[SimGrid-user] simdag: platform design - cloud with a common storage center, routing problem

Aurélie Kong Win Chang aurelie.kong-win-chang at ens-lyon.fr
Mon Jun 26 10:32:54 CEST 2017


Hello,
Late answer (sorry), but thank you, everybody, I finally managed to have 
the platform I wanted.
It is based on the example Arnaud Legrand kindly sent me :

<platform version="4">
   <AS  id="AS0"  routing="Full">
      <AS id="Stockage" routing="Full">
         <host id="S" speed="100Mf"/>
         <link id="Whatever" bandwidth="41.279125MBps" latency="59.904us"/>
      </AS>
      <cluster id="C_A" prefix="A-" radical="0-99" suffix=".acme.org"
speed="1Gf" bw="125MBps" lat="50us"
            bb_bw="2.25GBps"  bb_lat="500us" router_id="router-A"/>
      <cluster id="C_B" prefix="B-" radical="0-99" suffix=".acme.org"
speed="1Gf" bw="125MBps" lat="50us"
            bb_bw="2.25GBps"  bb_lat="500us" router_id="router-B"/>
      <cluster id="C_C" prefix="C-" radical="0-99" suffix=".acme.org"
speed="1Gf" bw="125MBps" lat="50us"
            bb_bw="2.25GBps"  bb_lat="500us" router_id="router-C"/>
      <ASroute src="C_A" dst="C_B" gw_src="router-A" gw_dst="router-B">
         <link_ctn id="Whatever"/>
      </ASroute>
      <ASroute src="C_A" dst="C_C" gw_src="router-A" gw_dst="router-C">
         <link_ctn id="Whatever"/>
      </ASroute>
      <ASroute src="C_B" dst="C_C" gw_src="router-B" gw_dst="router-C">
         <link_ctn id="Whatever"/>
      </ASroute>
      <ASroute src="C_A" dst="Stockage" gw_src="router-A" gw_dst="S">
         <link_ctn id="Whatever"/>
      </ASroute>
      <ASroute src="C_B" dst="Stockage" gw_src="router-B" gw_dst="S">
         <link_ctn id="Whatever"/>
      </ASroute>
      <ASroute src="C_C" dst="Stockage" gw_src="router-C" gw_dst="S">
         <link_ctn id="Whatever"/>
      </ASroute>
   </AS>
</platform>


The xml with the model I was trying to describe is joined with the 
message (and it works! Yay!)
Thanks again,
Aurélie Kong Win Chang



Le 09/06/2017 à 19:25, Frédéric Suter a écrit :
> Hi Aurélie,
>
> You might be able to implement the setting you want by writing the 
> right platform file. In fact it really depends on whether your storage 
> center has "to do something" during the communications or not. If it 
> hasn't, you can write a platform such that the routes between every 
> pair of node (or cluster) goes through this central "node" (which can 
> be what we call a router).
>
> Another thing that has an impact on your platform file is whether 
> communications within a cluster also have to go through this storage 
> center or not. From what you asked, I understand that it is not the 
> case. Have a look at examples/platforms/dogbone.xml, it will give an 
> idea of what such a platform file could look like.
>
> hope it helps
>
> F.
>
>
> Le 07/06/2017 à 07:19, Aurélie Kong Win Chang a écrit :
>> Hello,
>>
>> I am implementing a simulator to do experiments on scheduling of 
>> scientific workflows on a cloud-typed platform. I use simDag to 
>> manage the dependencies between tasks.
>>
>> In my model, there is no peer-to-peer, all communications have to go 
>> through a storage center. But I don't know how to force the 
>> communications to do this. We found two solutions to handle this:
>>      - model the cloud as multiple clusters and manually apply a *2 
>> factor to all communications (which is what I am using for now) -- 
>> This supposes/models implicit distinct yet comparable up and down 
>> links between each cabinet and the host
>>      - model the cloud as multiple clusters and a separate host (the 
>> host will be the storage center, we don't take account of problem of 
>> accessibility or time to read/write, we are only interested in 
>> communication time). Then create in the workflow, between every pair 
>> of tasks with a link of dependence, a false task of amount of work of 
>> zero, which we would place on the "storage-center" host
>>
>> But to us, it's more workarounds there. Is there a better way to do 
>> this ?
>> Thanks by advance,
>>
>> Aurélie Kong Win Chang
>>
>> _______________________________________________
>> Simgrid-user mailing list
>> Simgrid-user at lists.gforge.inria.fr
>> https://lists.gforge.inria.fr/mailman/listinfo/simgrid-user
>

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