1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
|
/****************************************************************************
* FILE: mpi_bandwidth.c
* DESCRIPTION:
* Provides point-to-point communications timings for any even
* number of MPI tasks.
* AUTHOR: Blaise Barney
* LAST REVISED: 04/13/05
****************************************************************************/
#include "mpi.h"
#include <stdio.h>
#include <stdlib.h>
#include <sys/time.h>
#include <time.h>
#define MAXTASKS 8192
/* Change the next four parameters to suit your case */
#define STARTSIZE 100000
#define ENDSIZE 1000000
#define INCREMENT 100000
#define ROUNDTRIPS 100
int main (int argc, char *argv[])
{
int numtasks, rank, n, i, j, rndtrps, nbytes, start, end, incr,
src, dest, tag=1, taskpairs[MAXTASKS], namelength;
double thistime, bw, bestbw, worstbw, totalbw, avgbw,
bestall, avgall, worstall,
timings[MAXTASKS/2][3], tmptimes[3],
resolution, t1, t2;
char msgbuf[ENDSIZE], host[MPI_MAX_PROCESSOR_NAME],
hostmap[MAXTASKS][MPI_MAX_PROCESSOR_NAME];
MPI_Status status;
/* Some initializations and error checking */
MPI_Init(&argc,&argv);
MPI_Comm_size(MPI_COMM_WORLD, &numtasks);
if (numtasks % 2 != 0) {
printf("ERROR: Must be an even number of tasks! Quitting...\n");
MPI_Abort(MPI_COMM_WORLD, 1);
exit(0);
}
MPI_Comm_rank(MPI_COMM_WORLD, &rank);
start = STARTSIZE;
end = ENDSIZE;
incr = INCREMENT;
rndtrps = ROUNDTRIPS;
for (i=0; i<end; i++)
msgbuf[i] = 'x';
/* All tasks send their host name to task 0 */
MPI_Get_processor_name(host, &namelength);
MPI_Gather((void*)&host, MPI_MAX_PROCESSOR_NAME, MPI_CHAR, (void*)&hostmap,
MPI_MAX_PROCESSOR_NAME, MPI_CHAR, 0, MPI_COMM_WORLD);
/* Determine who my send/receive partner is and tell task 0 */
if (rank < numtasks/2)
dest = src = numtasks/2 + rank;
if (rank >= numtasks/2)
dest = src = rank - numtasks/2;
MPI_Gather(&dest, 1, MPI_INT, (void*)&taskpairs, 1, MPI_INT, 0, MPI_COMM_WORLD);
if (rank == 0) {
resolution = MPI_Wtick();
printf("\n******************** MPI Bandwidth Test ********************\n");
printf("Message start size= %d bytes\n",start);
printf("Message finish size= %d bytes\n",end);
printf("Incremented by %d bytes per iteration\n",incr);
printf("Roundtrips per iteration= %d\n",rndtrps);
printf("MPI_Wtick resolution = %e\n",resolution);
printf("************************************************************\n");
for (i=0; i<numtasks; i++)
printf("task %4d is on %s partner=%4d\n",i,hostmap[i],taskpairs[i]);
printf("************************************************************\n");
}
/*************************** first half of tasks *****************************/
/* These tasks send/receive messages with their partner task, and then do a */
/* few bandwidth calculations based upon message size and timings. */
if (rank < numtasks/2) {
for (n=start; n<=end; n=n+incr) {
bestbw = 0.0;
worstbw = .99E+99;
totalbw = 0.0;
nbytes = sizeof(char) * n;
for (i=1; i<=rndtrps; i++){
t1 = MPI_Wtime();
MPI_Send((void*)&msgbuf, n, MPI_CHAR, dest, tag, MPI_COMM_WORLD);
MPI_Recv((void*)&msgbuf, n, MPI_CHAR, src, tag, MPI_COMM_WORLD, &status);
t2 = MPI_Wtime();
thistime = t2 - t1;
bw = ((double)nbytes * 2) / thistime;
totalbw = totalbw + bw;
if (bw > bestbw ) bestbw = bw;
if (bw < worstbw ) worstbw = bw;
}
/* Convert to megabytes per second */
bestbw = bestbw/1000000.0;
avgbw = (totalbw/1000000.0)/(double)rndtrps;
worstbw = worstbw/1000000.0;
/* Task 0 collects timings from all relevant tasks */
if (rank == 0) {
/* Keep track of my own timings first */
timings[0][0] = bestbw;
timings[0][1] = avgbw;
timings[0][2] = worstbw;
/* Initialize overall averages */
bestall = 0.0;
avgall = 0.0;
worstall = 0.0;
/* Now receive timings from other tasks and print results. Note */
/* that this loop will be appropriately skipped if there are */
/* only two tasks. */
for (j=1; j<numtasks/2; j++)
MPI_Recv((void*)&timings[j], 3, MPI_DOUBLE, j, tag, MPI_COMM_WORLD, &status);
printf("***Message size: %8d *** best / avg / worst (MB/sec)\n",n);
for (j=0; j<numtasks/2; j++) {
printf(" task pair: %4d - %4d: %4.2f / %4.2f / %4.2f \n",
j, taskpairs[j], timings[j][0], timings[j][1], timings[j][2]);
bestall += timings[j][0];
avgall += timings[j][1];
worstall += timings[j][2];
}
printf(" OVERALL AVERAGES: %4.2f / %4.2f / %4.2f \n\n",
bestall/(numtasks/2), avgall/(numtasks/2), worstall/(numtasks/2));
}
else {
/* Other tasks send their timings to task 0 */
tmptimes[0] = bestbw;
tmptimes[1] = avgbw;
tmptimes[2] = worstbw;
MPI_Send(tmptimes, 3, MPI_DOUBLE, 0, tag, MPI_COMM_WORLD);
}
}
}
/**************************** second half of tasks ***************************/
/* These tasks do nothing more than send and receive with their partner task */
if (rank >= numtasks/2) {
for (n=start; n<=end; n=n+incr) {
for (i=1; i<=rndtrps; i++){
MPI_Recv((void*)&msgbuf, n, MPI_CHAR, src, tag, MPI_COMM_WORLD, &status);
MPI_Send((void*)&msgbuf, n, MPI_CHAR, dest, tag, MPI_COMM_WORLD);
}
}
}
MPI_Finalize();
} /* end of main */
|
