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Re: [GridSim-developers] [GridSim-users] simulation fails(OOME)with 1000 resources
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From: ye <hua...@gm...> - 2008-09-05 15:55:04
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Hi, Dear all: to Shuo, Thanks for your advice and help! I have downloaded simjava1.2 from its original website. However, I am afraid it's not the same thing used within gridsim currently, at least partially. The source code included by GridSim concerns only the src package started from "gridsim.", such as gridsim.auction, gridsim.util. However, after I unfold the class package "gridsim.jar" (/gridsimtoolkit-4.1/jars/), I noticed it contains two aditional src package started as "eduni", e.g. eduni.simjava.distributions. These packages also appear in /gridsimtoolkit-4.1/jars/simjava2.jar. The trick is, original simjava1.2 doesn't have "eduni.simjava.distributions". Does that mean gridsim has modified some classes under package "eduni.simjava" (e.g. Evqueue) and "eduni.simjava.distributions", which is not from simjava itself. If the answer is true, then I am wondering about two questions: 1. Is there anyone have the source code of the modified simjava classes? I couldn't find it from gridsim source directory. 2. What's the reason of these modification? Did Dr. Buyya encounter the same problem what we have now? Then maybe people could contribute without tooooo much work. (what do you say, shuo? :-) Best Regards ye On Fri, Sep 5, 2008 at 4:55 PM, Shuo Yang <ya...@cs...> wrote: > All, > > I think the problem also lies in the scalability of the underlying simjava > package. Simjava uses an event queue to manage all internal events flying > between entities. The event queue is a Vector. If you refer to > eduni.simjava.Evqueue.java, you can see the doc: > > /** > * This class implements an event queue used internally by the Sim_system to > * manage > * the list of future and deferred Sim_events. It should not be needed in > * a user simulation. It works like a normal FIFO > * queue, but during insertion events are kept in order from the smallest > time > * stamp to the largest. This means the next event to occur will be at the > top > * of the queue. <P> > * The current implementation > * is uses a Vector to store the queue and is inefficient for popping > * and inserting elements because the rest of the array has to be > * moved down one space. A better method would be to use a circular array. > * @see eduni.simjava.Sim_system > * @version 0.1, 25 June 1995 > * @author Ross McNab > */ > > Also, the event queue in Sim_system is accessed using 'synchronized' to > ensure consistency and the simulation clock. Therefore when there are a huge > amount of entities/messages, the event queue becomes the system bottleneck - > only one entity/thread can write to event queue while the others will wait, > and wait, and wait, and wait... > > It may have problem with java's handling large memories. But a re-design > and re-implemenation of the underlying thread pool is ideal, which is > exactly what I'm doing now. > > Cheers, > > Shuo 'Alex' Yang > University of Manchester > > > ----- Original Message ----- From: "Agustín Caminero Herráez" < > ag...@ds...> > To: "ye" <hua...@gm...> > Cc: <gri...@li...>; < > gri...@li...> > Sent: Friday, September 05, 2008 3:35 PM > Subject: Re: [GridSim-developers] [GridSim-users] simulation > fails(OOME)with 1000 resources > > > > Hi Ye, > > I've also suffered the problems u describe, and I'm afraid there is no > solution for them. The only suggestion I can give to u is to scale down > your simulations. > > The problem comes from Java's inability to handle more than 1.5 GB of > memory, so there is nothing u can do. > > Just one thing, are u using Sun Java? Because using another different > java may cause problems... The java I us is Sun v1.4.2 > > Regards, > > Agustin > > ye escribió: > >> Hi, Dear all: >> Although I have asked a similar question in gridsim-user maillist, >> there seems no similar experience from other developers. Since it's an >> crucial problem for me, I'd to make the scenario much clear and beg >> for help. >> >> For brief, is there any scale limit for simulation created via GridSim? >> >> I was trying to set up a gridsim simulation with 1000 resource; each >> resource contains one machine, each machine has two PEs. Then, I wrote >> a user to retrieve resource list within its body(), and print the >> total size. However, the program halts with an OutOfMemoryError, every >> time before "Entities started" was printed. The user's body() was >> never visited. >> >> I am working on a mac 10.5, 2GB 667 Mhz memory, mac JVM 1.5; >> meanwhile, I already adjust the vm parameter into "-Xms512m -Xmx1024m". >> >> Later, I tried the same program on my server (ubuntu 8.04, 3.2GB). >> Fortunately, it works... but, it halts again with OOME while i decide >> create 1100 resources. >> >> I am not sure the problem is caused by lacking of memory? Is there any >> limit for gridsim simulation scale, or just for GridSim Resource? Or >> it's bug derived from simjava? >> >> Finally, is it possible to solve it? >> >> Thank you guys a lot!! >> >> regards >> ye >> >> -- >> Ye Huang, Department of Informatics >> University of Fribourg / Pérolles 2 - Bld de Pérolles 90 >> 1700 Fribourg, Switzerland >> >> e-mail: ye....@he..., ye....@un... >> http://diuf.unifr.ch/people/huangy/ >> Office: +41 26 429 65 95 >> ------------------------------------------------------------------------ >> >> ------------------------------------------------------------------------- >> This SF.Net email is sponsored by the Moblin Your Move Developer's >> challenge >> Build the coolest Linux based applications with Moblin SDK & win great >> prizes >> Grand prize is a trip for two to an Open Source event anywhere in the >> world >> http://moblin-contest.org/redirect.php?banner_id=100&url=/ >> ------------------------------------------------------------------------ >> >> _______________________________________________ >> Gridsim-users mailing list >> Gri...@li... >> https://lists.sourceforge.net/lists/listinfo/gridsim-users >> >> > -- > =============================================== > Agustin Caminero > Research Assistant. > Computing Systems Department. > Albacete Research Institute of Informatics (I3A). > The University of Castilla La Mancha. > Campus Universitario s/n, 02071, Albacete. Spain. > Phone: +34 967 599 200 Ext. 2693. Fax: +34 967 599 343 > http://www.i3a.uclm.es/ > =============================================== > > > > > > -------------------------------------------------------------------------------- > > > ------------------------------------------------------------------------- >> This SF.Net email is sponsored by the Moblin Your Move Developer's >> challenge >> Build the coolest Linux based applications with Moblin SDK & win great >> prizes >> Grand prize is a trip for two to an Open Source event anywhere in the >> world >> http://moblin-contest.org/redirect.php?banner_id=100&url=/ >> > > > > -------------------------------------------------------------------------------- > > > _______________________________________________ >> Gridsim-developers mailing list >> Gri...@li... >> https://lists.sourceforge.net/lists/listinfo/gridsim-developers >> >> > -- Ye Huang, Department of Informatics University of Fribourg / Pérolles 2 - Bld de Pérolles 90 1700 Fribourg, Switzerland e-mail: ye....@he..., ye....@un... http://diuf.unifr.ch/people/huangy/ Office: +41 26 429 65 95 |
