Re: [RFC 0/1] integrate dmadev in vhost

[fengchengwen <fengchengwen@huawei.com>]

Hi Jiayu

I notice that examples/vhost rely on VMDQ, Could the examples/vhost provide
options that do not depend on VMDQ?  In this way, many network adapters can
be used.

Thanks.


On 2021/11/22 18:54, Jiayu Hu wrote:
> Since dmadev is introduced in 21.11, to avoid the overhead of vhost DMA
> abstraction layer and simplify application logics, this patch integrates
> dmadev in vhost.
> 
> To enable the flexibility of using DMA devices in different function
> modules, not limited in vhost, vhost doesn't manage DMA devices.
> Applications, like OVS, need to manage and configure DMA devices and
> tell vhost what DMA device to use in every dataplane function call.
> 
> In addition, vhost supports M:N mapping between vrings and DMA virtual
> channels. Specifically, one vring can use multiple different DMA channels
> and one DMA channel can be shared by multiple vrings at the same time.
> The reason of enabling one vring to use multiple DMA channels is that
> it's possible that more than one dataplane threads enqueue packets to
> the same vring with their own DMA virtual channels. Besides, the number
> of DMA devices is limited. For the purpose of scaling, it's necessary to
> support sharing DMA channels among vrings.
> 

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