[PATCH v2] dts: testpmd link check on port start

[Andrew Bailey]

 Raises:
+        InteractiveCommandExecutionError: If the ports has been started
but a port link will not come up.
nit: fails check-format because the line is too long.

Reviewed-by: Andrew Bailey <abailey at iol.unh.edu>

On Wed, Nov 5, 2025 at 2:50 PM Patrick Robb <probb at iol.unh.edu> wrote:

> When running our existing DTS testsuites on a new
> NIC we observed packets would not transmit from
> the traffic generator to the system under test
> even after DPDK testpmd and the NIC under test
> had indicated readiness. After investigation, we
> determined that the existing readiness check in DTS
> for testpmd start (checking that port is started)
> is insufficient, because on some systems the link
> will remain down for some measurable time, creating
> a race condition between the testpmd port's link
> coming up and the DTS execution reaching the packet
> transmission step. This change will ensure that
> testpmd start will block until the port is reporting
> that its link is up. In addition, the interval in
> between checking the link state has been reduced in
> order to speed up the execution.
>
> Signed-off-by: Patrick Robb <probb at iol.unh.edu>
> Tested-by: Patrick Robb <probb at iol.unh.edu>
> ---
>  dts/api/testpmd/__init__.py | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/dts/api/testpmd/__init__.py b/dts/api/testpmd/__init__.py
> index aadb7f4e70..49a847494a 100644
> --- a/dts/api/testpmd/__init__.py
> +++ b/dts/api/testpmd/__init__.py
> @@ -93,6 +93,9 @@ def _requires_started_ports(func: TestPmdMethod) ->
> TestPmdMethod:
>
>      Args:
>          func: The :class:`TestPmd` method to decorate.
> +
> +    Raises:
> +        InteractiveCommandExecutionError: If the ports has been started
> but a port link will not come up.
>      """
>
>      @functools.wraps(func)
> @@ -100,6 +103,10 @@ def _wrapper(self: "TestPmd", *args: P.args,
> **kwargs: P.kwargs) -> Any:
>          if not self.ports_started:
>              self._logger.debug("Ports need to be started to continue.")
>              self.start_all_ports()
> +        if get_ctx().topology.type is not LinkTopology.NO_LINK:
> +            for port in self.ports:
> +                if not self.wait_link_status_up(port.id):
> +                    raise InteractiveCommandExecutionError(f"Port {
> port.id} link failed to come up.")
>
>          return func(self, *args, **kwargs)
>
> @@ -265,7 +272,7 @@ def wait_link_status_up(self, port_id: int,
> timeout=SETTINGS.timeout) -> bool:
>              port_info = self.send_command(f"show port info {port_id}")
>              if "Link status: up" in port_info:
>                  break
> -            time.sleep(0.5)
> +            time.sleep(0.25)
>          else:
>              self._logger.error(f"The link for port {port_id} did not come
> up in the given timeout.")
>          return "Link status: up" in port_info
> --
> 2.49.0
>
>
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