Re: [PATCH] perf test: iterate over shell tests in alphabetical order

From: Ian Rogers
Date: Tue May 25 2021 - 19:26:07 EST


On Tue, May 25, 2021 at 4:08 PM Riccardo Mancini <rickyman7@xxxxxxxxx> wrote:
>
> for_each_shell_test macro iterated over all shell tests in the directory
> using readdir, which does not guarantee any ordering, causing
> problems on certain fs. However, the order in which they are visited
> determines the id of the test, in case one wants to run a single test.
>
> This patch replaces readdir with scandir using alphabetical sorting.
> This guarantees that, given the same set of tests, all machines will
> see the tests in the same order, and, thus, that test ids are
> consistent.
>
> Signed-off-by: Riccardo Mancini <rickyman7@xxxxxxxxx>
> Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
> Cc: Ian Rogers <irogers@xxxxxxxxxx>

Acked-by: Ian Rogers <irogers@xxxxxxxxxx>

> ---
> tools/perf/tests/builtin-test.c | 38 ++++++++++++++++++---------------
> 1 file changed, 21 insertions(+), 17 deletions(-)
>
> diff --git a/tools/perf/tests/builtin-test.c b/tools/perf/tests/builtin-test.c
> index c4b888f18e9ca..cbbfe48ab8029 100644
> --- a/tools/perf/tests/builtin-test.c
> +++ b/tools/perf/tests/builtin-test.c
> @@ -510,8 +510,8 @@ static const char *shell_test__description(char *description, size_t size,
> return description ? strim(description + 1) : NULL;
> }
>
> -#define for_each_shell_test(dir, base, ent) \
> - while ((ent = readdir(dir)) != NULL) \
> +#define for_each_shell_test(entlist, nr, base, ent) \
> + for (int __i = 0; __i < nr && (ent = entlist[__i]); __i++) \

I think this declaration of __i is okay as C99 allows declarations
here, but generally I don't see this style in the kernel.

Thanks,
Ian

> if (!is_directory(base, ent) && ent->d_name[0] != '.')
>
> static const char *shell_tests__dir(char *path, size_t size)
> @@ -538,8 +538,9 @@ static const char *shell_tests__dir(char *path, size_t size)
>
> static int shell_tests__max_desc_width(void)
> {
> - DIR *dir;
> + struct dirent **entlist;
> struct dirent *ent;
> + int n_dirs;
> char path_dir[PATH_MAX];
> const char *path = shell_tests__dir(path_dir, sizeof(path_dir));
> int width = 0;
> @@ -547,11 +548,11 @@ static int shell_tests__max_desc_width(void)
> if (path == NULL)
> return -1;
>
> - dir = opendir(path);
> - if (!dir)
> + n_dirs = scandir(path, &entlist, NULL, alphasort);
> + if (n_dirs == -1)
> return -1;
>
> - for_each_shell_test(dir, path, ent) {
> + for_each_shell_test(entlist, n_dirs, path, ent) {
> char bf[256];
> const char *desc = shell_test__description(bf, sizeof(bf), path, ent->d_name);
>
> @@ -563,7 +564,8 @@ static int shell_tests__max_desc_width(void)
> }
> }
>
> - closedir(dir);
> + free(entlist);
> +
> return width;
> }
>
> @@ -589,8 +591,9 @@ static int shell_test__run(struct test *test, int subdir __maybe_unused)
>
> static int run_shell_tests(int argc, const char *argv[], int i, int width)
> {
> - DIR *dir;
> + struct dirent **entlist;
> struct dirent *ent;
> + int n_dirs;
> char path_dir[PATH_MAX];
> struct shell_test st = {
> .dir = shell_tests__dir(path_dir, sizeof(path_dir)),
> @@ -599,14 +602,14 @@ static int run_shell_tests(int argc, const char *argv[], int i, int width)
> if (st.dir == NULL)
> return -1;
>
> - dir = opendir(st.dir);
> - if (!dir) {
> + n_dirs = scandir(st.dir, &entlist, NULL, alphasort);
> + if (n_dirs == -1) {
> pr_err("failed to open shell test directory: %s\n",
> st.dir);
> return -1;
> }
>
> - for_each_shell_test(dir, st.dir, ent) {
> + for_each_shell_test(entlist, n_dirs, st.dir, ent) {
> int curr = i++;
> char desc[256];
> struct test test = {
> @@ -623,7 +626,7 @@ static int run_shell_tests(int argc, const char *argv[], int i, int width)
> test_and_print(&test, false, -1);
> }
>
> - closedir(dir);
> + free(entlist);
> return 0;
> }
>
> @@ -722,19 +725,20 @@ static int __cmd_test(int argc, const char *argv[], struct intlist *skiplist)
>
> static int perf_test__list_shell(int argc, const char **argv, int i)
> {
> - DIR *dir;
> + struct dirent **entlist;
> struct dirent *ent;
> + int n_dirs;
> char path_dir[PATH_MAX];
> const char *path = shell_tests__dir(path_dir, sizeof(path_dir));
>
> if (path == NULL)
> return -1;
>
> - dir = opendir(path);
> - if (!dir)
> + n_dirs = scandir(path, &entlist, NULL, alphasort);
> + if (n_dirs == -1)
> return -1;
>
> - for_each_shell_test(dir, path, ent) {
> + for_each_shell_test(entlist, n_dirs, path, ent) {
> int curr = i++;
> char bf[256];
> struct test t = {
> @@ -747,7 +751,7 @@ static int perf_test__list_shell(int argc, const char **argv, int i)
> pr_info("%2d: %s\n", i, t.desc);
> }
>
> - closedir(dir);
> + free(entlist);
> return 0;
> }
>
> --
> 2.31.1
>