[Bloat] USB Ethernet Adapters with BQL?

[Jonathan Morton]

> On 17 Jun, 2016, at 22:42, Noah Causin <n0manletter at gmail.com> wrote:
> 
> I was looking into getting a USB 3.0 Gigabit Ethernet adapter, and I was trying to find ones that had BQL support in their drivers.
> 
> Are there any good ones out there, or is there something related to USB that reduces this feature's effectiveness?

Because the USB protocol gives greater decoupling between host and device than PCI (or PCIe) does, USB Ethernet adapters don’t have a general, explicit signal to indicate when packets are actually transmitted on the wire, or an easy low-latency way to discover the instantaneous buffer fill level (besides “full” vs. “not full”).  This makes implementing BQL challenging.

I’m not personally aware of any USB adapters with BQL.  That doesn’t mean there aren’t any.

 - Jonathan Morton