[PATCH v5] net/vhost: support asynchronous data path

[Xia, Chenbo]

Hi Yuan,

> -----Original Message-----
> From: Wang, YuanX <yuanx.wang at intel.com>
> Sent: Monday, October 24, 2022 11:15 PM
> To: Maxime Coquelin <maxime.coquelin at redhat.com>; Xia, Chenbo
> <chenbo.xia at intel.com>
> Cc: dev at dpdk.org; Hu, Jiayu <jiayu.hu at intel.com>; Jiang, Cheng1
> <cheng1.jiang at intel.com>; Ma, WenwuX <wenwux.ma at intel.com>; He, Xingguang
> <xingguang.he at intel.com>; Wang, YuanX <yuanx.wang at intel.com>
> Subject: [PATCH v5] net/vhost: support asynchronous data path
> 
> Vhost asynchronous data-path offloads packet copy from the CPU
> to the DMA engine. As a result, large packet copy can be accelerated
> by the DMA engine, and vhost can free CPU cycles for higher level
> functions.
> 
> In this patch, we enable asynchronous data-path for vhostpmd.
> Asynchronous data path is enabled per tx/rx queue, and users need
> to specify the DMA device used by the tx/rx queue. Each tx/rx queue
> only supports to use one DMA device, but one DMA device can be shared
> among multiple tx/rx queues of different vhost PMD ports.
> 
> Two PMD parameters are added:
> - dmas:	specify the used DMA device for a tx/rx queue.
> 	(Default: no queues enable asynchronous data path)
> - dma-ring-size: DMA ring size.
> 	(Default: 4096).
> 
> Here is an example:
> --vdev
> 'eth_vhost0,iface=./s0,dmas=[txq0 at 0000:00.01.0;rxq0 at 0000:00.01.1],dma-
> ring-size=4096'
> 
> Signed-off-by: Jiayu Hu <jiayu.hu at intel.com>
> Signed-off-by: Yuan Wang <yuanx.wang at intel.com>
> Signed-off-by: Wenwu Ma <wenwux.ma at intel.com>
> 

Sorry that I just realize that we need to change release notes because this
is new feature for vhost PMD. Please mention the async support and new driver
api you added.

Thanks,
Chenbo