[dpdk-dev] [PATCH 2/2] doc: update PMD options for mlx5
Yongseok Koh
yskoh at mellanox.com
Wed Mar 1 06:02:25 CET 2017
Enhanced multi-packet send mode is newly introduced for ConnectX-5 families
of adaptors.
Signed-off-by: Yongseok Koh <yskoh at 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
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