multicast traffic is limited by Controller rx limit on helix 4 (accton as4610)

[KanjiMonster]

Expected Behavior

Multicast traffic is forwarded via hardware, and it is possible to achieve wire speed for multicast traffic.

Actual Behavior

Multicast traffic is forwarded via software, and is limited to ~10 Mbit/s.

Steps to Reproduce the Problem

1. Create a bridge, add two ports and allow traffic between these ports
2. Connect a device to one port, add an ip address to it, then start an iperf server (e.g. iperf -s -u -B 226.91.1.1%eno2 -i 1) on it
3. Connect a device to the other port, add an ip address from the same range to it, then start an iperf client (iperf -c 226.91.1.1 -B <ip address> -u -T 32 -t 3 -b 500M)

Specifications

• Version: BISDN Linux main / baseboxd 2.2.0
• Platform: AS44610
• Subsystem: nl_bridge

Initial Investigation

The issue are the ACL flows for multicast traffic that redirect all multicast traffic to the controller. When they are deleted, the expected throughput is reached.

[KanjiMonster]

More investigation shows this seems to be an issue for Helix 4, while Helix 5 is fine.

[KanjiMonster]

Trident 2 and Tomahawk+ are also fine, so this really seems to be a Helix 4 issue.