Re: vhost [query] : support for multiple ports and non VMDQ devices in vhost switch

Hi Jianfeng,

On 08/17/2016 04:33 AM, Tan, Jianfeng wrote:

Hi,

Please review below proposal of Pankaj and myself after an offline
discussion. (Pankaj, please correct me if I'm going somewhere wrong).

a. Remove HW dependent option, --strip-vlan, because different kinds of
NICs behave differently. It's a bug fix.
b. Abstract switching logic into a framework, so that we can develop
different kinds of switching logics. In this phase, we will have two
switching logics: (1) a simple software-based mac learning switching;
(2) VMDQ based switching. Any other advanced switching logics can be
proposed based on this framework.
c. Merge tep_termination example vxlan as a switching logic of the
framework.

I was also thinking of making physical port optional and add MAC learning,
so this is all good for me.

Let me know if I can help in implementation, I'll be happy to
contribute.

To be decided:
d. Support multiple physical ports.
e. Keep the current way to use vhost lib directly or use vhost pmd instead.

Do you see advantages of using vhost lib directly vs. pmd?
Wouldn't using vhost pmd make achieving zero-copy harder?
(I'm not sure, I didn't investigate the topic much for now).

Also, if we use pmd directly, then it would no more be a vhost switch
only, as it could potentially be used with physical NICs also.

Any thoughts?

Thanks,
Maxime

On 8/16/2016 10:56 AM, Yuanhan Liu wrote:

quoted

On Tue, Aug 09, 2016 at 04:42:33PM +0530, Pankaj Chauhan wrote:

quoted

Hi,

I am working on an NXP platform where we intend to use user space vhost
switch (examples/vhost) as backend for VIRTIO devices. But there are two
limitations in current vhost-switch (examples/vhost)that are
restricting my
use case:

1. The vhost-switch application is tightly integrated with Intel
VMDQ. Since
my device doesn't have VMDQ i can not use this application directly.

Sorry being late (I was on biz trip last week).

Yes, a vhost example should not do that. We have an internal TODO to
remove it. Actually, to make it optional, and Jianfeng was working on
that. Well, seems that you two have already had some discussions.

quoted

2. The vhost-switch application supports only one external or
physical port
(non virtio devices), but my requirement is to have multiple physical
ports
and multiple virtio devices.

What are you going to achieve? BTW, have you tried testpmd (with
vhost-pmd)?

Example testpmd will not allow those complex switching logics.

Thanks,
Jianfeng

quoted

I'm with impression that it might be a better option to you.

    --yliu

quoted

In summary my requirement is to do whatever vhost-switch is doing, in
addition to that add support for following:

1. support devices that don't have VMDQ.
2. Support multiple physical ports.

I need suggestions on the approach i should take: whether to add
support of
above mentioned in existing vhost-switch (examples/vhost) or write
another
application (based on librte_vhost only) to support my requirements.

I'll work on it after the suggestion i get from the list, and send
the RFC
patch.

Thanks,
Pankaj