[PATCH net-next 10/10] net/mlx5: Document devlink rates and cross-esw scheduling

Tariq Toukan
2025-02-13T18:03:14Z

From: Cosmin Ratiu <cratiu@nvidia.com>

Extend the devlink-port documentation with a mention that parents can be
from different devices.

It seems rates were not documented in the mlx5-specific file, so add
examples on how to limit VFs and groups and also provide an example of
the intended way to achieve cross-esw scheduling.

Signed-off-by: Cosmin Ratiu <cratiu@nvidia.com>
Reviewed-by: Carolina Jubran <cjubran@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
---
.../networking/devlink/devlink-port.rst | 2 ++
Documentation/networking/devlink/mlx5.rst | 33 +++++++++++++++++++
2 files changed, 35 insertions(+)

diff --git a/Documentation/networking/devlink/devlink-port.rst b/Documentation/networking/devlink/devlink-port.rst
index 9d22d41a7cd1..1d9e5839eef4 100644
--- a/Documentation/networking/devlink/devlink-port.rst
+++ b/Documentation/networking/devlink/devlink-port.rst
@@ -417,6 +417,8 @@ API allows to configure following rate object's parameters:
Parent node name. Parent node rate limits are considered as additional limits
to all node children limits. ``tx_max`` is an upper limit for children.
``tx_share`` is a total bandwidth distributed among children.
+ If the device supports cross-function scheduling, the parent can be from a
+ different function of the same underlying device.

``tx_priority`` and ``tx_weight`` can be used simultaneously. In that case
nodes with the same priority form a WFQ subgroup in the sibling group
diff --git a/Documentation/networking/devlink/mlx5.rst b/Documentation/networking/devlink/mlx5.rst
index 7febe0aecd53..61e76da36faf 100644
--- a/Documentation/networking/devlink/mlx5.rst
+++ b/Documentation/networking/devlink/mlx5.rst
@@ -298,3 +298,36 @@ User commands examples:

.. note::
This command can run over all interfaces such as PF/VF and representor ports.
+
+Rates
+=====
+
+mlx5 devices can limit transmission of individual VFs or a group of them via
+the devlink-rate API in switchdev mode.
+
+User commands examples:
+
+- Print the existing rates::
+
+ $ devlink port function rate show
+
+- Set a max tx limit on traffic from VF0::
+
+ $ devlink port function rate set pci/0000:82:00.0/1 tx_max 10Gbit
+
+- Create a rate group with a max tx limit and adding two VFs to it::
+
+ $ devlink port function rate add pci/0000:82:00.0/group1 tx_max 10Gbit
+ $ devlink port function rate set pci/0000:82:00.0/1 parent group1
+ $ devlink port function rate set pci/0000:82:00.0/2 parent group1
+
+- Same scenario, with a min guarantee of 20% of the bandwidth for the first VFs::
+
+ $ devlink port function rate add pci/0000:82:00.0/group1 tx_max 10Gbit
+ $ devlink port function rate set pci/0000:82:00.0/1 parent group1 tx_share 2Gbit
+ $ devlink port function rate set pci/0000:82:00.0/2 parent group1
+
+- Cross-device scheduling::
+
+ $ devlink port function rate add pci/0000:82:00.0/group1 tx_max 10Gbit
+ $ devlink port function rate set pci/0000:82:00.1/32769 parent group1
--
2.45.0