devlink: Extend devlink rate API with traffic classes bandwidth management

Introduce support for specifying relative bandwidth shares between
traffic classes (TC) in the devlink-rate API. This new option allows
users to allocate bandwidth across multiple traffic classes in a
single command.

This feature provides a more granular control over traffic management,
especially for scenarios requiring Enhanced Transmission Selection.

Users can now define a relative bandwidth share for each traffic class.
For example, assigning share values of 20 to TC0 (TCP/UDP) and 80 to TC5
(RoCE) will result in TC0 receiving 20% and TC5 receiving 80% of the
total bandwidth. The actual percentage each class receives depends on
the ratio of its share value to the sum of all shares.

Example:
DEV=pci/0000:08:00.0

$ devlink port function rate add $DEV/vfs_group tx_share 10Gbit \
  tx_max 50Gbit tc-bw 0:20 1:0 2:0 3:0 4:0 5:80 6:0 7:0

$ devlink port function rate set $DEV/vfs_group \
  tc-bw 0:20 1:0 2:0 3:0 4:0 5:20 6:60 7:0

Example usage with ynl:

./tools/net/ynl/cli.py --spec Documentation/netlink/specs/devlink.yaml \
  --do rate-set --json '{
  "bus-name": "pci",
  "dev-name": "0000:08:00.0",
  "port-index": 1,
  "rate-tc-bws": [
    {"rate-tc-index": 0, "rate-tc-bw": 50},
    {"rate-tc-index": 1, "rate-tc-bw": 50},
    {"rate-tc-index": 2, "rate-tc-bw": 0},
    {"rate-tc-index": 3, "rate-tc-bw": 0},
    {"rate-tc-index": 4, "rate-tc-bw": 0},
    {"rate-tc-index": 5, "rate-tc-bw": 0},
    {"rate-tc-index": 6, "rate-tc-bw": 0},
    {"rate-tc-index": 7, "rate-tc-bw": 0}
  ]
}'

./tools/net/ynl/cli.py --spec Documentation/netlink/specs/devlink.yaml \
  --do rate-get --json '{
  "bus-name": "pci",
  "dev-name": "0000:08:00.0",
  "port-index": 1
}'

output for rate-get:
{'bus-name': 'pci',
 'dev-name': '0000:08:00.0',
 'port-index': 1,
 'rate-tc-bws': [{'rate-tc-bw': 50, 'rate-tc-index': 0},
                 {'rate-tc-bw': 50, 'rate-tc-index': 1},
                 {'rate-tc-bw': 0, 'rate-tc-index': 2},
                 {'rate-tc-bw': 0, 'rate-tc-index': 3},
                 {'rate-tc-bw': 0, 'rate-tc-index': 4},
                 {'rate-tc-bw': 0, 'rate-tc-index': 5},
                 {'rate-tc-bw': 0, 'rate-tc-index': 6},
                 {'rate-tc-bw': 0, 'rate-tc-index': 7}],
 'rate-tx-max': 0,
 'rate-tx-priority': 0,
 'rate-tx-share': 0,
 'rate-tx-weight': 0,
 'rate-type': 'leaf'}

Signed-off-by: Carolina Jubran <cjubran@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Mark Bloch <mbloch@nvidia.com>
Link: https://patch.msgid.link/20250629142138.361537-3-mbloch@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/Documentation/networking/devlink/devlink-port.rst b/Documentation/networking/devlink/devlink-port.rst
index 9d22d41a7cd1..5e397798a402 100644
--- a/Documentation/networking/devlink/devlink-port.rst
+++ b/Documentation/networking/devlink/devlink-port.rst
@@ -418,6 +418,14 @@ API allows to configure following rate object's parameters:
   to all node children limits. ``tx_max`` is an upper limit for children.
   ``tx_share`` is a total bandwidth distributed among children.
 
+``tc_bw``
+  Allow users to set the bandwidth allocation per traffic class on rate
+  objects. This enables fine-grained QoS configurations by assigning a relative
+  share value to each traffic class. The bandwidth is distributed in proportion
+  to the share value for each class, relative to the sum of all shares.
+  When applied to a non-leaf node, tc_bw determines how bandwidth is shared
+  among its child elements.
+
 ``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
 and arbitration among them is based on assigned weights.