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
