On 10/10/18 12:00 PM, Ori Kam wrote:
-----Original Message-----
From: Andrew Rybchenko <arybche...@solarflare.com>
Sent: Wednesday, October 10, 2018 9:45 AM
To: Ferruh Yigit <ferruh.yi...@intel.com>; Ori Kam <or...@mellanox.com>;
step...@networkplumber.org; Adrien Mazarguil
<adrien.mazarg...@6wind.com>; Declan Doherty <declan.dohe...@intel.com>
Cc: dev@dpdk.org; Dekel Peled <dek...@mellanox.com>; Thomas Monjalon
<tho...@monjalon.net>; Nélio Laranjeiro <nelio.laranje...@6wind.com>;
Yongseok Koh <ys...@mellanox.com>; Shahaf Shuler
<shah...@mellanox.com>
Subject: Re: [PATCH v3 0/3] ethdev: add generic L2/L3 tunnel encapsulation
actions
On 10/9/18 7:48 PM, Ferruh Yigit wrote:
On 10/7/2018 1:57 PM, Ori Kam wrote:
This series implement the generic L2/L3 tunnel encapsulation actions
and is based on rfc [1] "add generic L2/L3 tunnel encapsulation actions"
Currenlty the encap/decap actions only support encapsulation
of VXLAN and NVGRE L2 packets (L2 encapsulation is where
the inner packet has a valid Ethernet header, while L3 encapsulation
is where the inner packet doesn't have the Ethernet header).
In addtion the parameter to to the encap action is a list of rte items,
this results in 2 extra translation, between the application to the action
and from the action to the NIC. This results in negetive impact on the
insertion performance.
Looking forward there are going to be a need to support many more tunnel
encapsulations. For example MPLSoGRE, MPLSoUDP.
Adding the new encapsulation will result in duplication of code.
For example the code for handling NVGRE and VXLAN are exactly the same,
and each new tunnel will have the same exact structure.
This series introduce a generic encapsulation for L2 tunnel types, and
generic encapsulation for L3 tunnel types. In addtion the new
encapsulations commands are using raw buffer inorder to save the
converstion time, both for the application and the PMD.
[1]https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fmail
s.dpdk.org%2Farchives%2Fdev%2F2018-
August%2F109944.html&data=02%7C01%7Corika%40mellanox.com%7C468bfe
a033d642c3af5a08d62e7c0bd2%7Ca652971c7d2e4d9ba6a4d149256f461b%7C0
%7C0%7C636747507642154668&sdata=cAMr3ThkyhjFrGv6K%2FvIDKHAskzMZI
E8cpRTWiBl1eA%3D&reserved=0
v3:
* rebase on tip.
v2:
* add missing decap_l3 structure.
* fix typo.
Ori Kam (3):
ethdev: add generic L2/L3 tunnel encapsulation actions
app/testpmd: convert testpmd encap commands to new API
ethdev: remove vxlan and nvgre encapsulation commands
Reminder of this patchset, any reviews welcome.
I've added the author of previous actions in recipients.
I like the idea to generalize encap/decap actions. It makes a bit harder
for reader to find which encap/decap actions are supported in fact,
but it changes nothing for automated usage in the code - just try it
(as a generic way used in rte_flow).
Even now the user doesn't know which encapsulation is supported since
it is PMD and sometime kernel related. On the other end it simplify adding
encapsulation to specific costumers with some time just FW update.
I was just trying to say that previous way is a bit easier to understand
from sources that PMD pretends to support VXLAN or NVGRE encap/decap.
In any case it is not that important, so OK to have the new way.
Arguments about a way of encap/decap headers specification (flow items
vs raw) sound sensible, but I'm not sure about it.
It would be simpler if the tunnel header is added appended or removed
as is, but as I understand it is not true. For example, IPv4 ID will be
different in incoming packets to be decapsulated and different values
should be used on encapsulation. Checksums will be different (but
offloaded in any case).
I'm not sure I understand your comment.
Decapsulation is independent of encapsulation, for example if we decap
L2 tunnel type then there is no parameter at all the NIC just removes
the outer layers.
OK, I've just mixed filtering and action parameters for decaps. My bad.
The argument for encapsulation still makes sense since the header is not
appended just as is. IP IDs change, lengths change, checksums change,
however, I agree that it is natural and expected behaviour.
Current way allows to specify which fields do not matter and which one
must match. It allows to say that, for example, VNI match is sufficient
to decapsulate.
The encapsulation according to definition, is a list of headers that should
encapsulate the packet. So I don't understand your comment about matching
fields. The matching is based on the flow and the encapsulation is just data
that should be added on top of the packet.
Yes, my bad as I've described above.
Also arguments assume that action input is accepted as is by the HW.
It could be true, but could be obviously false and HW interface may
require parsed input (i.e. driver must parse the input buffer and extract
required fields of packet headers).
You are correct there some PMD even Mellanox (for the E-Switch) require to
parsed input
There is no driver that knows rte_flow structure so in any case there should be
Some translation between the encapsulation data and the NIC data.
I agree that writing the code for translation can be harder in this approach,
but the code is only written once is the insertion speed is much higher this
way.
Also like I said some Virtual Switches are already store this data in raw buffer
(they update only specific fields) so this will also save time for the
application when
creating a rule.
Yes, makes sense.
So, I'd say no. It should be better motivated if we change existing
approach (even advertised as experimental).
I think the reasons I gave are very good motivation to change the approach
please also consider that there is no implementation yet that supports the old
approach.
while we do have code that uses the new approach.
It is really bad practice that features are accepted without at least
one implementation/usage.
Thanks for the reply. I'll provide my comments on patches.
