The connection on/off the iPad looks like an Ethernet port, I believe - but you should check that. Alternatively, you can send/recv across the wifi connection. No idea of the relative speeds, but you should be able to google that data.
On Nov 30, 2012, at 3:35 PM, shiny knight <theshinykni...@me.com> wrote: > I totally get your point Jeff, and thanks for pointing it out...this is an > aspect that I didn't consider yet. > > Power should not be an issue, since the devices are plugged in. Now I need to > evaluate exactly how much power I can pull while the device is connected to > the computer, compared to the power needed to run a process at 100% CPU load. > Running over batteries is absolutely out of question I guess; my calculations > should go on for at least a couple of hours, so I doubt that I can run a > small device with batteries and accomplish my objectives. > > Is there any info about how the I/O on the iPad and iPhone works? So I can > have an idea about what I can run on that cable and for how long. As you > pointed out, the main issue will be syncing processes...wifi may be feasible > but would be slower I guess (without specs is hard to even make assumptions). > > No worries, you are talking about things that has to be evaluated; I am just > exploring an alternate use of old hardware; which may result in not being > convenient at all in the end. So any comments helps :) > > I will focus on calculating what you suggested. Theoretically the dual core > Apple processors should be powerful enough to give some sort of performance > boost, but I am new to ARM so I don't really know too much about their > structure and pipeline, so I may be totally wrong. > > -lou > > > On Nov 30, 2012, at 7:35 AM, Jeff Squyres wrote: > >> Not to throw cold water on this, but I think the canonical problem cited >> with doing distributed computations on mobile devices is the power >> requirement. Meaning: if the devices are running on battery, you're really >> not going to get much computation out of them. >> >> And if you have them plugged in, you have a potential IO issue (i.e., how to >> get the input onto the device and the output out of the device). You >> probably only have 802.11g (maybe 802.11n?) wifi available, and you might >> have to deal with a LOT of I/O. Meaning: you might need to restrict this >> work to applications that are compute-heavy but IO-light. But then again, >> you're dealing with small, "slow" processors, so compute-heavy problems on >> such processors might not do so well. Or, more precisely, you might get >> much more compute efficiency with traditional "big" HPC servers. >> >> Don't get me wrong; I'm not trying to say this is a bad idea. I'm just >> saying that it's worth doing some back-of-the-envelope calculations before >> you spend a lot of effort on porting code to mobile platforms. >> >> For example, here's some interesting data points that would be good to >> calculate: >> >> 1. How many (pick your favorite mobile device; say -- iPhone 5) would it >> take to equal the power of one cheap Intel Sandy Bridge-based server with 16 >> cores? Compare things like max sustained FLOPS and IOPS (integer ops, not >> IO ops), RAM sizes, etc. >> >> 2. What's the procurement cost differential between 1 Intel Sandy >> Bridge-based server and N iPhone 5s? What's the operational cost >> differential? >> >> >> >> On Nov 30, 2012, at 10:25 AM, Ralph Castain wrote: >> >>> Just an FYI: xgrid is no longer being distributed or supported. >>> >>> I'd start by first building OMPI against the iOS simulator in Xcode. You >>> may run into some issues with the atomics that will need addressing, and >>> there may be other issues with syntax and header file locations. Best to >>> resolve those first. >>> >>> Once you get that to build, you can test running several procs on a single >>> iPad. If you have older iPads, I'm not sure that will work as they don't >>> multi-task. But might be worth a try. >>> >>> You'll then need to find a way to launch the processes across iPads. I >>> don't know if ssh will work, so you may have to devise a new plm module. I >>> can advise as you go. >>> >>> FWIW: I have an iPad 1 and iOS development kit, so I can potentially help >>> with problems. >>> >>> >>> On Nov 29, 2012, at 10:16 PM, shiny knight <theshinykni...@me.com> wrote: >>> >>>> Thanks for all your replies. >>>> >>>> As now I have access to 3 iOS devices and 1 Android, so if possible I >>>> would be oriented to pursue more the iOS route. >>>> >>>> So it seems that there is not yet a simple way to do so on these devices >>>> (Thanks for the paper posted Dominik); I will have to look deeper in that >>>> project that you mentioned and wait for some official release (at least >>>> for the Android side) >>>> >>>> I may install linux distro on a virtual machine; mostly I work on OSX so >>>> it should not be that bad (OSX allows me to work with both Android and iOS >>>> hassle free; that's why I had the thought to use my devices for MPI). >>>> >>>> Beatty: My idea is to use the devices only when plugged in; I was reading >>>> a paper about how to use MPI and dynamically change the number of nodes >>>> attached, while crunching data for a process. So it would be possible to >>>> add and remove nodes on the fly, and was trying to apply it to a portable >>>> device (http://www.cs.rpi.edu/~szymansk/papers/ppam05.pdf) before >>>> realizing that there is no MPI implementation for them. >>>> >>>> I would never envision a system where a user has a device in his pocket >>>> that is actually doing "something" behind is back...mine was a simple >>>> issue with having devices sitting on my desk, which I use to test my apps, >>>> and I could use these devices in a more productive way, while I have them >>>> tethered to my main machine (which is the main server where MPI >>>> development is done). >>>> >>>> Would you mind elaborate on the approach that you mentioned? I never used >>>> Xgrid, so I am not sure about how your solution would work. >>>> >>>> Thanks! >>>> >>>> Lou >>>> >>>> >>>> On Nov 29, 2012, at 4:14 PM, Beatty, Daniel D CIV NAVAIR, 474300D wrote: >>>> >>>>> Greetings Ladies and gentlemen, >>>>> There is one alternative approach and this a psuedo-cloud based MPI. The >>>>> idea is that MPI node list is adjusted via the cloud similar to the way >>>>> Xgrid's Bonjour used to do it for Xgrid. >>>>> >>>>> In this case, it is applying an MPI notion to the OpenCL codelets. There >>>>> are obvious issues with security, battery life, etc. There is >>>>> considerable >>>>> room for discussion as far expectations. Do jobs run free if the device >>>>> is >>>>> plugged in? If the device in the pocket, can the user switch to power >>>>> conservation/ cooler pockets? What constitutes fairness? Do owners have >>>>> a >>>>> right to be biased in judgement? These are tough questions that I think >>>>> I >>>>> will have to provide fair assurances for. After all, everyone likes to >>>>> think they are control of what they put in their pocket. >>>>> >>>>> V/R, >>>>> Dan >>>>> >>>>> >>>>> On 11/28/12 3:06 PM, "Dominik Goeddeke" >>>>> <dominik.goedd...@math.tu-dortmund.de> wrote: >>>>> >>>>>> shameless plug: >>>>>> http://www.mathematik.tu-dortmund.de/~goeddeke/pubs/pdf/Goeddeke_2012_EEV.pdf >>>>>> >>>>>> In the MontBlanc project (www.montblanc-project.eu), a lot of folks from >>>>>> all around Europe look into exactly this. Together with a few >>>>>> colleagues, we have been honoured to get access to an early prototype >>>>>> system. The runs for the paper above (accepted in JCP as of last week) >>>>>> have been carried out with MPICH2 back in June, but OpenMPI also worked >>>>>> flawlessly except for some issues with SLURM integration at the time we >>>>>> did those tests. >>>>>> >>>>>> The bottom line is: The prototype machine (128 Tegra2's) ran standard >>>>>> ubuntu, and since Android is essentially Linux, it should not be tooooo >>>>>> hard to get the system you envision up and running, Shiny Knight. >>>>>> >>>>>> Cheers, >>>>>> >>>>>> Dominik >>>>>> >>>>>> >>>>>> On 11/29/2012 12:00 AM, Vincent Diepeveen wrote: >>>>>>> You might want to post in beowulf mailing list see cc >>>>>>> and you want to install linux of course. >>>>>>> >>>>>>> OpenFabrics releases openmpi, yet it only works at a limited number of >>>>>>> distributions - most important is having >>>>>>> the correct kernel (usually old kernel). >>>>>>> >>>>>>> I'm gonna try get it to work at debian soon. >>>>>>> >>>>>>> >>>>>>> >>>>>>> On Nov 28, 2012, at 11:50 PM, shiny knight wrote: >>>>>>> >>>>>>>> I was looking for some info about MPI port on iOS or Android devices. >>>>>>>> >>>>>>>> I have some old devices that may result useful, if I could be able to >>>>>>>> include them in my computation scheme. >>>>>>>> >>>>>>>> OpenCL runs on iOS and Android, so I was wondering if there is any >>>>>>>> way to have an old iPhone/phone or iPad/tablet to run MPI. >>>>>>>> >>>>>>>> Tried to look everywhere, but I didn't find anything that says that >>>>>>>> it is possible, nor I've found any practical example. >>>>>>>> >>>>>>>> Thanks! >>>>>>>> _______________________________________________ >>>>>>>> users mailing list >>>>>>>> us...@open-mpi.org >>>>>>>> http://www.open-mpi.org/mailman/listinfo.cgi/users >>>>>>> >>>>>>> _______________________________________________ >>>>>>> users mailing list >>>>>>> us...@open-mpi.org >>>>>>> http://www.open-mpi.org/mailman/listinfo.cgi/users >>>>>> >>>>> _______________________________________________ >>>>> users mailing list >>>>> us...@open-mpi.org >>>>> http://www.open-mpi.org/mailman/listinfo.cgi/users >>>> >>>> _______________________________________________ >>>> users mailing list >>>> us...@open-mpi.org >>>> http://www.open-mpi.org/mailman/listinfo.cgi/users >>> >>> >>> _______________________________________________ >>> users mailing list >>> us...@open-mpi.org >>> http://www.open-mpi.org/mailman/listinfo.cgi/users >> >> >> -- >> Jeff Squyres >> jsquy...@cisco.com >> For corporate legal information go to: >> http://www.cisco.com/web/about/doing_business/legal/cri/ >> >> >> _______________________________________________ >> users mailing list >> us...@open-mpi.org >> http://www.open-mpi.org/mailman/listinfo.cgi/users > > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users
