[OT] ARMs (was: ARM series Lua implementation?)

[David Given <dg@...>]

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dcharno wrote:
[...]
> Off topic, but what do you think about the SheevaPlug.  It looks
> interesting.

Well, I run my entire house system off one. It serves cowlark.com, does
all my incoming and outgoing email, spam filtering, is my main ssh
point-of-contact, manages all my backups, runs the Java backend for the
website comment system etc. The whole stack including SheevaPlug, home
made 64GB SSD, ADSL router, wireless router, UPS, and a bunch of USB
hubs runs at about 30 watts, going up to 40 when it spins up the
external hard drive. It runs Debian.

It's not entirely perfect --- it's got exactly one USB 2.0 port, which
means that my home made RAID array of USB keys is pushing bandwidth
limits almost continuously; there's something slightly dodgy in the
Linux kernel that causes it to kill processes under load; the Marvell
USB chipset is notoriously quirky that causes I/O errors with some
devices. OTOH it is $99, which I can forgive a lot for. Marvell are
producing a different version, the OpenRD, which has got a lot more
ports (including eSATA) and is more suitable for server use, but it's
three times the price.

The Marvell chipset is apparently based on the old StrongARM
architecture that Intel used to have; this could be the reason for their
cool relationship with ARM, as Intel and ARM aren't talking to each
other these days. The StrongARM architecture has a reputation for being
fast but hot. The thing certainly gets warm when in use. At 1.2GHz it's
pretty high-end as ARMs go but I believe the new Cortex line (from ARM)
will beat it.

I have a writeup here with some benchmarks from about a week after I got
it. It's now a bit obsolete and a few things are wrong --- I should post
an update.

http://www.cowlark.com/2009-04-15-sheevaplug/

(Yes, hosted on the SheevaPlug.)

Lua-wise, I have no complaints on it --- although as it has no FPU if I
were doing anything performance-related I'd probably want to build a
copy with LNUM. The entire website is based on a home-made CMS written
in Lua, which compiles the templates into static HTML. On the SheevaPlug
itself, it takes 15-20 seconds to rebuild the site depending whether
email comes in while it's working. That's with Debian's stock Lua. On my
Celeron-D desktop it takes about 3.

The Lua executable is 129kB of code, while on i386 it's 140kB, showing
that ARM is denser than i386. I haven't build a Thumb version (which the
SheevaPlug also supports), but it might be interesting.

This is the kind of device that an integerised ARM LuaJIT would be
really rather good on.

- --
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