From 3a418d1d3d8561c1de4bfc7c05fc4c975aa1a0b1 Mon Sep 17 00:00:00 2001 From: Viacheslav Ovsiienko Date: Thu, 8 Aug 2019 11:47:23 +0000 Subject: [PATCH] doc: add limitation with mlx5 Tx inline settings Introduces the possible limitations on maximal Tx queue size in descriptors if Tx inline data are enabled. Signed-off-by: Viacheslav Ovsiienko --- doc/guides/nics/mlx5.rst | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/doc/guides/nics/mlx5.rst b/doc/guides/nics/mlx5.rst index d6082ac4d3..411552037e 100644 --- a/doc/guides/nics/mlx5.rst +++ b/doc/guides/nics/mlx5.rst @@ -162,6 +162,12 @@ Limitations To receive IPv6 Multicast messages on VM, explicitly set the relevant MAC address using rte_eth_dev_mac_addr_add() API. +- The amount of descriptors in Tx queue may be limited by data inline settings. + Inline data require the more descriptor building blocks and overall block + amount may exceed the hardware supported limits. The application should + reduce the requested Tx size or adjust data inline settings with + ``txq_inline_max`` and ``txq_inline_mpw`` devargs keys. + - E-Switch decapsulation Flow: - can be applied to PF port only. @@ -400,6 +406,10 @@ Run-time configuration option should be used with care, as it may lower performance when back pressure is not expected. + If inline data are enabled it may affect the maximal size of Tx queue in + descriptors because the inline data increase the descriptor size and + queue size limits supported by hardware may be exceeded. + - ``txq_inline_min`` parameter [int] Minimal amount of data to be inlined into WQE during Tx operations. NICs -- 2.20.1