[PATCH v1 3/9] perf tracepoint: Sort events in iterator

Ian Rogers
2022-11-14T07:52:30Z

In print_tracepoint_events use tracing_events__scandir_alphasort and
scandir alphasort so that the subsystem and events are sorted and
don't need a secondary qsort. Locally this results in the following
change:

...
ext4:ext4_zero_range [Tracepoint event]
- fib6:fib6_table_lookup [Tracepoint event]
fib:fib_table_lookup [Tracepoint event]
+ fib6:fib6_table_lookup [Tracepoint event]
filelock:break_lease_block [Tracepoint event]
...

ie fib6 now is after fib and not before it. This is more consistent
with how numbers are more generally sorted, such as:

...
syscalls:sys_enter_renameat [Tracepoint event]
syscalls:sys_enter_renameat2 [Tracepoint event]
...

and so an improvement over the qsort approach.

Signed-off-by: Ian Rogers <irogers@google.com>
---
tools/perf/util/print-events.c | 108 +++++++++++----------------------
1 file changed, 37 insertions(+), 71 deletions(-)

diff --git a/tools/perf/util/print-events.c b/tools/perf/util/print-events.c
index c4d5d87fae2f..fefc025bc259 100644
--- a/tools/perf/util/print-events.c
+++ b/tools/perf/util/print-events.c
@@ -66,26 +66,21 @@ static int cmp_string(const void *a, const void *b)
void print_tracepoint_events(const char *subsys_glob,
const char *event_glob, bool name_only)
{
- DIR *sys_dir, *evt_dir;
- struct dirent *sys_dirent, *evt_dirent;
- char evt_path[MAXPATHLEN];
- char *dir_path;
- char **evt_list = NULL;
- unsigned int evt_i = 0, evt_num = 0;
- bool evt_num_known = false;
-
-restart:
- sys_dir = tracing_events__opendir();
- if (!sys_dir)
- return;
-
- if (evt_num_known) {
- evt_list = zalloc(sizeof(char *) * evt_num);
- if (!evt_list)
- goto out_close_sys_dir;
- }
+ struct dirent **sys_namelist = NULL;
+ bool printed = false;
+ int sys_items = tracing_events__scandir_alphasort(&sys_namelist);
+
+ for (int i = 0; i < sys_items; i++) {
+ struct dirent *sys_dirent = sys_namelist[i];
+ struct dirent **evt_namelist = NULL;
+ char *dir_path;
+ int evt_items;
+
+ if (sys_dirent->d_type != DT_DIR ||
+ !strcmp(sys_dirent->d_name, ".") ||
+ !strcmp(sys_dirent->d_name, ".."))
+ continue;

- for_each_subsystem(sys_dir, sys_dirent) {
if (subsys_glob != NULL &&
!strglobmatch(sys_dirent->d_name, subsys_glob))
continue;
@@ -93,69 +88,40 @@ void print_tracepoint_events(const char *subsys_glob,
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) {
- if (event_glob != NULL &&
- !strglobmatch(evt_dirent->d_name, event_glob))
+ evt_items = scandir(dir_path, &evt_namelist, NULL, alphasort);
+ for (int j = 0; j < evt_items; j++) {
+ struct dirent *evt_dirent = evt_namelist[j];
+ char evt_path[MAXPATHLEN];
+
+ if (evt_dirent->d_type != DT_DIR ||
+ !strcmp(evt_dirent->d_name, ".") ||
+ !strcmp(evt_dirent->d_name, ".."))
continue;

- if (!evt_num_known) {
- evt_num++;
+ if (tp_event_has_id(dir_path, evt_dirent) != 0)
+ continue;
+
+ if (event_glob != NULL &&
+ !strglobmatch(evt_dirent->d_name, event_glob))
continue;
- }

snprintf(evt_path, MAXPATHLEN, "%s:%s",
sys_dirent->d_name, evt_dirent->d_name);
-
- evt_list[evt_i] = strdup(evt_path);
- if (evt_list[evt_i] == NULL) {
- put_events_file(dir_path);
- goto out_close_evt_dir;
+ if (name_only)
+ printf("%s ", evt_path);
+ else {
+ printf(" %-50s [%s]\n", evt_path,
+ event_type_descriptors[PERF_TYPE_TRACEPOINT]);
}
- evt_i++;
+ printed = true;
}
- closedir(evt_dir);
-next:
- put_events_file(dir_path);
+ free(dir_path);
+ free(evt_namelist);
}
- closedir(sys_dir);
-
- if (!evt_num_known) {
- evt_num_known = true;
- goto restart;
- }
- qsort(evt_list, evt_num, sizeof(char *), cmp_string);
- evt_i = 0;
- while (evt_i < evt_num) {
- if (name_only) {
- printf("%s ", evt_list[evt_i++]);
- continue;
- }
- printf(" %-50s [%s]\n", evt_list[evt_i++],
- event_type_descriptors[PERF_TYPE_TRACEPOINT]);
- }
- if (evt_num && pager_in_use())
+ free(sys_namelist);
+ if (printed && pager_in_use())
printf("\n");
-
-out_free:
- evt_num = evt_i;
- for (evt_i = 0; evt_i < evt_num; evt_i++)
- zfree(&evt_list[evt_i]);
- zfree(&evt_list);
- return;
-
-out_close_evt_dir:
- closedir(evt_dir);
-out_close_sys_dir:
- closedir(sys_dir);
-
- printf("FATAL: not enough memory to print %s\n",
- event_type_descriptors[PERF_TYPE_TRACEPOINT]);
- if (evt_list)
- goto out_free;
}

void print_sdt_events(const char *subsys_glob, const char *event_glob,
--
2.38.1.431.g37b22c650d-goog