[cherry-pick] [202012] Update qos config to clear queues for bounced back traffic

[bingwang-ms]

This PR is to cherry-pick #10176 and #10565 to 202012 branch after resolving conflicts.

Signed-off-by: bingwang wang.bing@microsoft.com

Why I did it

This PR is to redefine DSCP_TO_DC_MAP , TC_TO_QUEUE_MAP and TC_TO_PRIORITY_GROUP_MAP table to clear queue 2 and queue 6 for bounced back traffic.
To support the extra lossless queue 2 and 6, the table pfc_enable, pfcwd_sw_enable and SCHEDULER are also updated in the template.

HLD sonic-net/SONiC#950

SKU includes

• Arista-7050CX3-32S-C32
• Arista-7050CX3-32S-D48C8
• Arista-7260CX3-D108C8
• Arista-7260CX3-C64
• Arista-7260CX3-Q64

Changed table:

• DSCP_TO_TC_MAP

Original	Leaf	Dual-ToR	Why do this change
"2" : "1"	"2" : "2"	"2" : "1"	Only change for leaf router to map DSCP 2 to TC 2 as TC 2 will be used for lossless TC
"5" : "2"	"5" : "1"	"5" : "1"	To clear TC 2 for bounced back traffic
"6" : "1"	"6" : "6"	"6" : "1"	Only change for leaf router to map DSCP 6 to TC 6 as TC 6 will be used for lossless TC
"33" : "1"	"33" : "1"	"33" : "2"	Only change for Tor router. To map DSCP33->TC 2 as we need to conserve DSCP 33 for bounced back traffic. The tunnel level map will map TC 2 -> DSCP 33
"48" : "6"	"48" : "7"	"48" : "7"	To clear TC 6 for bounced back traffic

• TC_TO_PRIORITY_GROUP_MAP

Original	Leaf	Dual-ToR	Why do this change
"2" : "0"	"2" : "2"	"2" : "0"	Only change for leaf router to map TC 2 to PG 2 as PG 2 will be used for lossless PG
"6" : "0"	"6" : "6"	"6" : "0"	Only change for leaf router to map TC 6 to PG 6 as PG 6 will be used for lossless PG

• TC_TO_QUEUE_MAP

Original	Leaf	Dual-ToR	Why do this change
"2" : "2"	"2" : "2"	"2" : "1"	Only change for ToR router to map TC 2 to Queue 1. As we mapped DSCP33->TC2 on ToR router, we need to remap TC2 to a lossy queue

How I did it

Define a macro for SKUs that requires remapping.

How to verify it

1. Verified by rendering the J2 template with sonic-cfggen.
2. Verified by UT.

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

• 201811
• 201911
• 202006
• 202012
• 202106
• 202111

Description for the changelog

Update qos config to clear queues for bounced back traffic.

Link to config_db schema for YANG module changes

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

[lguohan]

is there enable and disable flag?

[stephenxs]

Now that there are 4 lossless queues on the ports connecting T1 and dual ToR on the egress side while 2 lossless queues on the rest ports, is there a logic to update the BUFFER_QUEUE table? For some vendor, if not all, lossless/lossy traffic requires different buffer pool and profile on the egress side.
Typically, such logic is in the buffer template on a per-device basis. However, we need to pass port_names_list_extra_queues as an argument to indicate 4 / 2 lossless queues should be applied on which ports respectively.

[bingwang-ms]

is there enable and disable flag?

Yes, there will be a flag to turn on/off the feature. Please review HLD sonic-net/SONiC#982

[bingwang-ms]

I don't think the change will impact T2 or above. There are 4 lossless queues in ports between T1 and ToR.

[stephenxs]

I don't think the change will impact T2 or above. There are 4 lossless queues in ports between T1 and ToR.

Typo. it should be T1 and ToR. I updated the original comment

[bingwang-ms]

I don't think the change will impact T2 or above. There are 4 lossless queues in ports between T1 and ToR.

Typo. it should be T1 and ToR. I updated the original comment

Thanks. We already have a PR to update BUFFER_QUEUE table. Please see #10496 Thanks

[bingwang-ms]

/azp run

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[stephenxs]

@bingwang-ms can you resolve the conflict and retrigger the build? thanks.

[bingwang-ms]

@bingwang-ms can you resolve the conflict and retrigger the build? thanks.

Thanks. All fixed.

[bingwang-ms]

Please hold on merging this PR until the FLAG is available to turn off the feature.