[tip:perf/core] perf tools: Reuse the path to the tracepoint /events/ directory

From: tip-bot for Arnaldo Carvalho de Melo
Date: Sat May 19 2018 - 06:46:12 EST


Commit-ID: c02cab228e44aacf161642b63779971f8e39993b
Gitweb: https://git.kernel.org/tip/c02cab228e44aacf161642b63779971f8e39993b
Author: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
AuthorDate: Thu, 17 May 2018 14:22:37 -0300
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Thu, 17 May 2018 14:25:07 -0300

perf tools: Reuse the path to the tracepoint /events/ directory

When using for_each_event() we needlessly rebuild the whole path to
the tracepoint directory, reuse the dir_path instead, saving some cycles
and reducing the size of the next patch.

Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Wang Nan <wangnan0@xxxxxxxxxx>
Link: https://lkml.kernel.org/n/tip-54bcs15n0cp6gwcgpc4hptyc@xxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/util/parse-events.c | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 2fc4ee8b86c1..f9d5bbd63484 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -156,13 +156,12 @@ struct event_symbol event_symbols_sw[PERF_COUNT_SW_MAX] = {
(strcmp(sys_dirent->d_name, ".")) && \
(strcmp(sys_dirent->d_name, "..")))

-static int tp_event_has_id(struct dirent *sys_dir, struct dirent *evt_dir)
+static int tp_event_has_id(const char *dir_path, struct dirent *evt_dir)
{
char evt_path[MAXPATHLEN];
int fd;

- snprintf(evt_path, MAXPATHLEN, "%s/%s/%s/id", tracing_events_path,
- sys_dir->d_name, evt_dir->d_name);
+ snprintf(evt_path, MAXPATHLEN, "%s/%s/id", dir_path, evt_dir->d_name);
fd = open(evt_path, O_RDONLY);
if (fd < 0)
return -EINVAL;
@@ -171,12 +170,12 @@ static int tp_event_has_id(struct dirent *sys_dir, struct dirent *evt_dir)
return 0;
}

-#define for_each_event(sys_dirent, evt_dir, evt_dirent) \
+#define for_each_event(dir_path, evt_dir, evt_dirent) \
while ((evt_dirent = readdir(evt_dir)) != NULL) \
if (evt_dirent->d_type == DT_DIR && \
(strcmp(evt_dirent->d_name, ".")) && \
(strcmp(evt_dirent->d_name, "..")) && \
- (!tp_event_has_id(sys_dirent, evt_dirent)))
+ (!tp_event_has_id(dir_path, evt_dirent)))

#define MAX_EVENT_LENGTH 512

@@ -204,7 +203,7 @@ struct tracepoint_path *tracepoint_id_to_path(u64 config)
if (!evt_dir)
continue;

- for_each_event(sys_dirent, evt_dir, evt_dirent) {
+ for_each_event(dir_path, evt_dir, evt_dirent) {

scnprintf(evt_path, MAXPATHLEN, "%s/%s/id", dir_path,
evt_dirent->d_name);
@@ -2119,7 +2118,7 @@ restart:
if (!evt_dir)
continue;

- for_each_event(sys_dirent, evt_dir, evt_dirent) {
+ for_each_event(dir_path, evt_dir, evt_dirent) {
if (event_glob != NULL &&
!strglobmatch(evt_dirent->d_name, event_glob))
continue;
@@ -2199,7 +2198,7 @@ int is_valid_tracepoint(const char *event_string)
if (!evt_dir)
continue;

- for_each_event(sys_dirent, evt_dir, evt_dirent) {
+ for_each_event(dir_path, evt_dir, evt_dirent) {
snprintf(evt_path, MAXPATHLEN, "%s:%s",
sys_dirent->d_name, evt_dirent->d_name);
if (!strcmp(evt_path, event_string)) {