Enhanced multi-packet send mode is newly introduced for ConnectX-5 families of adaptors.
Signed-off-by: Yongseok Koh <ys...@mellanox.com> --- doc/guides/nics/mlx5.rst | 32 ++++++++++++++++++++++++++++---- 1 file changed, 28 insertions(+), 4 deletions(-) diff --git a/doc/guides/nics/mlx5.rst b/doc/guides/nics/mlx5.rst index 09922a08f..fda8bc3fe 100644 --- a/doc/guides/nics/mlx5.rst +++ b/doc/guides/nics/mlx5.rst @@ -181,14 +181,38 @@ 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. 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 unused space 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. + Prerequisites ------------- -- 2.11.0
