[SmartSwitch] [Nvidia] Remove PG 3 and 4 for Internal Ports

[oleksandrivantsiv]

Why I did it

PG's 3 & 4 for Internal ports today have lossy buffer profiles attached, but this is redundant and can be removed as they occupy extra overhead even though it's not significant

Work item tracking

• Microsoft ADO (number only):

How I did it

Make the cable length for Dpc ports to 0m and create a new TC_PG_MAP for internal ports

How to verify it

Run config qos reload --no-dynamic-buffer, config save -y and config reload -y

redis-cli -n 4 hget "CABLE_LENGTH|AZURE" Ethernet224
"0m"
redis-cli -n 4 hget "PORT_QOS_MAP|Ethernet232" tc_to_pg_map
"AZURE_DPC"

root@r-bobcat-01:/home/admin# sonic-db-cli CONFIG_DB HGETALL "TC_TO_PRIORITY_GROUP_MAP|AZURE_DPC"
{'0': '0', '1': '0', '2': '0', '3': '0', '4': '0', '5': '0', '6': '0', '7': '7'}

redis-cli -n 0 keys "BUFFER_PG*Ethernet232*"
1) "BUFFER_PG_TABLE:Ethernet232:0"

redis-cli -n 0 keys "BUFFER_PG*Ethernet88*"
1) "BUFFER_PG_TABLE:Ethernet88:3-4"
2) "BUFFER_PG_TABLE:Ethernet88:0"

2025 Feb 14 11:36:15.333024 sonic NOTICE swss#buffermgrd: :- doSpeedUpdateTask: Not creating/updating PG profile for port Ethernet224. Cable length is set to 0m
2025 Feb 14 11:36:15.333024 sonic NOTICE swss#buffermgrd: :- doSpeedUpdateTask: Not creating/updating PG profile for port Ethernet232. Cable length is set to 0m
2025 Feb 14 11:36:15.333142 sonic NOTICE swss#buffermgrd: :- doSpeedUpdateTask: Not creating/updating PG profile for port Ethernet240. Cable length is set to 0m
2025 Feb 14 11:36:15.333142 sonic NOTICE swss#buffermgrd: :- doSpeedUpdateTask: Not creating/updating PG profile for port Ethernet248. Cable length is set to 0m

Which release branch to backport (provide reason below if selected)

• 201811
• 201911
• 202006
• 202012
• 202106
• 202111
• 202205
• 202211
• 202305

Tested branch (Please provide the tested image version)

Description for the changelog

Link to config_db schema for YANG module changes

A picture of a cute animal (not mandatory but encouraged)

[mssonicbld]

/azp run Azure.sonic-buildimage

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[kperumalbfn]

@oleksandrivantsiv Could you check if WRED is applied on these internal ports? I believe thats also not required.

[prabhataravind]

lgtm. I recall some qos tests were not passing before. Could you please make sure qos/test_buffer.py passes with this change?