From: Ian Rogers <irogers@google.com>
To: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Namhyung Kim <namhyung@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@kernel.org>, Ian Rogers <irogers@google.com>,
Adrian Hunter <adrian.hunter@intel.com>,
Kan Liang <kan.liang@linux.intel.com>,
linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v2] perf tracepoint: Don't scan all tracepoints to test if one exists
Date: Thu, 9 May 2024 08:32:45 -0700 [thread overview]
Message-ID: <20240509153245.1990426-1-irogers@google.com> (raw)
In is_valid_tracepoint, rather than scanning
"/sys/kernel/tracing/events/*/*" skipping any path where
"/sys/kernel/tracing/events/*/*/id" doesn't exist, and then testing if
"*:*" matches the tracepoint name, just use the given tracepoint name
replace the ':' with '/' and see if the id file exists. This turns a
nested directory search into a single file available test.
Rather than return 1 for valid and 0 for invalid, return true and
false.
Signed-off-by: Ian Rogers <irogers@google.com>
---
v2. Fix potential uninitialized use on memory allocation failure path.
---
tools/perf/util/tracepoint.c | 56 ++++++++++++++----------------------
tools/perf/util/tracepoint.h | 3 +-
2 files changed, 24 insertions(+), 35 deletions(-)
diff --git a/tools/perf/util/tracepoint.c b/tools/perf/util/tracepoint.c
index 92dd8b455b90..bb06d10fbe37 100644
--- a/tools/perf/util/tracepoint.c
+++ b/tools/perf/util/tracepoint.c
@@ -4,10 +4,12 @@
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
+#include <stdlib.h>
#include <sys/param.h>
#include <unistd.h>
#include <api/fs/tracing_path.h>
+#include "fncache.h"
int tp_event_has_id(const char *dir_path, struct dirent *evt_dir)
{
@@ -26,39 +28,25 @@ int tp_event_has_id(const char *dir_path, struct dirent *evt_dir)
/*
* Check whether event is in <debugfs_mount_point>/tracing/events
*/
-int is_valid_tracepoint(const char *event_string)
+bool is_valid_tracepoint(const char *event_string)
{
- DIR *sys_dir, *evt_dir;
- struct dirent *sys_dirent, *evt_dirent;
- char evt_path[MAXPATHLEN];
- char *dir_path;
-
- sys_dir = tracing_events__opendir();
- if (!sys_dir)
- return 0;
-
- for_each_subsystem(sys_dir, sys_dirent) {
- dir_path = get_events_file(sys_dirent->d_name);
- if (!dir_path)
- continue;
- evt_dir = opendir(dir_path);
- if (!evt_dir)
- goto next;
-
- 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)) {
- closedir(evt_dir);
- put_events_file(dir_path);
- closedir(sys_dir);
- return 1;
- }
- }
- closedir(evt_dir);
-next:
- put_events_file(dir_path);
- }
- closedir(sys_dir);
- return 0;
+ char *dst, *path = malloc(strlen(event_string) + 4); /* Space for "/id\0". */
+ const char *src;
+ bool have_file = false; /* Conservatively return false if memory allocation failed. */
+
+ if (!path)
+ return false;
+
+ /* Copy event_string replacing the ':' with '/'. */
+ for (src = event_string, dst = path; *src; src++, dst++)
+ *dst = (*src == ':') ? '/' : *src;
+ /* Add "/id\0". */
+ memcpy(dst, "/id", 4);
+
+ dst = get_events_file(path);
+ if (dst)
+ have_file = file_available(dst);
+ free(dst);
+ free(path);
+ return have_file;
}
diff --git a/tools/perf/util/tracepoint.h b/tools/perf/util/tracepoint.h
index c4a110fe87d7..65ccb01fc312 100644
--- a/tools/perf/util/tracepoint.h
+++ b/tools/perf/util/tracepoint.h
@@ -4,6 +4,7 @@
#include <dirent.h>
#include <string.h>
+#include <stdbool.h>
int tp_event_has_id(const char *dir_path, struct dirent *evt_dir);
@@ -20,6 +21,6 @@ int tp_event_has_id(const char *dir_path, struct dirent *evt_dir);
(strcmp(sys_dirent->d_name, ".")) && \
(strcmp(sys_dirent->d_name, "..")))
-int is_valid_tracepoint(const char *event_string);
+bool is_valid_tracepoint(const char *event_string);
#endif /* __PERF_TRACEPOINT_H */
--
2.45.0.rc1.225.g2a3ae87e7f-goog
next reply other threads:[~2024-05-09 15:32 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-09 15:32 Ian Rogers [this message]
2024-05-09 21:43 ` [PATCH v2] perf tracepoint: Don't scan all tracepoints to test if one exists Arnaldo Carvalho de Melo
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