[Bloat] Marvell 385

[Dave Taht <dave.taht@gmail.com>]

On Thu, Aug 23, 2018 at 8:32 AM Mikael Abrahamsson <swmike@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.

I just pulled two of those out of my junk drawer. (bricked presently).
It looks like we
can't apply fq_codel for wifi to it (big binary blob), still.

The firmware interface code is pretty clean though.

https://github.com/kaloz/mwlwifi

I rather liked the 385 chip myself, but wifi... can't fix, going back
in junk drawer
unless someone wants one.

The expressobin is a Marvell Armada "3700LP (88F3720) dual core ARM
Cortex A53 processor up to 1.2GHz" - how does that compare? I have
plenty of ath10k and ath9k pcmcia cards....

>
> >       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.
>
> 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.
>
> 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. 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).
>
> 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).
>
> --
> Mikael Abrahamsson    email: swmike@swm.pp.se
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-- 

Dave Täht
CEO, TekLibre, LLC
http://www.teklibre.com
Tel: 1-669-226-2619