[Battlemesh] OT: Badly balanced devices [was: What hardware still works?]

[Daniel Golle]

On Wed, Feb 24, 2016 at 07:10:40PM +0100, Juliusz Chroboczek wrote:
> >> A dual-band 802.11ac device with only 100Mbit Ethernet? Non merci.
> 
> > Some glinet models advertise 300mbps radio side with a 100mbps ethernet side.
> 
> Well, 300Mbps is at most 120Mbps above the MAC, so that's not *that*
> shocking, but still, I'd really expect to get two independent GBE NICs on
> any recent device.
> 
> The other issue with these devices is the SoC -- the CPU core is a 500MHz
> MIPS 24Kec, which is a very reasonable CPU (1.6 DMIPS/MHz), but the
> systems that I've examined have rather disappointing memory bandwidth --
> I'd be suprised if it could push more than 300MBps or so.
> 
> I need to put some time aside to look at some cheap ARM boards.  The
> hardware is more open (specs are more readily available), the ecosystem is
> richer, and the memory/cache subsystem seems more refined to my untrained
> eyes.  But the architecture is less elegant than MIPS, so I'm feeling some
> internal resistance.

The only ARM SoCs with PCIe I know are Marvel Armada (ie. the successor
of the kirkwood, most of you probably know from the Sheevaplug) and
Qualcomm's IPQ (basically a Snapdragon without the GPU). I've never
touched the IPQ because I consider it the "mother of lockdowns",
secure-boot by default, just like on smartphones.
I did evaluate Marvel's Armada SoC and it has nice performance, but
all devices I could find in the wild also come with Marvel's wifi,
which is a FullMAC (like Intel's iwlwifi) and I've had so much trouble
with that kind of design in the past in which I couldn't help myself,
I decided to avoid it.

Most of MediaTek's high-end MIPS SoCs allow the board manufacturers to
choose anything from the slowest DDR2 and up to 1GHz DDR3. So better
boards with the same SoC might perform way better, because they gave it
some decent RAM.

I was very impressed by those MT7621 boards having fast DDR3, it's a
dual-core MIPS1004Kc, each with 2 threads (like HT on Intel's CPUs),
2x GMAC, built-in gigabit switch, USB 3.0 and 3x PCIe to connect WiFi
chips...