[Bloat] Other CAKE territory (was: CAKE in openwrt high CPU)

[Jonathan Morton]

> On 4 Sep, 2020, at 1:14 am, David Collier-Brown <davecb.42 at gmail.com> wrote:
> 
> I'm wondering if edge servers with 1Gb NICs are inside the "CAKE stays relevant" territory?  

Edge servers usually have strong enough CPUs and I/O - by which I mean anything from AMD K8 and Intel Core 2 onwards with PCIe attached NICs - to run Cake at 1Gbps without needing special measures.  I should run a test to see how much I can shove through an AMD Bobcat these days - not exactly a speed demon.

We're usually seeing problems with the smaller-scale CPUs found in CPE SoCs, which are very much geared to take advantage of hardware accelerated packet forwarding.  I think in some cases there might actually be insufficient internal I/O bandwidth to get 1Gbps out of the NIC, into the CPU, and back out to the NIC again, only through the dedicated forwarding path.  That could manifest itself as a lot of kernel time spent waiting for the hardware, and can only really be solved by redesigning the hardware.

 - Jonathan Morton