[PATCH v2] doc: update async enqueue API usage

[Ding, Xuan]

Hi Chenbo,

> -----Original Message-----
> From: Xia, Chenbo <chenbo.xia at intel.com>
> Sent: Tuesday, June 21, 2022 9:23 PM
> To: Ding, Xuan <xuan.ding at intel.com>; maxime.coquelin at redhat.com
> Cc: dev at dpdk.org; Hu, Jiayu <jiayu.hu at intel.com>
> Subject: RE: [PATCH v2] doc: update async enqueue API usage
> 
> Hi Xuan,
> 
> > -----Original Message-----
> > From: Ding, Xuan <xuan.ding at intel.com>
> > Sent: Tuesday, June 21, 2022 3:22 PM
> > To: maxime.coquelin at redhat.com; Xia, Chenbo <chenbo.xia at intel.com>
> > Cc: dev at dpdk.org; Hu, Jiayu <jiayu.hu at intel.com>; Ding, Xuan
> > <xuan.ding at intel.com>
> > Subject: [PATCH v2] doc: update async enqueue API usage
> >
> > From: Xuan Ding <xuan.ding at intel.com>
> >
> > This patch updates the correct usage for async enqueue APIs.
> > The rte_vhost_poll_enqueue_completed() needs to be called in time to
> > notify the guest of completed packets and avoid packet loss.
> >
> > Signed-off-by: Xuan Ding <xuan.ding at intel.com>
> > ---
> > v2:
> > * refine doc and commit log
> > ---
> >  doc/guides/prog_guide/vhost_lib.rst | 8 ++++++++
> >  1 file changed, 8 insertions(+)
> >
> > diff --git a/doc/guides/prog_guide/vhost_lib.rst
> > b/doc/guides/prog_guide/vhost_lib.rst
> > index cd3f6caa9a..628db3fc38 100644
> > --- a/doc/guides/prog_guide/vhost_lib.rst
> > +++ b/doc/guides/prog_guide/vhost_lib.rst
> > @@ -480,6 +480,14 @@ 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.
> >
> > +* Async enqueue API usage
> > +
> > +  In async enqueue path, rte_vhost_poll_enqueue_completed() needs to
> > + be  called in time to notify the guest of DMA copy completed packets.
> > +  Moreover, calling rte_vhost_submit_enqueue_burst() all the time but
> > + not poll completed will cause the DMA ring to be full, which will
> > + result in packet loss eventually.
> > +
> 
> This subsection seems cleaner, could you also help to make 'Recommended
> IOVA mode in async datapath' as a sub-section?
> 
> Another patch or not, either works for me.

I will send a separate patch to move 'Recommended IOVA mode in async datapath' as a sub-section.

Thanks,
Xuan

> 
> Thanks,
> Chenbo
> 
> >  Recommended IOVA mode in async datapath
> >  ---------------------------------------
> >
> > --
> > 2.17.1