[Unicon-group] Unicon on RPi 2

[Jafar Al-G. <to....@gm...>]

Hello,

   If you every used the first generation RPi (all variants)  you know it
is slow. Running a graphical desktop was doable but it was a stretch
pushing the RPi to its limits. Building Unicon was painfully slow, but at
$35 I couldn't complain! :)

I received my second generation RPi 2 (still $35!) yesterday and I was
impressed! Not only it loads faster but it could also run a graphical
desktop without any hiccup. Very smooth experience. It truly could be used
as a desktop PC replacement for most tasks! The move from 0.7 Ghz ARMv6
single core with 512MB RAM  to 0.9 Ghz ARMv7 Quad Core with 1GB RAM makes a
huge difference.

I overclocked my old RPi when I first received to 1.0Ghz, improved a little
but it was still slow. I ran my own Unicon thread benchmark
(unicon/tests/thread/sum.icn) after changing the loop counter to 10^7 (10^8
takes a long time :) ) on the old and the new RPi's and here is what I got
(time in seconds ):

                            Overclocked RPi1         RPi2
single thread                    55                       24
4 threads                         N/A                       6

I did try one more thing on the new RPi2 that I didn't get a chance to do
on the old one which is to build Unicon with -O2 enabled and here is what I
got:

                           RPi2
single thread        12.4
4 threads              3.2

Optimization did make a huge difference for this little test. The Unicon
build process itself is a lot faster on RPi2 taking only a few minutes. If
you want a very cheap entry to Unicon on ARM now you have a new viable
option! And for those who don't know, we have a build configuration for ARM
(arm_32_linux). I also created a script that installs all of the tools and
dev libraries necessary to build Unicon on RPi in a single step. If anybody
is interested, I can pass it through an email, or I can put it in a public
place.

Cheers,
Jafar