[ExeterLUG] Raspberry Pi Cluster results...

[M Dinsmore]

I sent this email with some pictures (that Rick requested) on Monday but it seems have been over the size limit for the list and has gone to moderation!    Anyway, here is the text without the pictures... 

Hi All,


I've finally got some time to write up our results from our cluster experiments on Friday Night.  We managed to get 10 raspberry Pies in the cluster.


The target was to beat my laptop which ran the monte carlo pi calculation method in 4 minutes 50 Seconds.

Our results are as follows

No. of Pies Seconds 
 Minutes Seconds 
 Percentage Reduction in time taken Average Reduction 
1 1794.485 
 29 54 
 
 
 
2 1288.508 
 21 29 
 28.20% 28.20% 
3 859.134 
 14 19 
 33.32% 30.76% 
4 644.388 
 10 44 
 25.00% 28.84% 
5 515.717 
 8 36 
 19.97% 26.62% 
6 429.622 
 7 10 
 16.69% 24.64% 
7 368.231 
 6 8 
 14.29% 22.91% 
8 322.395 
 5 22 
 12.45% 21.42% 
9 286.442 
 4 46 
 11.15% 20.13% 
10 257.776 
 4 18 
 10.01% 19.01% 

As you can see we achieved our target of beating my laptop with 9 raspberry pies.  I guess had the program we ran on the laptop made use of both cores the time taken may have been considerably less.

/* I've also attached three screen shots which show the program running with 4, 9 and 10 pies in the cluster. */

In the discussions at the end we talked about how it would be possible to make the cluster easier to configure. Because the cluster relies on a fixed relationship between the IP Address/Hostname and the public keys to allow ssh to work seamlessly we needed to run with with static IP addresses.  This meant each node had to be manually configured with a unique hostname and IP address as it was added to the cluster, this hostname/IP address combination then needed to be added to the ssh known_hosts file.  It would be better if we could devise a more automated method of configuring new nodes - any suggestions are welcome.   

We also discussed other applications that we could use a raspberry pi cluster for - again suggestions are welcome.

Thanks again for your participation.

Malcolm
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