[Bloat] UniFi Dream Machine Pro

[Jonathan Morton]

> On 22 Jan, 2021, at 11:09 pm, Toke Høiland-Jørgensen via Bloat <bloat at lists.bufferbloat.net> wrote:
> 
> As Sebastian says, the source of lower performance when using SQM on
> some boxes is the traffic shaper, and sometimes the lack of hardware
> offloads.

I have a strong suspicion that on some hardware, the offload engine & switch is connected to the SoC through a link that is much slower than the Ethernet ports exposed to the outside.  As long as traffic stays within the engine, it can run at line rate, but engaging rich software measures requires stuffing it all through the narrower link.  This is independent of the CPU's capabilities and is purely an I/O bottleneck.

In this particular case, I believe the router portion of the Dream Machine is natively a Gigabit Ethernet device, for which good IPsec and SQM performance at 800Mbps is reasonably expected.  The pair of 10G ports are part of the switch portion, and thus intended to support LAN rather than WAN traffic.  Think of it as equivalent to attaching a Raspberry Pi 4 (which has native GigE) to a switch with a pair of 10G "uplink" ports for daisy-chaining to other switches.

 - Jonathan Morton