doc: inline data settings affect mlx5 Tx queue max size
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Commit Message
Introduces the possible limitations on maximal Tx queue
size in descriptors if Tx inline data are enabled.
Signed-off-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
---
doc/guides/nics/mlx5.rst | 10 ++++++++++
1 file changed, 10 insertions(+)
Comments
08/08/2019 13:47, Viacheslav Ovsiienko:
> Introduces the possible limitations on maximal Tx queue
> size in descriptors if Tx inline data are enabled.
>
> Signed-off-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
Applied, thanks
@@ -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`` devarg 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