Assignment 3 - MPI

 * ping-pong for latency code done by Umbreen - buggy
 * reduction done by Viktor
 * result.c done by Gaurav
Signed-off-by: Gaurav Kukreja <mailme.gaurav@gmail.com>

mpi-assign3/Makefile

+CC = mpicc
+CFLAGS = -O3 
+
+all: ping-pong reduction
+
+ping-pong: ping-pong.o result.o
+	$(CC) $(CFLAGS) -o $@ $+
+
+reduction: reduction.o
+	$(CC) $(CFLAGS) -o $@ $+
+
+clean: 
+	rm -rf *.o reduction ping-pong

mpi-assign3/ping-pong.c

+#include "mpi.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include "result.h"
+
+#define FNAME_CMDARG 1
+extern char *filename;
+
+struct data_latency data_l;
+
+int main (int argc, char **argv)
+{
+
+	int my_proc,other_proc,i,j, nprocs;
+	int tag=10;
+	char a, b;
+	double tstart, tend;
+	MPI_Status status;
+
+	filename = argv[FNAME_CMDARG];
+
+	MPI_Init(&argc, &argv);
+	MPI_Comm_size(MPI_COMM_WORLD, &nprocs);
+	MPI_Comm_rank(MPI_COMM_WORLD, &my_proc);
+
+	for(i=1; i<nprocs; i++)
+	{
+		other_proc=i;
+		MPI_Barrier(MPI_COMM_WORLD);
+
+
+		if (my_proc == 0) {
+
+			tstart = MPI_Wtime();
+			for(j=0; j<5; j++)
+			{
+				MPI_Send(&a, 0, MPI_DOUBLE, other_proc, 10, MPI_COMM_WORLD);
+				MPI_Recv(&b, 0, MPI_DOUBLE, other_proc, 10, MPI_COMM_WORLD, &status);
+			}
+			tend = MPI_Wtime();
+
+		} else {
+			for(j=0; j<5; j++)
+			{
+				MPI_Recv(&b, 0, MPI_DOUBLE, 0, 10, MPI_COMM_WORLD, &status);
+
+				MPI_Send(&b, 0, MPI_DOUBLE, 0, 10, MPI_COMM_WORLD);
+			}
+
+		}
+
+		MPI_Barrier(MPI_COMM_WORLD);
+		data_l.source_thread = 0;
+		data_l.dest_thread = other_proc;
+		data_l.latency = (tend - tstart)/10;
+		submit_latency_data(data_l);
+		printf("Latency for process %d = %lf\n",other_proc, tend-tstart);
+	}
+	MPI_Finalize();
+}

mpi-assign3/reduction.c

+#include "mpi.h"
+#include <stdio.h>
+#include <stdlib.h>
+
+main (int argc,char *argv[])
+{
+	int myid, np, ierr;
+	int a, tmp, i,tag;
+	MPI_Status status;
+
+	ierr = MPI_Init (&argc, &argv);
+	if (ierr != MPI_SUCCESS)
+	{
+		printf("Cannot initialize MPI!\n");
+		MPI_Finalize();
+		exit(0);
+	}
+
+	MPI_Comm_size(MPI_COMM_WORLD, &np);
+	MPI_Comm_rank(MPI_COMM_WORLD, &myid);
+
+	// ToDo: Check if np is a power of 2
+
+	a = myid;
+	i = 1;
+	tag = 1; // tag can be an arbitrary value
+
+	while (i < np)
+	{
+		if (myid%(2*i) == 0)
+		{
+		    MPI_Recv(&tmp, 1, MPI_INT, myid+i, tag, MPI_COMM_WORLD, &status);
+		    a = a + tmp;
+		}
+		if (myid%(2*i) == i)
+		{
+		    MPI_Send(&a, 1, MPI_INT, myid-i, tag, MPI_COMM_WORLD);
+		}
+		i = i*2;
+		MPI_Barrier( MPI_COMM_WORLD); // may not be required
+	}
+
+	if (myid == 0)
+	{
+		printf("Number of Threads = %d\n", np);
+		printf("Result = %d\n", a);	
+	}
+
+	MPI_Finalize();
+}

mpi-assign3/result.c

+#include <stdio.h>
+#include "result.h"
+
+char *filename;
+
+int submit_bandwidth_data(struct data_bandwidth data_b)
+{
+	FILE* fp;
+	fp = fopen(filename, "a");
+
+	fprintf(fp, "%d/t%d/t%d/t%lf/t%lf/n", data_b.source_thread,
+			data_b.dest_thread, data_b.log_size, 
+			data_b.time, data_b.bandwidth);
+
+	fclose(fp);
+	return 1;
+}
+
+int submit_latency_data(struct data_latency data_l)
+{
+	FILE* fp;
+	fp=fopen(filename, "a");
+	
+	fprintf(fp, "%d/t%d/t%lf/n", data_l.source_thread,
+			data_l.dest_thread, data_l.latency);
+
+	fclose(fp);
+	return 1;
+}
+

mpi-assign3/result.h

+#ifndef RESULT_H
+#define RESULT_H
+
+struct data_latency {
+	int source_thread;
+	int dest_thread;
+	double latency;
+};
+
+struct data_bandwidth {
+	int source_thread;
+	int dest_thread;
+        int log_size;
+	double time;
+	double bandwidth;
+};
+
+int submit_latency_data(struct data_latency);
+
+int submit_bandwidth_data(struct data_bandwidth);
+
+#endif