Re: [PATCH v3] app/testpmd: add parameter to start forwarding TX first

[Thomas Monjalon <thomas@monjalon.net>]

15/06/2017 14:05, De Lara Guarch, Pablo:
> > Add parameter to start forwarding sending first
> > a burst of packets, which is useful when testing
> > a loopback connection.
> > 
> > This was already implemented as an internal command,
> > but adding it as a parameter is interesting, as it
> > allows the user to test a loopback connection without
> > entering in the internal command line.
> > 
> > Signed-off-by: Pablo de Lara <pablo.de.lara.guarch@intel.com>
> > ---
> > --- a/doc/guides/testpmd_app_ug/run_app.rst
> > +++ b/doc/guides/testpmd_app_ug/run_app.rst
> > @@ -188,6 +188,14 @@ The commandline options are:
> > 
> >      Start forwarding on initialization.
> > 
> > +*   ``--tx-first``
> > +
> > +    Start forwarding, after sending a burst of packets first.
> > +
> > +.. Note::
> > +
> > +   This flag should be only used in non-interactive mode.

I don't really understand the benefit of this option.
Why is it better than
	echo start tx_first | testpmd -i
?