[dpdk-dev] doc: add note for MAX QUEUES macro in vhost sample

  If the NIC has a queue number larger than 128, then we need to change
the ``MAX_QUEUES`` to a larger number to make sure we allocate a big
enough memory pool for device setup.

Signed-off-by: Xiao Wang <xiao.w.wang@intel.com>
---
 doc/guides/sample_app_ug/vhost.rst | 10 ++++++++++
 1 file changed, 10 insertions(+)
  

On 05/24/2018 08:11 AM, Xiao Wang wrote:
> If the NIC has a queue number larger than 128, then we need to change
> the ``MAX_QUEUES`` to a larger number to make sure we allocate a big
> enough memory pool for device setup.
> 
> Signed-off-by: Xiao Wang<xiao.w.wang@intel.com>
> ---
>   doc/guides/sample_app_ug/vhost.rst | 10 ++++++++++
>   1 file changed, 10 insertions(+)

Acked-by: Maxime Coquelin <maxime.coquelin@redhat.com>

Thanks,
Maxime
  

> If the NIC has a queue number larger than 128, then we need to change the
> ``MAX_QUEUES`` to a larger number to make sure we allocate a big enough
> memory pool for device setup.
> 
> Signed-off-by: Xiao Wang <xiao.w.wang@intel.com>
> ---
>  doc/guides/sample_app_ug/vhost.rst | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/doc/guides/sample_app_ug/vhost.rst
> b/doc/guides/sample_app_ug/vhost.rst
> index 5e7f24c4e..88905e404 100644
> --- a/doc/guides/sample_app_ug/vhost.rst
> +++ b/doc/guides/sample_app_ug/vhost.rst
> @@ -181,3 +181,13 @@ Common Issues
>  * Failed to build DPDK in VM
> 
>    Make sure "-cpu host" QEMU option is given.
> +
> +* Device start fails if NIC's max queues > the default number of 128
> +
> +  mbuf pool size is dependent on the MAX_QUEUES configuration, if NIC's
> + max queue number is larger than 128, device start will fail due to
> + insufficient mbuf.
> +
> +  Change the default number to make it work as below, just set the
> + number  according to the NIC's property.
> +      make EXTRA_CFLAGS="-DMAX_QUEUES=320"


Build fails: doc/guides/sample_app_ug/vhost.rst:193: WARNING: Unexpected indentation

Id suggest making it like below:

   Change the default number to make it work as below, just set the number
   according to the NIC's property. ::

       make EXTRA_CFLAGS="-DMAX_QUEUES=320"

You can add my ack when changes are made.

Marko K.

Acked-by: Marko Kovacevic <marko.kovacevic@intel.com>