Re: [PATCH bpf-next] selftests/bpf: adding delay in socketmap_listen to reduce flakyness

[Andrii Nakryiko <andrii.nakryiko@gmail.com>]

On Thu, Aug 19, 2021 at 12:16 PM sunyucong@gmail.com
<sunyucong@gmail.com> wrote:
>
> On Thu, Aug 19, 2021 at 11:45 AM Andrii Nakryiko
> <andrii.nakryiko@gmail.com> wrote:
> >
> > On Thu, Aug 19, 2021 at 9:36 AM Yucong Sun <fallentree@fb.com> wrote:
> > >
> > > This patch adds a 1ms delay to reduce flakyness of the test.
> > >
> > > Signed-off-by: Yucong Sun <fallentree@fb.com>
> > > ---
> >
> > Any reasons to not implement exponential back-off, like we did for test_maps?
>
> for simplicity, since there are no contention involved here I figured
> we don’t need random delay and back-offs.

Alright, it's an improvement anyways. Let's see if it still causes
problem. Applied to bpf-next, thanks!

>
> (sorry for resending, I was fooled by the mobile gmail client that it
> doesn't do plain text).
>

AFAIK, mobile client doesn't support plain text

>
> >
> > >  .../selftests/bpf/prog_tests/sockmap_listen.c        | 12 +++++++++---
> > >  1 file changed, 9 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_listen.c b/tools/testing/selftests/bpf/prog_tests/sockmap_listen.c
> > > index afa14fb66f08..6a5df28f9a3d 100644
> > > --- a/tools/testing/selftests/bpf/prog_tests/sockmap_listen.c
> > > +++ b/tools/testing/selftests/bpf/prog_tests/sockmap_listen.c
> > > @@ -1603,8 +1603,10 @@ static void unix_redir_to_connected(int sotype, int sock_mapfd,
> > >  again:
> > >         n = read(mode == REDIR_INGRESS ? p0 : c0, &b, 1);
> > >         if (n < 0) {
> > > -               if (errno == EAGAIN && retries--)
> > > +               if (errno == EAGAIN && retries--) {
> > > +                       usleep(1000);
> > >                         goto again;
> > > +               }
> > >                 FAIL_ERRNO("%s: read", log_prefix);
> > >         }
> > >         if (n == 0)
> > > @@ -1776,8 +1778,10 @@ static void udp_redir_to_connected(int family, int sock_mapfd, int verd_mapfd,
> > >  again:
> > >         n = read(mode == REDIR_INGRESS ? p0 : c0, &b, 1);
> > >         if (n < 0) {
> > > -               if (errno == EAGAIN && retries--)
> > > +               if (errno == EAGAIN && retries--) {
> > > +                       usleep(1000);
> > >                         goto again;
> > > +               }
> > >                 FAIL_ERRNO("%s: read", log_prefix);
> > >         }
> > >         if (n == 0)
> > > @@ -1869,8 +1873,10 @@ static void inet_unix_redir_to_connected(int family, int type, int sock_mapfd,
> > >  again:
> > >         n = read(mode == REDIR_INGRESS ? p0 : c0, &b, 1);
> > >         if (n < 0) {
> > > -               if (errno == EAGAIN && retries--)
> > > +               if (errno == EAGAIN && retries--) {
> > > +                       usleep(1000);
> > >                         goto again;
> > > +               }
> > >                 FAIL_ERRNO("%s: read", log_prefix);
> > >         }
> > >         if (n == 0)
> > > --
> > > 2.30.2
> > >