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

[Jiri Olsa <jolsa@redhat.com>]

On Tue, May 25, 2021 at 04:25:48PM -0700, Ian Rogers wrote:
> On Tue, May 25, 2021 at 4:08 PM Riccardo Mancini <rickyman7@gmail.com> 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: Ian Rogers <irogers@google.com>
> 
> > ---
> >  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.

I think it's ok, we have some instances of this in perf already..
otherwise we'd need to pass extra argument to the macro

jirka

> 
> 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
> >
>