Re: [PATCH v2 mptcp-next] selftests: mptcp: fix diag instability

[Matthieu Baerts <matthieu.baerts@tessares.net>]

Hi Paolo,

On 04/02/2022 13:17, Paolo Abeni wrote:
> Instead of waiting for an arbitrary amount of time for the MPTCP
> MP_CAPABLE handshake to complete, explicitly wait for the relevant
> socket to enter into the established status.
> 
> Additionally let the data transfer application use the slowest
> transfer mode available (-r), to cope with very slow host, or
> high jitter caused by hosting VMs.
> 
> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
> ---
> v1 -> v2:
>  - use wait_for_ instead larger sleep
>  - hopefully better commit message

Thank you for the new version!

It is being tested in the background. More than 175 attempts in a slow
environment with a debug kernel and no failures so far!

> diff --git a/tools/testing/selftests/net/mptcp/diag.sh b/tools/testing/selftests/net/mptcp/diag.sh
> index 2674ba20d524..ff821025d309 100755
> --- a/tools/testing/selftests/net/mptcp/diag.sh
> +++ b/tools/testing/selftests/net/mptcp/diag.sh-
> @@ -119,7 +149,7 @@ for I in `seq 1 $NR_CLIENTS`; do
>  				./mptcp_connect -p $((I+10001)) -l -w 10 \
>  					-t ${timeout_poll} 0.0.0.0 >/dev/null &
>  done
> -sleep 0.1
> +wait_local_port_listen $ns $((NR_CLIENTS + 10001))
>  
>  for I in `seq 1 $NR_CLIENTS`; do
>  	echo "b" | \

Do we need the change the last sleep (sleep 1.5) as well? We could wait
for a shorter time but well that's only 1.5 second once. And I guess we
might need to look for each connection because looking at the last one
might not be enough if there was an issue with a previous one.

So best to keep the "sleep 1.5"?

If yes, do you prefer if the test run for a longer time or can I already
apply it?

Just in case:

Reported-and-tested-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/258

Cheers,
Matt
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