Re: [PATCH v2 2/2] doc: update PMD options for mlx5

[Shahaf Shuler <shahafs@mellanox.com>]

Saturday, March 11, 2017 1:14 AM, Yongseok Koh:
> Enhanced multi-packet send mode is newly introduced for ConnectX-5
> families of adaptors.
> 
> Signed-off-by: Yongseok Koh <yskoh@mellanox.com>
> ---
>  doc/guides/nics/mlx5.rst | 31 +++++++++++++++++++++++++++----
>  1 file changed, 27 insertions(+), 4 deletions(-)
> 
> diff --git a/doc/guides/nics/mlx5.rst b/doc/guides/nics/mlx5.rst index
> 41f3a472e..0783aebdd 100644
> --- a/doc/guides/nics/mlx5.rst
> +++ b/doc/guides/nics/mlx5.rst
> @@ -183,10 +183,17 @@ Run-time configuration
> 
>  - ``txq_mpw_en`` parameter [int]
> 
> -  A nonzero value enables multi-packet send. This feature allows the TX
> -  burst function to pack up to five packets in two descriptors in order to
> -  save PCI bandwidth and improve performance at the cost of a slightly
> -  higher CPU usage.
> +  A nonzero value enables multi-packet send (MPS) for ConnectX-4 Lx and
> + enhanced multi-packet send (Enhanced MPS) for ConnectX-5. MPS allows
> + the  TX burst function to pack up multiple packets in a single
> + descriptor  session in order to save PCI bandwidth and improve
> + performance at the  cost of a slightly higher CPU usage. When
> + ``txq_inline`` is set along  with ``txq_mpw_en``, TX burst function
> + tries to copy entire packet data  on to TX descriptor instead of
> + including pointer of packet only if there  is enough room remained in
> + the descriptor. ``txq_inline`` sets  per-descriptor space for either
> + pointers or inlined packets. In addition,  Enhanced MPS supports
> + hybrid mode - mixing inlined packets and pointers  in the same descriptor.
> 
>    This option cannot be used in conjunction with ``tso`` below. When ``tso``
>    is set, ``txq_mpw_en`` is disabled.
> @@ -194,6 +201,22 @@ Run-time configuration
>    It is currently only supported on the ConnectX-4 Lx and ConnectX-5
>    families of adapters. Enabled by default.
> 
> +- ``txq_mpw_hdr_dseg_en`` parameter [int]
> +
> +  A nonzero value enables including two pointers in the first block of
> + TX  descriptor. This can be used to lessen CPU load for memory copy.
> +
> +  Effective only when Enhanced MPS is supported. Disabled by default.
> +
> +- ``txq_max_inline_len`` parameter [int]
> +
> +  Maximum size of packet to be inlined. This limits the size of packet
> + to  be inlined. If the size of a packet is larger than configured
> + value, the  packet isn't inlined even though there's enough space
> + remained in the  descriptor. Instead, the packet is included with pointer.
> +
> +  Effective only when Enhanced MPS is supported. The default value is 256.
> +
>  - ``tso`` parameter [int]
> 
>    A nonzero value enables hardware TSO.
> --

Acked-by: Shahaf Shuler <shahafs@mellanox.com>

> 2.11.0