[Bloat] [Cerowrt-devel] beating the drum for BQL

[Sebastian Moeller]

Dear Mikael,


> On Aug 24, 2018, at 00:32, Mikael Abrahamsson <swmike at swm.pp.se> wrote:
> 
> On Thu, 23 Aug 2018, Sebastian Moeller wrote:
> 
>> router should be able to handle at least the sold plan's bandwidth with its main CPU...)
> 
> There is exactly one SoC on the market that does this, and that's Marvell Armada 385, and it hasn't been very successful when it comes to ending up in these kinds of devices. It's mostly ended up in NASes and devices such as WRT1200AC, WRT1900ACS, WRT3200AC.

	Intersting question, how will the intel grx750 perform (https://www.intel.com/content/www/us/en/smart-home/connected-home/anywan-grx750-home-gateway-brief.html) after all that is a SoC with a dual core atom CPU with up to 2.5 GHz frequency?

> 
>> 	Sure doing less/ a half asses job is less costly than doing it right, but in the extreme not doing the job at all saves even more energy ;). And I am not sure we are barking up the right tree here, it is not that all home CPE are rigorously optimized for low power and energy saving... my gut feeling is that the only optimizing principle is cost for the manufacturer/OEM and that causes underpowered CPU that are packet-accerlerated"-doped to appear to be able to do their job. I might be wrong though, as I have ISP internal numbers on this issue.
> 
> The CPU power and RAM/flash has crept up a lot in the past 5 years because other requirements in having the HGW support other applications than just being a very simple NAT44+wifi router.

	That matches my observation as well, people seem to want to concentrate more functionality at the one device that needs to run 24/7 instead of using multiple independent devices (and I do not want to blame them, even though I believe from a robustness perspective it would be better to not concentrate everything in the routing/firewall device).

> 
> Cost is definitely an optimization, and when you're expected to have a price-to-customer including software in the 20-40 EUR/device range, then the SoC can't cost much. There has also been a lot of vendor lock-in.

	Sure, but my ISP charged 4 EUR per month for the DSL-router that adds up to 12*2*4 = 96 EUR over the 2 years contract duration and to 12*5*4 = 240 over my renting duration; assuming that my ISP does not need to make a profit on this device (after all I am renting this to be able to consume internet and telephone from them) that is considerably more that 20-40 EUR. This is especially farcical since until a few years ago the dsl-routers have been given for "free" and when they switched to mandatory renting the baseplan price was not reduced by the same amount. I guess what I want to convey is while cost is imprtant it is not a goo d excuse to distribute underpowered devices....

> 
> But now speeds are creeping up even more, we're now seeing 2.5GE and 10GE platforms, which require substantial CPU power to do forwarding.

	Well, it is all swell if a router delivers 2.5/5/10 Gbps on the LAN side, but a) I know only few households that would profit from that and b) at that speeds short-comings of a router become even more obvious and c) bandplans to actually feed such a beast from the wan side seem expensive enough that the customer should also be able to pay for a competent router (one can get intel based multicore atom boards at the same price point as the high-end homerouters at ~250EUR).

> The Linux kernel is now becoming the bottleneck in the forwarding, not even on a 3GHz Intel CPU is it possible to forward even 10GE using the normal Linux kernel path (my guess right now is that this is due to context switching etc, not really CPU performance).

	That is a bridge to cross once we reach it, I doubt that we will realistically reach 10 Gbps home internet access for the masses soon.

> 
> Marvell has been the only one to really aim for lots of CPU performance in their SoC, there might be others now going the same path but it's also a downside if the CPU becomes bogged down with packet forwarding when it's also expected to perform other tasks on behalf of the user (and ISP).

	As stated above there is an argument to concentrate non core router functionality to another device (like one of those NAS devices that can also share a printer)

All that said, I believe that your opinion is far closer to the real world and positions of the ISPs, so I expect things stay as they are, but I cab dream can't I ;) ...


Best Regards
	Sebastian

> 
> -- 
> Mikael Abrahamsson    email: swmike at swm.pp.se