[dpdk-dev] [PATCH v5 3/4] vhost: support async dequeue for split ring

[David Marchand]

On Wed, Jul 14, 2021 at 8:50 AM Hu, Jiayu <jiayu.hu at intel.com> wrote:
> > Are we ensuring packets are not reordered with this way of working?
>
> There is a threshold can be set by users. If set it to 0, which presents all
> packet copies assigned to the DMA, the packets sent from the guest will
> not be reordered.

- I find the rte_vhost_async_channel_register() signature with a
bitfield quite ugly.
We are writing sw, this is not mapped to hw stuff... but ok this is a
different topic.


- I don't like this threshold, this is too low level and most users
will only see the shiny aspect "better performance" without
understanding the consequences.
By default, it leaves the door open to a _bad_ behavior, that is
packet reordering.
At a very minimum, strongly recommend to use 0 in the API.



-- 
David Marchand