Raspberry Pi server clusters

Hooray,  objective measurements are starting to appear as more people receive their Pi boards:

• http://candgsoc.host56.com/2012/04/quality-time-with-a-raspberry-pi/

It's very important to match what the board can offer against the specific requirements of your application, otherwise it can lead to disappointment.  Also, it's crucial not to make a one-dimensional analysis when multiple factors come into play, as cand's article highlights --->  the Pi's Ethernet performance can approach the full bandwidth of the line, but only at a huge CPU cost.

First indications then suggest that networked applications of Pi are likely to be most successful when the network use is occasional and when not much else has to be executed concurrently with the communications.

This will need a lot more careful analysis so that we know exactly where the bottlenecks are.  Some of them are quite likely to be remedied by kernel config improvements or with better drivers, but one has to know the detailed cause of a problem before one can tackle it.

Morgaine.

The following is about HPC which isn't my focus, but interesting nevertheless.  From Slashdot today:

"Phoronix constructed a low-cost, low-power 12-core ARM cluster running Ubuntu 12.04 LTS and made out of six PandaBoard ES OMAP4460 dual-core ARMv7 Cortex A9 chips. Their results show the ARM hardware is able to outperform Intel Atom and AMD Fusion processors in performance-per-Watt, except it sharply loses out to the latest-generation Intel Ivy Bridge processors."

More at:  http://linux.slashdot.org/story/12/06/16/1510257/12-core-arm-cluster-beats-intel-atom-amd-fusion

Morgaine.

Probably not quite what you're thinking of but the Design Spark forum (the competition) has an article on someone using Pis to make a VAX cluster.

Colin

OMG, DECnet!  http://www.designspark.com/content/raspberry-pi-vax-cluster

Thanks for the headsup, Colin.

There is an interesting article benchmarking a 12-core ARMv7 cluster

against some PC's.

http://www.phoronix.com/scan.php?page=article&item=phoronix_effimass_cluster&num=1

Yeah, saw that.  It's very underwhelming though.  I'm a bit surprised that ARM (the company) isn't working harder in that area and dedicating more research to multicore clustering.  A reference board from them bearing say 16 dual-core Cortex-A9 MPcore chips would really fan the flames wonderfully.

Intel can still warrant its total complacency about server-side ARM because a modern Atom core is nearly an order of magnitude faster than the best ARM core, so it doesn't have to push very strongly.  Well ARM can't do anything about the speed difference yet, but because it has the power advantage over Atom it really ought to use that to promote high core counts in clusters and start closing the gap with sheer core numbers.  It's not doing that, and I'm not too sure why not.

Morgaine.

There must be better ARM chips in the pipeline. At least Dell & HP are said to have arm based servers in the works and I can't see them being the only ones. Better performance per watt for arm only goes so far. I can see it being a tough sell if you need 10x the number of servers to meet some performance point.

There must be better ARM chips in the pipeline. At least Dell & HP are said to have arm based servers in the works and I can't see them being the only ones. Better performance per watt for arm only goes so far. I can see it being a tough sell if you need 10x the number of servers to meet some performance point.