[dpdk-dev] [PATCH] doc: update virtio doc

Mcnamara, John john.mcnamara at intel.com
Wed May 10 11:58:24 CEST 2017



> -----Original Message-----
> From: Yang, Zhiyong
> Sent: Wednesday, May 10, 2017 7:18 AM
> To: dev at dpdk.org; Mcnamara, John <john.mcnamara at intel.com>
> Cc: yuanhan.liu at linux.intel.com; maxime.coquelin at redhat.com; Yang, Zhiyong
> <zhiyong.yang at intel.com>
> Subject: [PATCH] doc: update virtio doc
> 
> Add more explanations about vring size changes and virtio_header size.
> 
> Signed-off-by: Zhiyong Yang <zhiyong.yang at intel.com>
> ---
>  doc/guides/nics/virtio.rst | 13 +++++++++----
>  1 file changed, 9 insertions(+), 4 deletions(-)
> 
> diff --git a/doc/guides/nics/virtio.rst b/doc/guides/nics/virtio.rst index
> 91bedea..36ddd08 100644
> --- a/doc/guides/nics/virtio.rst
> +++ b/doc/guides/nics/virtio.rst
> @@ -41,8 +41,8 @@ The DPDK extends kni to support vhost raw socket
> interface,  which enables vhost to directly read/ write packets from/to a
> physical port.
>  With this enhancement, virtio could achieve quite promising performance.
> 
> -In future release, we will also make enhancement to vhost backend, -
> releasing peak performance of virtio PMD driver.
> +In future release, we will also make enhancement to vhost backend.
> +Peak performance of virtio PMD driver will be released with every release
> version since DPDK 17.02 release.

Hi,

There have been great performance improvements in Virtio in the last few
releases. However, we can't really promise that is will improve in every
release. I'd suggest removing these two lines and the previous line
starting with "With this enhancement, virtio could ...".


> 
>  ...
> 
> -*   RTE_PKTMBUF_HEADROOM should be defined larger than sizeof(struct
> virtio_net_hdr), which is 10 bytes.
> +*   RTE_PKTMBUF_HEADROOM should be defined
> +    larger than sizeof(struct virtio_net_hdr), which is 10 bytes, when
> using non-mergeable.
> +    larger than sizeof(struct virtio_net_hdr_mrg_rxbuf), which is 12
> bytes when mergeable or F_VERSION_1
> +    is set.
> 

All constants and struct names should be ```` quoted. Like this:


*   ``RTE_PKTMBUF_HEADROOM`` should be defined  larger than
    ``sizeof(struct virtio_net_hdr)``, which is 10 bytes, when using
    non-mergeable or larger than ``sizeof(struct virtio_net_hdr_mrg_rxbuf)``,
    which is 12 bytes when mergeable or ``F_VERSION_1`` is set.

John




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