Bug: [fast-reboot][Trixie] test_advanced_reboot.py::test_fast_reboot fails due to flooded packets number exceeds threshold (250)

[YairRaviv]

Is it platform specific

generic

Importance or Severity

Critical

Description of the bug

CPU consumption is heavier on Trixie, which already seems to impact fast-reboot performance on some systems, as described in this bug [Fast-reboot] Control plane time disruption is exceeds 90 seconds with Trixie.

Another result of this is test_advanced_reboot.py::test_fast_reboot failure due to the number of flooded packets being above 250.

Packets are being flooded in a small time window, between Vlan members are added to the point that the Vlan's RIF is ready, here is a comparison of these operations and timing before and after moving to Trixie:

Before Trixie:

1. First Vlan1000 member added - 15:30:55.260180 sonic NOTICE swss#orchagent: :- addVlanMember: Add member Ethernet0 to VLAN Vlan1000 vid:1000 pid1000000000017
2. Vlan1000 RIF created - 15:30:55.695734 sonic NOTICE syncd#SDK: [SAI_RIF.NOTICE] ... Created ROUTER_INTERFACE [OID:0x24100000006] [Type:DEFAULT, ID:9]

After Trixie:

1. First Vlan1000 member added - 14:07:11.603139 sonic NOTICE swss#orchagent: :- addVlanMember: Add member Ethernet114 to VLAN Vlan1000 vid:1000 pid1000000000048
2. Vlan1000 RIF created - 14:07:12.402659 sonic NOTICE syncd#SDK: [SAI_RIF.NOTICE] ... Created ROUTER_INTERFACE [OID:0x24100000006] [Type:DEFAULT, ID:9]

The diff is ~0.4 seconds, which results in ~550 flooded packets

Steps to Reproduce

Run platform_tests/test_advanced_reboot.py::test_fast_reboot on Trixie based SONiC

Actual Behavior and Expected Behavior

Actual:
FAILED:dut:Unexpected count of sent packets available in pcap file. Could be issue with DUT flooding for original packets which was sent to DUT, flooded count is: 566

Expected: Test should pass without errors

Relevant log output

Output of show version, show techsupport

Attach files (if any)

No response