[Radiance-general] Radiance on Raspberry Pi

[Mark Stock]

For those interested, I built Radiance on a Raspberry Pi yesterday
(700 MHz single-core ARMv6, 3.5W, 512 MB RAM) and ran the speed test
from http://markjstock.org/pages/rad_bench.html.

The results are not encouraging, but you don't buy a Raspberry Pi for
speed. It took 17 hours to finish the rpict portion of the test. The
best serial time ever recorded was just under 18 minutes on an Intel
i7-2600K from 1.5 years ago (57x faster). The peak SMP time is 3.5
minutes, recorded earlier this year (296x faster). The Raspberry Pi's
time was similar to what we would expect from computers from 2001-2: a
Pentium II at about 250MHz, or a 400HMz Sun UltraSparc, both which
regularly sported about 512MB of RAM, but obviously cost about 100x
more.

100 Raspberry Pi machines, networked and working in parallel, would
consume 350W and cost $3500 (not counting networking hardware), both
numbers in the ballpark of the best current CPU-intensive
single-workstation systems. Assuming perfect parallelization, it could
finish in a little over 10 minutes, but a more realistic guess would
be 15-20 minutes. I'm glad NREL decided to go with the Xeon Phi
instead of a cluster of RPis.

Maybe I should start a Radiance "speed" test that measures the results
in Joules instead of seconds.

Mark