Preliminary tests

In our project we have to use a parallel algorithm which implements integer computing. Meanwhile the implementation of this algorithm for ARM architecture, we explored two other benchmarks (Nbench and Dhrystone) that provide a measure of integer performance in two operating systems (Rasbian and Fidora).

We notice that Fidora 21 isn't an official final release version of Fedora for Raspberry PI 2 but just a third distribution compiled for ARMv7. But it contains some limitations which aren't permitted us to test Nbench in this OS.

For this reason we present the results of Nbench testing from Rasbian OS that can be compared to other results from following link here:

The results of Dhrystone benchmark for Rasbian OS are shown below.

And those for Fidora OS are

So these results could be compared to other results from the link here.
We can see from our tests that there is an advantage of Fidora OS which can be explain by reduced of active background modules in this OS comparing to another.

Choosing the best operating system

On Raspberry Pi 2, we have different operating systems :

Screenshot from http://www.raspberrypi.org/downloads/

• Raspbian is a valid candidate for our purpose, it's based on Debian, it has a GUI but can be launched without it (cool because we don't need it). Raspbian is the most used OS on Raspberry Pi so we can expect it to be the most stable.
• Snappy Ubuntu Core is in alpha version and we don't want an unstable computing farm so we won't keep this one.
• OpenELEC and Raspbmc are media centers so they don't fit in our project.
• Pidora, based on Fedora, could be valid but doesn't run on ARMV7 (Pidora is for ARMV6). A released version of Fedora seems to be the successor of Pidora because it's running on Raspberry Pi 2. For more informations, read this forum topic.
• Not in the list but still in competition, FreeBSD is a good candidate because it provides the minimum and it's preferred because we don't need much tools to make a computing farm. The only problem is that no version of FreeBSD has yet been released for Raspberry Pi 2, so we need to compile ourselves this version. Our project supervisor is actually working on that.

To conclude, for now we keep Raspbian, Fedora and FreeBSD as possible operating system for our computing farm, only the benchmarks will decide between these which one is the best operating system to achieve our objectives.

Introduction

We are two students in the Master 1 in Computer Science of the University of Nice-Sophia Antipolis (UNS).

Our second semester project is to create a Raspberry Pi 2 computing farm so we have to discover if it is worth the money. This computing farm will be used to make a resolution method that can be easily parallelised, meaning it will be integer-only computing, no matricial or linear computing.

What is Raspberry Pi 2?

Raspberry Pi is a series of credit card-sized single-board computers and the model 2 is the lastest released. For more informations and technical details, click here.

Picture of Raspberry Pi 2

The 2 different aspects of our work : software and hardware.

The software part consists in finding the best compiler and the best operating system regarding the final use.

The hardware part is about arrangement of space, temperature, energy consumption and money. We will think about how to put this computing farm in boxes (racks of 1U, 2U or 4U) to take the less space without burning them. Then we will look for alternative equipments (power supplies, network links, ...) that cost less or have less energy consumption to find the lower price for the best computing farm.

When all this work is done, we will compare the performance datas to the ones of a Intel I7 4970k processor to find out whether or not this farm costs less for the same (or better performance) than the I7.