RollyLollyPolly
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Re: Super computer rack?

Tue Apr 03, 2012 4:09 am

A far fetched thought.

If we got 64 raspberry pi's to work together, would we be able to make a mini-supercomputer.

Just wondering.

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Vindicator
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Re: Super computer rack?

Tue Apr 03, 2012 4:34 am

Look for threads on brambles and you may find your answer (raspberrypi clusters are being called brambles LOL)
If you are more worried about ,spelling, punctuation or grammar you have probably already missed the point so please just move on.

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RaTTuS
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Re: Super computer rack?

Tue Apr 03, 2012 7:14 am

yes YMMV

see above post for brambles - and it all depends on what you want to do
How To ask Questions :- http://www.catb.org/esr/faqs/smart-questions.html
WARNING - some parts of this post may be erroneous YMMV

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skeptik
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Re: Super computer rack?

Thu Apr 05, 2012 11:24 am

I've been searching for posts on brambles, and haven't seen a lot; i'm not  clear on whether it's even possible for an ordinary user to setup a bramble assuming these become purchaseable in quantity at some point. I had a look but the wiki gave no result.

I was just wondering if it was possible to do something like rendering work using these devices, or would it be more trouble trying to set them up to work together properly in this fashion than it's worth?

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RaTTuS
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Re: Super computer rack?

Thu Apr 05, 2012 11:32 am

http://www.raspberrypi.org/for.....8;search=1

skeptik said:


I was just wondering if it was possible to do something like rendering work using these devices, or would it be more trouble trying to set them up to work together properly in this fashion than it's worth?


yes - depending on how or what it is your doing .

if the task can be parallelised easily then yes [you could pull all useful info from a common network source and perform the calulations on the CPU / GPU and send them back to a network location.

if they need lots of communication between the nodes then it is going to be less useful
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nick.mccloud
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Re: Super computer rack?

Thu Apr 05, 2012 11:40 am

skeptik said:


I've been searching for posts on brambles, and haven't seen a lot;


Using the search on the home page for bramble brings up 118 results!


i'm not  clear on whether it's even possible for an ordinary user to setup a bramble assuming these become purchaseable in quantity at some point. I had a look but the wiki gave no result.

I was just wondering if it was possible to do something like rendering work using these devices, or would it be more trouble trying to set them up to work together properly in this fashion than it's worth?


Depends on how you define 'ordinary user' - setting up a cluster takes some serious hacking.

mole125
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Re: Super computer rack?

Thu Apr 05, 2012 11:44 am

skeptik said:


I've been searching for posts on brambles, and haven't seen a lot; i'm not  clear on whether it's even possible for an ordinary user to setup a bramble assuming these become purchaseable in quantity at some point. I had a look but the wiki gave no result.

I was just wondering if it was possible to do something like rendering work using these devices, or would it be more trouble trying to set them up to work together properly in this fashion than it's worth?


The problem is this is a really vague question - all a bramble really means at this stage is having multiple computers working together to achieve a single aim. The simple answer is of course.

The hard part is working out how to do this efficiently and effectively and so whether it is worth the effort. The RPi has excellent GPU capabilities, mediocre CPU capabilities and limited IO capabilities (ethernet and USB share same badwidth and so sustaining high bitrate transfers between pis is likely to be very difficult.

This means that a truly clustered operating system running across the multiple cores is likely to be only of interest for academic purposes (you'll get more for your bucks with a normal desktop PC). Similarly a multinode modelling problem where neighbouring nodes need to share lots of data is also be limited.

The scenario that you mention - a render farm - is probably one of the most practical real life scenarios where the RPi may be suited depending on what sort of rendering problem you are doing. Most decent rendering software is already designed to allow multiple agents to be distributed on the network with a master agent controlling them.

You submit the job to the master node, this dishes out each frame to each node and then the nodes effectively work independently before returning the results to the master/output network drive). Each node can operate independently from it's neighbours and the input 3d model size and output bitmap is relatively tiny compared to the processing time.

Of course to be sensible you would need to find a rendering package that could actually make full use of the GPU rather than just doing it on the processor.

If you can find the right software this should be a case of deploy it on each RPi and run the job.

lb
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Re: Super computer rack?

Thu Apr 05, 2012 4:07 pm

A Raspberry Pi cluster isn't worth the effort. Both CPU and GPU are more than an order of magnitude slower than cheap and common PC hardware, and communication between the Pis would be heavily bottlenecked.

Now if you want to experiment with clustering, you can do that of course, but don't expect to outrun your desktop PC.

skeptik
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Re: Super computer rack?

Fri Apr 06, 2012 5:34 am

nmcc said:

skeptik said:

I"ve been searching for posts on brambles, and haven"t seen a lot;

Using the search on the home page for bramble brings up 118 results!

http://www.raspberrypi.org/faqs says to "Search the forums for Bramble – lots of discussion on this subject."

And it"s true that there are a lot of results, but most of them are irrelevant.

Introduce yourself!
News articles and blog posts about Raspberry Pi
R-Pi Massively Multiplayer Online Role-Playing Games (MMORPG)
Cases for the Raspberry Pi

and so on.
On of the forum posts says the answer is in the wiki.
http://elinux.org/index.php?ti.....#038;go=Go

gives
"There were no results matching the query. "

So the info might well be in there, somewhere, but a FAQ or even a wiki entry about the Bramble saying "it"s not useful except as an academic exercise" would be very handy, and save having to answer the question again. Not to mention I"ve seen the cluster named as a "Bramble" and as "Brambles", which just screws up search results. Even a url in the FAQs to a the relevant forum postings would save time.

One of the first things i saw in assorted blogs about the R. Pi was speculation about it"s usefulness as a device in a cluster, but since it's design wasn't finalised, everyone just said wait and see and there was no followup.

Thanks for the answer. If anyone has the rights to edit the faqs or the wiki, can i suggest making that sort of change to help out the next newbie?

Sorry about the messy formatting, i really don't understand this editor, I wish it would expose the tagging but it looks like you have to install a plug in to have more control over the editting; and i'm unlikely to post again.

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Jessie
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Re: Super computer rack?

Sat Apr 07, 2012 7:22 am

skeptik said:


Thanks for the answer. If anyone has the rights to edit the faqs or the wiki, can i suggest making that sort of change to help out the next newbie?


Anyone can edit a Wiki, yourself included.  That is how they work.

bobc
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Re: Super computer rack?

Sat Apr 07, 2012 11:42 am

RollyLollyPolly said:


A far fetched thought.

If we got 64 raspberry pi's to work together, would we be able to make a mini-supercomputer.

Just wondering.



The short answer is "not really practical" since there is a lot more to a supercomputer than just a bunch of cheap CPUs. But you can make a processing cluster with anything that has a CPU and a network interface, and it will be effective for a range of applications that lend easily to loosely-coupled parallel tasks.

For that, the R-pi is a cheap enough, but is probably not the best MIPS/$. Putting together 64 R-Pis might cost around £2,500, so you might think twice about spending that much.

For learning about parallel computing and the problems involved, R-Pi could be suitable, and you have always got 64 R-Pis which can be re-used afterwards.

I got to thinking though, what would make a good DIY cluster node? I didn't find anything obvious on google, so maybe no-one has done it. You can get a 1GHz Cortex A8 for < £10, with some RAM, ethernet for comms interface you have the guts of a relatively low cost node. For £4 you can get a 450MHz ARM9, would be a cheaper entry point, although the A8 still has better MIPS/$.

I am currently designing some bare-bone modules based on smaller Cortex M3 parts, I think I will look into doing an ARM9 module based on something like the Freescale iMX233, which is a nice package but doesn't have an ethernet interface.

gunghoguy
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Re: Super computer rack?

Thu Oct 22, 2015 7:40 am

Yesterday I went to the Electronics Design Show in Coventry. Lots of firms are making Systems On Modules (SOMs) of this sort but they all seem to be too complicated and expensive -- too like the original Pi than the Compute Module. A compute module with just the Broadcom package and memory of the RasPi B2, and a faster interface than the original compute module, would be welcome.

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