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

[Jiri Olsa <jolsa@redhat.com>]

On Wed, May 26, 2021 at 01:05:17AM +0200, Riccardo Mancini 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@gmail.com>
> Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Cc: Ian Rogers <irogers@google.com>

Acked-by: Jiri Olsa <jolsa@redhat.com>

thanks,
jirka

> ---
>  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++)	\
>  		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
>