Re: [dpdk-dev] [PATCH v4] examples/l2fwd: add cmdline option for forwarding port info

[Jerin Jacob <jerinjacobk@gmail.com>]

On Mon, May 25, 2020 at 2:59 PM Bruce Richardson
<bruce.richardson@intel.com> wrote:
>
> On Sun, May 24, 2020 at 06:13:22PM +0200, Thomas Monjalon wrote:
> > Bruce, as maintainer of l2fwd example, any opinion about this change?
> >
> Assuming all previous discussion on it is resolved, I'm fine with this
> patch, though I suspect it will only make 20.08 now.
>
> Acked-by: Bruce Richardson <bruce.richardson@intel.com>

Ping for merge.


>
> >
> > 11/05/2020 02:23, Pavan Nikhilesh Bhagavatula:
> > > Hi Vipin,
> > >
> > > >Hi Pavan,
> > > >
> > > >snipped
> > > >> >
> > > >> >Should we check & warn the user if
> > > >> >1. port speed mismatch
> > > >> >2. on different NUMA
> > > >> >3. port pairs are physical and vdev like tap, and KNI (performance).
> > > >> >
> > > >>
> > > >> Sure, it can be a separate patch as it will be applicable for multiple
> > > >examples.
> > > >I believe this patch is for example `l2fwd`. But you would like to have to
> > > >updated for all `example`. I am ok for this.
> > > >
> > > >snipped
> > > >> >
> > > >> >Should not the check_port_pair be after this? If the port is not
> > > >> >enabled in port_mask will you skip that pair? or skip RX-TX from that
> > > >port?
> > > >>
> > > >> We check every port pair against l2fwd_enabled_port_mask in
> > > >> check_port_pair_config()
> > > >
> > > >
> > > >>
> > > >snipped
> > > >> >
> > > >> >As mentioned above there can ports in mask which might be
> > > >disabled for
> > > >> >port pair. Should not that be skipped rather than setting last port rx-
> > > >> >tx loopback?
> > > >>
> > > >> There could be scenarios where user might want to test 2x10G and
> > > >1x40G Why
> > > >> force the user to explicitly mention 1x40G as port pair of itself in the
> > > >portpair
> > > >> config?
> > > >I am not sure if I follow your thought, as your current port map only
> > > >allows `1:1` mapping by `struct port_pair_params`. This can be to self
> > > >like `(port0:port0),(port1:port1)` or `(port-0:port-1)`.
> > > >
> > > >1. But current `l2fwd_parse_port_pair_config` does not consider the
> > > >same port mapping as we have hard check for `if (nb_port_pair_params
> > > >>= RTE_MAX_ETHPORTS/2)`.
> > > >
> > > >2. `l2fwd_enabled_port_mask` is global variable of user port mask. This
> > > >can contain both valid and invalid mask. Hence we check
> > > >`l2fwd_enabled_port_mask & ~((1 << nb_ports) - 1)`.
> > > >
> > > >3. can these scenarios are true if we invoke `check_port_pair_config`
> > > >before actual port_mask check.
> > > > a. there are only 4 ports, hence possible mask is `0xf`.
> > > > b. user passes port argument as `0xe`
> > > > c. `check_port_pair_config` gets masks for `(1,3)` as input and
> > > >populates `port_pair_config_mask`.
> > > > d.  As per the code, port 2 which is valid port and part of user port mask
> > > >will have lastport (which is port 3)? May be I did understand the logic
> > > >correct. Can you help me?
> > >
> > > Here user needs to explicitly mention (2,2) for port 2 to be setup else it
> > > will be skipped.
> > > If you see `check_port_pair_config` below we disable the ports that are not
> > > Mentioned in portmap.
> > >
> > > "
> > > check_port_pair_config(void)
> > > {
> > >
> > > <snip>
> > >             port_pair_config_mask |= port_pair_mask;
> > >     }
> > >
> > >     l2fwd_enabled_port_mask &= port_pair_config_mask;
> > >
> > >     return 0;
> > > }
> > > "
> > >
> > >
> > > >
> > > >So my concerns are 1) there is no same port mapping, 2) my
> > > >understanding on lastport logic is not clear and 3) as per the code there
> > > >is 1:N but 1:1.
> > > >
> > > >Hence there should be sufficient warning to user if port are of wrong
> > > >speed and NUMA.
> > >
> > > Unless the user disables stats using -T 0 option all the prints will be skipped.
> > >
> > > >
> > > >Note: current speed can be fetched only if the port are started too (in
> > > >Fortville).
> > > >
> > > >snipped
> >
> >
> >
> >