feat(interface): apply MTU for dpdk plugin ifaces

When changing MTU on a running VPP, the interface has to be down.

- Other plugins (rdma, avf, af_xdp) need vastly different logic,
  so support for them will be added later.
+ Mlx5-core does not need to set MTU on Linux interface.
+ MTU setting now does not happen at final setting path up,
  it happens in driver initialization layer instead
  E.g. AVF tests will not attempt to change MTU.
+ MTU edit removed from some non-hardware interfaces (including memif)
  e.g. bond interfaces. MTU on parent hw interface seems to be enough.
+ The non-jumbo MTU value used is 1800,
  so 1518B tests with additional encapsulation can still work.
+ When VPP MTU setting fails, the failure is now propagated.
  Previously, the failure was just logged and ignored,
  but now there is no reason to hide it.

Ticket: CSIT-1797

Change-Id: I3b853f1faf90001d544cbbb87b2affbb882ffba0
Signed-off-by: Vratko Polak <vrpolak@cisco.com>

1 files changed, 10 insertions, 3 deletions

diff --git a/resources/libraries/robot/performance/performance_vars.robot b/resources/libraries/robot/performance/performance_vars.robot
index 0721634f71..a0fa277e4c 100644
--- a/resources/libraries/robot/performance/performance_vars.robot
+++ b/resources/libraries/robot/performance/performance_vars.robot
@@ -1,4 +1,4 @@
-# Copyright (c) 2022 Cisco and/or its affiliates.
+# Copyright (c) 2023 Cisco and/or its affiliates.
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at:
@@ -404,6 +404,8 @@
 | | ... | *Test variables set:*
 | | ... | - jumbo - Jumbo boolean, true if jumbo packet support has to be
 | | ... | enabled. Type: boolean
+| | ... | - recommended_mtu - Resonable value (with space for encap overhead)
+| | ... | according to jumbo. Type: int
 | |
 | | ... | *Example:*
 | |
@@ -413,11 +415,14 @@
 | | Set Numeric Frame Sizes
 | | ${jumbo} = | Evaluate | ${max_frame_size} >= 1522
 | | Set Test Variable | \${jumbo}
+| | ${recommended_mtu} = | Set Variable If | ${jumbo} | ${9200} | ${1800}
+| | Set Test Variable | \${recommended_mtu}
 
 | Set Max Rate And Jumbo
 | | [Documentation]
-| | ... | This keyword computes maximal unidirectional transmit rate
-| | ... | and jumbo boolean (some suites need that for configuration decisions).
+| | ... | This keyword computes maximal unidirectional transmit rate,
+| | ... | jumbo boolean (some suites need that for configuration decisions),
+| | ... | and recommended MTU value (depends on jumbo).
 | | ... | To streamline suite autogeneration, both input and output values
 | | ... | are communicated as test (or broader scope) variables,
 | | ... | instead of explicit arguments and return values.
@@ -447,6 +452,8 @@
 | | ... | Type: float
 | | ... | - jumbo - Jumbo boolean, true if jumbo packet support has to be
 | | ... | enabled. Type: boolean
+| | ... | - recommended_mtu - Resonable value (with space for encap overhead)
+| | ... | according to jumbo. Type: int
 | | ... | - max_frame_size - Maximal frame size including overhead. Type: float
 | | ... | - avg_directional_frame_size - Average frame size including overhead
 | | ... | for the more loaded direction. Type: float