Re: [dpdk-dev] [PATCH v3 0/2] slow data path communication between DPDK port and Linux

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 3/16/2016 10:45 AM, Thomas Monjalon wrote:
> 2016-03-16 10:26, Ferruh Yigit:
>> On 3/16/2016 8:22 AM, Panu Matilainen wrote:
>>> On 03/16/2016 10:19 AM, Ferruh Yigit wrote:
>>>> On 3/16/2016 7:26 AM, Panu Matilainen wrote:
>>>>> On 03/14/2016 05:32 PM, Ferruh Yigit wrote:
>>>>>> On 3/9/2016 11:17 AM, Ferruh Yigit wrote:
>>>>>>> This patch sent to keep record of latest status of the work.
>>>>>>>
>>>>>>>
>>>>>>> This is slow data path communication implementation based on existing KNI.
>>>>>>>
>>>>>>> Difference is: librte_kni converted into a PMD, kdp kernel module is almost
>>>>>>> same except all control path functionality removed and some simplification done.
>>>>>>>
>>>>>>> Motivation is to simplify slow path data communication.
>>>>>>> Now any application can use this new PMD to send/get data to Linux kernel.
>>>>>>>
>>>>>>> PMD supports two communication methods:
>>>>>>>
>>>>>>> 1) KDP kernel module
>>>>>>> PMD initialization functions handles creating virtual interfaces (with help of
>>>>>>> kdp kernel module) and created FIFO. FIFO is used to share data between
>>>>>>> userspace and kernelspace. This is default method.
>>>>>>>
>>>>>>> 2) tun/tap module
>>>>>>> When KDP module is not inserted, PMD creates tap interface and transfers
>>>>>>> packets using tap interface.
>>>>>>>
>>>>>>> In long term this patch intends to replace the KNI and KNI will be
>>>>>>> depreciated.
>>>>>>>
>>>>>>
>>>>>> Self-NACK: Will work on another option that does not introduce new
>>>>>> kernel module.
>>>>>>
>>>>>
>>>>> Hmm, care to elaborate a bit? The second mode of this PMD already was
>>>>> free of external kernel modules. Do you mean you'll be just removing
>>>>> mode 1) from the PMD or looking at something completely different?
>>>>>
>>>>> Just thinking that tun/tap PMD sounds like a useful thing to have, I
>>>>> hope you're not abandoning that.
>>>>>
>>>>
>>>> It will be KNI PMD.
>>>> Plan is to have something like KDP, but with existing KNI kernel module.
>>>> There will be tun/tap support as fallback.
>>>
>>> Hum, now I'm confused. I was under the impression everybody hated KNI 
>>> and wanted to get rid of it, and certainly not build future solutions on 
>>> top of it?
>>
>> We can't remove it.
> 
> Why?
> 
>> We can't replace/improve it -you were one of the major opposition to this.
>> This doesn't leave more option other than using it.
> 
> Why cannot we replace it by something upstream?
> 
I doubt KDP is upstream-able to Linux community. If somebody can, that
is great.

Even for KCP, upstreaming task is still under discussion, and as a heads
up, it is likely to be dropped.

Regards,
ferruh

>> There won't be any update in KNI kernel module, library + sample app
>> will be converted into PMD.
> 
>