devlink shows the shared buffer's pools but no port's share of them. A
switch port's ingress is one buffer manager port, port + 7 as qca-ssdk's
PHY_PORT_TO_BM_PORT() has it, so its single ingress class binds to that
port's buffer group and its threshold is the dynamic weight. The egress
classes are the port's unicast queues and report their admission group and
weight, and moving them is refused because the driver assigns the queue
groups. Occupancy is read from the buffer and queue counters at each
snapshot; they report only the current value, so the maximum is the
largest value a snapshot has seen.
On IPQ8074 a port threshold changes only the weight of that BM port's
entry, the neighbouring port's entry stays intact, an egress bind is
refused, and a port shaped to 50 Mbit/s with a 200000-byte limit reports
87040 bytes occupied in its egress pool under load.
Assisted-by: Claude:claude-opus-5-5
Signed-off-by: Julius Bairaktaris <julius@bairaktaris.de>
Link: https://github.com/openwrt/openwrt/pull/25700
Signed-off-by: Robert Marko <robimarko@gmail.com>
Julius Bairaktaris
5b835fbcd8