Re: [dpdk-dev] [PATCH 1/2] ethdev: add flow action type update as an offload

[Ori Kam <orika@mellanox.com>]

Hi Andrew,

> -----Original Message-----
> From: Andrew Rybchenko <arybchenko@solarflare.com>
> Subject: Re: [dpdk-dev] [PATCH 1/2] ethdev: add flow action type update as an
> offload
> 
> Hi Ori,
> 
> On 10/28/19 1:50 PM, Ori Kam wrote:
> > Hi Pavan,
> >
> > Sorry for jumping in late.
> >
> > I don't understand why we need this feature. If the user didn't set any flow
> with MARK
> > then the user doesn't need to check it.
> 
> There is pretty long discussion on the topic already, please, read [1].
> 
> [1]
> https://eur03.safelinks.protection.outlook.com/?url=http%3A%2F%2Finbox.dpdk
> .org%2Fdev%2F3251fc00-7598-1c4f-fc2a-
> 380065f0a435%40solarflare.com%2F&amp;data=02%7C01%7Corika%40mellan
> ox.com%7Ce3f779d4b7c44b682d6508d75b9d8688%7Ca652971c7d2e4d9ba6a4
> d149256f461b%7C0%7C0%7C637078604439019114&amp;sdata=sYooc%2FQ3C
> kUZG3gRFPlZrm8xMfMB9gOWWex5YIkWhMc%3D&amp;reserved=0
> 

Thanks for the link, it was an interesting reading.

> > Also it breaks compatibility.
> 
> Yes, there is a deprecation notice for it.
> 
> > If my understanding is correct the MARK field is going to be moved to
> dynamic field, and this
> > will be way to control the use of MARK.
> 
> Yes and I think the offload should used to request dynamic
> field register. Similar to timestamp in dynamic mbuf examples.
> Application requests Rx timestamp offload, PMD registers dynamic
> filed.
> 

In general it was decided that there will be no capability for rte_flow API, due to the fact that 
it is impossible to support all possible combinations. For example a PMD can allow mark on Rx
while not supporting it on e-switch (transfer) or on Tx.
The only way to validate it is validating a flow. If the flow is validated then the action is supported.
This is the exact approach we are implementing with the Meta feature.
So as I see it, the logic should be something like this:
1. run devconfigure.
2. allocate mempool
3. setup queues.
4. run rte_flow_validate with mark action.
If flow validated register mark in mbuf else don't register.
If the PMD needs some special setting for mark he can update the queue when he gets the flow to validate.
At this stage the device is not started so any change is allowed.





> > Other option is inside the PMD if one flow uses mark only than copy the mark
> to mbuf.
> >
> > Please also not that we have deprecation notice on the FDIR.
> >
> > Thanks,
> > Ori

Thanks,
Ori 

[snip]