Re: [dpdk-dev] [PATCH 2/2] fib: announce experimental tag removal of the fib API

[Jan Viktorin <viktorin@cesnet.cz>]

On Thu, 5 Aug 2021 15:27:15 +0200
"Medvedkin, Vladimir" <vladimir.medvedkin@intel.com> wrote:

> Hi Jan,
> 
> The RIB is always used as a control plane struct intended to maintain 
> the correct content of the dataplane struct, such as DIR24_8 for 
> example. So it is always used on _add()/_delete(). For simplicity you 
> can consider it as an LPM's rule_info. But instead of keeping routes
> in a plane array as it is in LPM, FIB uses RIB which is more suitable 
> binary tree.

OK. I thought that I can have a single RIB, use it for maintaining
routes and based on this single RIB, I can build a FIB for the data
plane. And when the single RIB is updated (which can take quite a lot
of time) I build a new FIB and locklessly give it to the dataplane.
Such approach is not considered?

Jan

> 
> 
> On 05/08/2021 15:14, Jan Viktorin wrote:
> > On Thu, 5 Aug 2021 15:08:13 +0200
> > Vladimir Medvedkin <vladimir.medvedkin@intel.com> wrote:
> >   
> >> This patch announces the experimental tag removal of all fib APIs,
> >> which have been experimental for 2 years.
> >> API will be promoted to stable in DPDK 21.11  
> > 
> > Hi Vladimir,
> > 
> > I have a question related to FIB. I am just learning how to use it
> > and I found that each FIB always creates a new RIB internally.
> > There is no doc about this topic...
> > 
> > If I understand correctly, the underlying RIB is only used when
> > dummy_lookup() and dummy_modify() are used. But they are only used
> > when the configured mode is RTE_FIB_DUMMY. Is there any reason to
> > create the RIB with RTE_FIB_DIR24_8?
> > 
> > The issue with this is that each RIB allocates a new mempool
> > internally which can waste quite a lot of never used memory that
> > would be unused with DIR24_8 implementation.
> > 
> > Regards
> > Jan
> >   
> >>
> >>
> >> Signed-off-by: Vladimir Medvedkin <vladimir.medved...@intel.com>
> >> ---
> >>   doc/guides/rel_notes/deprecation.rst | 2 ++
> >>   1 file changed, 2 insertions(+)
> >>
> >> diff --git a/doc/guides/rel_notes/deprecation.rst
> >> b/doc/guides/rel_notes/deprecation.rst
> >> index afb599a..58826a8 100644
> >> --- a/doc/guides/rel_notes/deprecation.rst
> >> +++ b/doc/guides/rel_notes/deprecation.rst
> >> @@ -195,3 +195,5 @@ Deprecation Notices
> >>     communicate events such as soft expiry with IPsec in lookaside
> >> mode.
> >>   * rib: The ``rib`` library will be promoted from experimental to
> >> stable. +
> >> +* fib: The ``fib`` library will be promoted from experimental to
> >> stable.  
>