Hi, Most DSA supported Broadcom switches have multiple queues per ports (usually 8) and each of these queues can be configured with different pause, drop, hysteresis thresholds and so on in order to make use of the switch's internal buffering scheme and have some queues achieve some kind of lossless behavior (e.g: LAN to LAN traffic for Q7 has a higher priority than LAN to WAN for Q0).
This is obviously very workload specific, so I'd want maximum programmability as much as possible. This brings me to a few questions: 1) If we have the DSA slave network devices currently flagged with IFF_NO_QUEUE becoming multi-queue (on TX) aware such that an application can control exactly which switch egress queue is used on a per-flow basis, would that be a problem (this is the dynamic selection of the TX queue)? 2) The conduit interface (CPU) port network interface has a congestion control scheme which requires each of its TX queues (32 or 16) to be statically mapped to each of the underlying switch port queues because the congestion/ HW needs to inspect the queue depths of the switch to accept/reject a packet at the CPU's TX ring level. Do we have a good way with tc to map a virtual/stacked device's queue(s) on-top of its physical/underlying device's queues (this is the static queue mapping necessary for congestion to work)? Let me know if you think this is the right approach or not. Thanks! -- Florian
