I am still struggling to follow the lecture material in Grid Computing, but none-the-less learning a lot and finding my feet in the more practical tutorials.
Week 7’s lecture discussed:
- Grid Resources
- Resource Specification
- Grid Processing
- Grid Application Hosting
In the tutorial we covered the MPI libraries for C and C++, this was followed up the next tutorial where we used WS_GRAM Job Management Client: globusrun-ws.
An example of a test script for MPI:
#include
#include
#include "mpi.h"
main(int argc, char* argv[])
{
int my_rank; /* rank of process */
int p; /* number of processes */
int source; /* rank of sender */
int dest; /* rank of receiver */
int tag = 0; /* tag for messages */
char message[100]; /* storage for message */
MPI_Status status; /* return status for */
/* receive */
char pname[100]; /* Processor name */
int plen; /* Processor name length */
/* Start up MPI */
MPI_Init(&argc, &argv);
/* Find out process rank */
MPI_Comm_rank(MPI_COMM_WORLD, &my_rank);
/* Find out number of processes */
MPI_Comm_size(MPI_COMM_WORLD, &p);
/* Find out my node name */
MPI_Get_processor_name(pname,&plen);
if (my_rank != 0)
{
/* Create message */
sprintf(message, "%s: Greetings from process %d!", pname, my_rank);
dest = 0;
/* Use strlen+1 so that '\0' gets transmitted */
MPI_Send(message, strlen(message)+1, MPI_CHAR, dest, tag, MPI_COMM_WORLD);
} else
{ /* my_rank == 0 */
printf("%s: Greetings from process %d!\n", pname, my_rank);
for (source = 1; source < p; source++)
{
MPI_Recv(message, 100, MPI_CHAR, source, tag, MPI_COMM_WORLD, &status);
printf("%s %s\n", pname, message);
}
}
We also explored distributed resource management systems (ie: Sun Grid Engine). I still however do not understand how RPC[Remote Procedure Call], MPI[Message Passing Interface] and DRM[Distributed Resource Management] interact.
Types of cluster applications:
- Sequential and totally uncoupled parallel applications
- Parallel applications (using message passing or shared memory)
- Distributed applications (ie: P2P)
I hope when we work more with some grid enabled applications, the grid resources management mechanisms become clearer to me, both as a user and implementer.