callchain(evsel))
callchain_size = sizeof(struct callchain_root);

he = ops->new(callchain_size);
--
2.14.3