[Bloat] Marvell 385

[Rosen Penev]

On Sat, Aug 25, 2018 at 9:29 PM Dave Taht <dave.taht at gmail.com> wrote:
>
> On Thu, Aug 23, 2018 at 8:32 AM 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.
>
> 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.
Yeah it's junk. While still developed, it has outstanding issues that
have not been fixed in a long time.

An example, monitor mode does not show data packets. Packet injection
still works though.
>
> 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 at swm.pp.se
> > _______________________________________________
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> > Bloat at lists.bufferbloat.net
> > https://lists.bufferbloat.net/listinfo/bloat
>
>
>
> --
>
> Dave Täht
> CEO, TekLibre, LLC
> http://www.teklibre.com
> Tel: 1-669-226-2619
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