[net-next Patch v9 6/6] docs: octeontx2: Add Documentation for QOS

From: Hariprasad Kelam
Date: Tue Apr 11 2023 - 05:05:57 EST


Add QOS example configuration along with tc-htb commands

Signed-off-by: Hariprasad Kelam <hkelam@xxxxxxxxxxx>
Reviewed-by: Simon Horman <simon.horman@xxxxxxxxxxxx>
---
.../ethernet/marvell/octeontx2.rst | 39 +++++++++++++++++++
1 file changed, 39 insertions(+)

diff --git a/Documentation/networking/device_drivers/ethernet/marvell/octeontx2.rst b/Documentation/networking/device_drivers/ethernet/marvell/octeontx2.rst
index 5ba9015336e2..eca4309964c8 100644
--- a/Documentation/networking/device_drivers/ethernet/marvell/octeontx2.rst
+++ b/Documentation/networking/device_drivers/ethernet/marvell/octeontx2.rst
@@ -13,6 +13,7 @@ Contents
- `Drivers`_
- `Basic packet flow`_
- `Devlink health reporters`_
+- `Quality of service`_

Overview
========
@@ -287,3 +288,41 @@ For example::
NIX_AF_ERR:
NIX Error Interrupt Reg : 64
Rx on unmapped PF_FUNC
+
+
+Quality of service
+==================
+
+octeontx2 silicon and CN10K transmit interface consists of five transmit levels starting from SMQ/MDQ, TL4 to TL1.
+The hardware uses the below algorithms depending on the priority of scheduler queues
+
+1. Strict Priority
+
+ - Once packets are submitted to MDQ, hardware picks all active MDQs having different priority
+ using strict priority.
+
+2. Round Robin
+
+ - Active MDQs having the same priority level are chosen using round robin.
+
+3. Each packet will traverse MDQ, TL4 to TL1 levels. Each level contains an array of queues to support scheduling and
+ shaping.
+
+4. once the user creates tc classes with different priority
+
+ - Driver configures schedulers allocated to the class with specified priority along with rate-limiting configuration.
+
+5. Enable HW TC offload on the interface::
+
+ # ethtool -K <interface> hw-tc-offload on
+
+6. Crate htb root::
+
+ # tc qdisc add dev <interface> clsact
+ # tc qdisc replace dev <interface> root handle 1: htb offload
+
+7. Create tc classes with different priorities::
+
+ # tc class add dev <interface> parent 1: classid 1:1 htb rate 10Gbit prio 1
+
+ # tc class add dev <interface> parent 1: classid 1:2 htb rate 10Gbit prio 7
--
2.17.1