On Tue, 13 Apr 2021 15:40:24 -0700 Saeed Mahameed wrote:
> > > Hence, allow user to disable metadata using driver specific devlink
> > > parameter.
> > >
> > > Example to show and disable metadata before changing eswitch mode:
> > > $ devlink dev param show pci/0000:06:00.0 name esw_port_metadata
> > > pci/0000:06:00.0:
> > > name esw_port_metadata type driver-specific
> > > values:
> > > cmode runtime value true
> > >
> > > $ devlink dev param set pci/0000:06:00.0 \
> > > name esw_port_metadata value false cmode runtime
> > >
> > > $ devlink dev eswitch set pci/0000:06:00.0 mode switchdev
> >
> > Is this something that only gets enabled when device is put into
> > switchdev mode? That needs to be clarified in the documentation IMO
> > to give peace of mind to all users who don't enable switchdev.
>
> Currently this is always enabled when switchdev is turned on, it
> affects the whole operation mode of the FDB and the offloaded flows so
> it can't be dynamic, it must be decided before user enables switchdev,
> it is needed only to allow LAG use cases, hence we add a disable knob
> for those who don't want LAG and could use some more packet rate.
>
> Some documentation was pushed as part of this patch:
> please let me know if it needs improvement. (maybe we should add the
> benefit of packet rate ?)
Right, I didn't see the info on when the performance impact is felt
in the documentation either.
AFAIU we have 3 categories of users:
1 - those who use esw|roce + LAG etc and therefore must leave this
enabled;
2 - those who don't use LAG but use switchdev so they can turn it off;
3 - those who don't use switchdev or RoCE..
While the documentation should be clear for 1 and 2, group 3 does not
know (a) if they will be impacted; or (b) may not even know what kind
of stacked devices documentation is referring to.
