1. Grid Communication Simulator Boro Jakimovski Marjan Gusev Institute of Informatics Faculty of Natural Sciences and Mathematics University of Sts. Cyril and Metodius Skopje, Macedonia

2. Grid Programming Models There has been significant development of parallel programming models They cannot be applied directly to the Grid Infrastructure  MPI  Java RMI  Corba  …

3. MPI on the Grid MPI – Message Passing Interface MPICH – Well known MPI implementation MPICH-G2 – Globus device implemented

4. MPICH-G2

5. Performance Consideration Usage of TCP/IP as main transport protocol introduces lower performance Wide Area Network performance compared to specialized Cluster Network performance hence Trying to increase the overall performance

6. Performance Techniques MPICH-G2 over vendor MPI Better communication patterns  Topology aware collective communications Broadcast Gather/Scatter Barrier Reduce …

7. Example Binomial Tree  Optimal broadcast algorithm 0 910 11 56 7 3 8 4 1 2

8. Example Topology Unaware Solution 0 10 11 9 4 2 1 8 6 5 3 7

9. Example Topology Aware Solution 0 1 2 7 8 4 5 11 3 9 6 10

10. Grid Communication Simulator Implemented using Java 1.4 Purpose  Visual representation of communication patterns  Has implemented collective communications  In development

11. Grid Communication Simulator The programs executed on the virtual processors are Java programs  Example: import java.util.*; import edu.ii.grid.simulator.*; public class FlatTreeBroadcast extends edu.ii.grid.simulator.Program { public void run(){ if (processor.getID() == 0){ for (int i = 1; i < Processor.getCount(); i++){ Integer[] data = {new Integer(1)}; processor.send( new Packet( data, new GRIDAddress(i) ) ); } else { Packet p = null; p = processor.recieve(); }

12. Grid Communication Simulator Grid simulator main window

13. Grid Communication Simulator Grid simulator usage

14. Grid Communication Simulator

15. for (int i = 0; i < matriceA.length; i++) for (int j = 0; j < matriceA[i].length; j++) matriceA[i][j] = new Integer((int)(Math.random()*100)); row = CollectiveCommunication.flatTreeScatter(processor, matriceA);

16. Grid Communication Simulator