Re: [GridSim-users] how create machines during the simulation

[Marcos D. de A. <ma...@cs...>]

Dear Gilberto,

In theory you could create a GridResource dynamically during the  
simulation in the same way that you create GridResources before the  
simulation starts. One entity could, for example, create a resource  
with the required characteristics. The constructors of the Sim_entity  
class call Sim_system.add(this) to include the just created entity to  
the list of entities created. The method  add of sim_system is as  
follows:

   /**
    * Add a new entity to the simulation. This is present for  
compatibility with existing
    * simulations since entities are automatically added to the  
simulation upon instantiation.
    * @param e The new entity
    */
   public static void add(Sim_entity e) {
     Sim_event evt;
     if (running) {
       // Post an event to make this entity
       evt = new Sim_event(Sim_event.CREATE,clock,current_ent().get_id 
(),0,0, e);
       future.add_event(evt);
     } else {
       if (e.get_id()==-1) { // Only add once!
	e.set_id(entities.size());
	entities.add(e);
       }
     }
   }

Basically, if the simulation is running, it will schedule one event,  
which is handled by Sim_system itself in a private method.

Everything looks fine. However, in practice SimJava has a bug because  
future.add_event(evt); may raise an exception as it is not  
synchronised and the list called future (containing the future  
simulation events) may be changed simultaneously by two entities. I  
had concurrent modification problems with the auction framework when  
adding entities at runtime. It is actually simple to solve it, but it  
requires one to change SimJava.

Regards,

Marcos


On 11/06/2008, at 5:28 PM, Agustín Caminero Herráez wrote:

> Hello,
>
> I don't think u can create gridResources dynamically during  
> simulations.
>
> What u can do instead is use the resource failure functionality and  
> set resources initially as failed, then make them available as sim  
> progresses.
>
> This way u would simulate the dynamic creation of GridResources.
>
> Regards,
>
> Agustin
>
>
> Gilberto Cunha escribió:
>>
>> Hello,
>>
>> I have a question regarding GridResource.
>> My doubt is as follows:
>>
>> How can i create GridResources during the simulation, in a dynamic  
>> way?
>>
>> Regards,
>> -- 
>> Gilberto Cunha Filho
>> gil...@gm... <mailto:gil...@gm...>
>> SISMO - Laboratório de Sistemas e Mobilidade
>> UFMA
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>
> -- 
> ===============================================
> Agustin Caminero
> PhD Student
> Computing Systems Department
> The University of Castilla La Mancha, Albacete. Spain.
> Phone: +34 967 599 200 Ext. 2693. Fax: +34 967 599 343
> http://www.i3a.uclm.es/
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