[dpdk-dev] doc: update multiple instance info for NULL crypto

  Add foot note & example to inform user how to use multiple instance.

Signed-off-by: Vipin Varghese <vipin.varghese@intel.com>
---
 doc/guides/cryptodevs/null.rst | 20 +++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)
  

Hi Vipin,

> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Vipin Varghese
> Sent: Monday, February 5, 2018 2:32 PM
> To: dev@dpdk.org; Kovacevic, Marko <marko.kovacevic@intel.com>
> Cc: Mcnamara, John <john.mcnamara@intel.com>; Varghese, Vipin
> <vipin.varghese@intel.com>
> Subject: [dpdk-dev] [PATCH] doc: update multiple instance info for NULL
> crypto
> 
> Add foot note & example to inform user how to use multiple instance.
> 
> Signed-off-by: Vipin Varghese <vipin.varghese@intel.com>
> ---
>  doc/guides/cryptodevs/null.rst | 20 +++++++++++++++++---
>  1 file changed, 17 insertions(+), 3 deletions(-)
> 
> diff --git a/doc/guides/cryptodevs/null.rst b/doc/guides/cryptodevs/null.rst
> index 03a3ddc..b7072b0 100644
> --- a/doc/guides/cryptodevs/null.rst
> +++ b/doc/guides/cryptodevs/null.rst
> @@ -41,6 +41,11 @@ each mbuf in the burst will be enqueued in an
> internal buffer for collection on  a dequeue call as long as the mbuf has a
> valid rte_mbuf_offload operation with  a valid rte_cryptodev_session or
> rte_crypto_xform chain of operations.
> 
> +.. Note::
> +
> +    In case of multiple instances of NULL cryptos, each instance should be of
> +    unique id.

I would use "NULL crypto PMDs".

> +
>  Features
>  --------
> 
> @@ -91,7 +96,16 @@ The following parameters (all optional) can be
> provided in the previous two call
> 
>  Example:
> 
> -.. code-block:: console
> +Single vdev instance::
> +
> +   ./l2fwd-crypto -l 1 -n 4 \
> +   --vdev="crypto_null,socket_id=0,max_nb_sessions=128" \
> +   -- -p 1 --cdev SW --chain CIPHER_ONLY --cipher_algo "null"
> +
> +Multiple vdev instance::

"instances".

> +
> +   ./l2fwd-crypto -l 1-2 -n 4 \
> +   --vdev="crypto_null_0,socket_id=0,max_nb_sessions=128" \
> +   --vdev="crypto_null_1,socket_id=1,max_nb_sessions=128" \
> +   -- -p 0x3 --cdev SW --chain CIPHER_HASH --cipher_algo null
> + --auth_algo null
> 
> -    ./l2fwd-crypto -l 1 -n 4 --
> vdev="crypto_null,socket_id=0,max_nb_sessions=128" \
> -    -- -p 1 --cdev SW --chain CIPHER_ONLY --cipher_algo "null"
> --
> 1.9.1

This looks good to me, but I think this can be extended to other PMDs, not just NULL crypto.
Could you send another version, changing the other guides (for the SW based drivers)?

Thanks,
Pablo