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Re: [GridSim-developers] [GridSim-users] simulation fails(OOME)with 1000 resources
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From: Shuo Y. <ya...@cs...> - 2008-09-05 14:57:24
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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 > |
