perf tools: Avoid unnecessary work in directory lookups
This patch improves some (common) inefficiencies in the
handling of directory lookups:
- not using the d_type information returned by the kernel
- constructing (absolute) paths for file operation even though
directory-relative operations using the *at functions is
possible
There are more places to fix but this is a start.
Signed-off-by: Ulrich Drepper <drepper@redhat.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <20090904193951.GB6186@ghostprotocols.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 89d46c9..52219d5 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -1,14 +1,12 @@
-#include "../perf.h"
#include "util.h"
+#include "../perf.h"
#include "parse-options.h"
#include "parse-events.h"
#include "exec_cmd.h"
#include "string.h"
#include "cache.h"
-extern char *strcasestr(const char *haystack, const char *needle);
-
int nr_counters;
struct perf_counter_attr attrs[MAX_COUNTERS];
@@ -113,11 +111,9 @@
[C(BPU)] = (CACHE_READ),
};
-#define for_each_subsystem(sys_dir, sys_dirent, sys_next, file, st) \
+#define for_each_subsystem(sys_dir, sys_dirent, sys_next) \
while (!readdir_r(sys_dir, &sys_dirent, &sys_next) && sys_next) \
- if (snprintf(file, MAXPATHLEN, "%s/%s", debugfs_path, \
- sys_dirent.d_name) && \
- (!stat(file, &st)) && (S_ISDIR(st.st_mode)) && \
+ if (sys_dirent.d_type == DT_DIR && \
(strcmp(sys_dirent.d_name, ".")) && \
(strcmp(sys_dirent.d_name, "..")))
@@ -136,11 +132,9 @@
return 0;
}
-#define for_each_event(sys_dirent, evt_dir, evt_dirent, evt_next, file, st) \
+#define for_each_event(sys_dirent, evt_dir, evt_dirent, evt_next) \
while (!readdir_r(evt_dir, &evt_dirent, &evt_next) && evt_next) \
- if (snprintf(file, MAXPATHLEN, "%s/%s/%s", debugfs_path, \
- sys_dirent.d_name, evt_dirent.d_name) && \
- (!stat(file, &st)) && (S_ISDIR(st.st_mode)) && \
+ 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)))
@@ -163,9 +157,8 @@
struct tracepoint_path *path = NULL;
DIR *sys_dir, *evt_dir;
struct dirent *sys_next, *evt_next, sys_dirent, evt_dirent;
- struct stat st;
char id_buf[4];
- int fd;
+ int sys_dir_fd, fd;
u64 id;
char evt_path[MAXPATHLEN];
@@ -175,17 +168,23 @@
sys_dir = opendir(debugfs_path);
if (!sys_dir)
goto cleanup;
+ sys_dir_fd = dirfd(sys_dir);
- for_each_subsystem(sys_dir, sys_dirent, sys_next, evt_path, st) {
- evt_dir = opendir(evt_path);
- if (!evt_dir)
- goto cleanup;
- for_each_event(sys_dirent, evt_dir, evt_dirent, evt_next,
- evt_path, st) {
- snprintf(evt_path, MAXPATHLEN, "%s/%s/%s/id",
- debugfs_path, sys_dirent.d_name,
+ for_each_subsystem(sys_dir, sys_dirent, sys_next) {
+ int dfd = openat(sys_dir_fd, sys_dirent.d_name,
+ O_RDONLY|O_DIRECTORY), evt_dir_fd;
+ if (dfd == -1)
+ continue;
+ evt_dir = fdopendir(dfd);
+ if (!evt_dir) {
+ close(dfd);
+ continue;
+ }
+ evt_dir_fd = dirfd(evt_dir);
+ for_each_event(sys_dirent, evt_dir, evt_dirent, evt_next) {
+ snprintf(evt_path, MAXPATHLEN, "%s/id",
evt_dirent.d_name);
- fd = open(evt_path, O_RDONLY);
+ fd = openat(evt_dir_fd, evt_path, O_RDONLY);
if (fd < 0)
continue;
if (read(fd, id_buf, sizeof(id_buf)) < 0) {
@@ -629,7 +628,7 @@
{
DIR *sys_dir, *evt_dir;
struct dirent *sys_next, *evt_next, sys_dirent, evt_dirent;
- struct stat st;
+ int sys_dir_fd;
char evt_path[MAXPATHLEN];
if (valid_debugfs_mount(debugfs_path))
@@ -638,13 +637,20 @@
sys_dir = opendir(debugfs_path);
if (!sys_dir)
goto cleanup;
+ sys_dir_fd = dirfd(sys_dir);
- for_each_subsystem(sys_dir, sys_dirent, sys_next, evt_path, st) {
- evt_dir = opendir(evt_path);
- if (!evt_dir)
- goto cleanup;
- for_each_event(sys_dirent, evt_dir, evt_dirent, evt_next,
- evt_path, st) {
+ for_each_subsystem(sys_dir, sys_dirent, sys_next) {
+ int dfd = openat(sys_dir_fd, sys_dirent.d_name,
+ O_RDONLY|O_DIRECTORY), evt_dir_fd;
+ if (dfd == -1)
+ continue;
+ evt_dir = fdopendir(dfd);
+ if (!evt_dir) {
+ close(dfd);
+ continue;
+ }
+ evt_dir_fd = dirfd(evt_dir);
+ for_each_event(sys_dirent, evt_dir, evt_dirent, evt_next) {
snprintf(evt_path, MAXPATHLEN, "%s:%s",
sys_dirent.d_name, evt_dirent.d_name);
fprintf(stderr, " %-40s [%s]\n", evt_path,