check in a ping-pong test benchmark

This commit was SVN r2029.

src/mca/ptl/elan/tests/lat.c

@@ -0,0 +1,80 @@
+
+#include <stdio.h>
+#include <math.h>
+#include "mpi.h"
+#include "test_util.h"
+
+#define MYBUFSIZE (4*1024*16)
+char        s_buf[MYBUFSIZE];
+char        r_buf[MYBUFSIZE];
+int         skip = 0;
+
+int
+main (int argc, char *argv[])
+{
+    char hostname[32];
+
+    int         myid, numprocs, i;
+    double      startwtime = 0.0, endwtime;
+    int         namelen;
+    int         size;
+    int         loop;
+    MPI_Status  stat;
+    int         sleep = 1;
+
+    double      t_start, t_end;
+
+    if (argc < 2) {
+        fprintf (stderr, "Usage: %s msg_size\n", argv[0]);
+        MPI_Finalize ();
+        return 0;
+    }
+    size = atoi (argv[1]);
+
+    /* Get some environmental variables set for Open MPI, OOB */
+    env_init_for_elan();
+
+    MPI_Init (&argc, &argv);
+    MPI_Comm_size (MPI_COMM_WORLD, &numprocs);
+    MPI_Comm_rank (MPI_COMM_WORLD, &myid);
+
+    /* touch the data */
+    for (i = 0; i < size; i++) {
+        s_buf[i] = 'a' + i;
+    }
+
+    /*MPI_Barrier (MPI_COMM_WORLD);*/
+
+    loop = 1;
+    gethostname(hostname, 32);
+    fprintf(stdout, "[%s:%s:%d] done with init and barrier\n",
+	    hostname, __FUNCTION__, __LINE__);
+    fflush(stdout);
+
+    for (i = 0; i < loop + skip; i++) {
+	if (i == skip)
+	    t_start = MPI_Wtime ();
+	if (myid == 0) {
+            MPI_Send (s_buf, size, MPI_CHAR, 1, i, MPI_COMM_WORLD);
+	} else {
+            MPI_Recv (r_buf, size, MPI_CHAR, 0, i, MPI_COMM_WORLD,
+                      &stat);
+        }
+    }
+
+    fprintf(stdout, "[%s:%s:%d] done with pingpong\n",
+	    hostname, __FUNCTION__, __LINE__);
+    fflush(stdout);
+ 
+    t_end = MPI_Wtime ();
+
+    if (myid == 0) {
+        double      latency;
+        latency = (t_end - t_start) * 1.0e6 / (2.0 * loop);
+	fprintf(stdout, "length %d latency %8f\n", 
+		size, latency);
+	fflush(stdout);
+    }
+    MPI_Finalize ();
+    return 0;
+}