Add random selection option

Makefile

@@ -3,10 +3,10 @@ CFLAGS = -g -O0 -Wall
 all: swiftmpistepsim swiftmpifakestepsim
 
 swiftmpistepsim: swiftmpistepsim.c mpiuse.c mpiuse.h atomic.h cycle.h clocks.h clocks.c
-	mpicc $(CFLAGS) -o swiftmpistepsim swiftmpistepsim.c mpiuse.c clocks.c
+	mpicc $(CFLAGS) -o swiftmpistepsim swiftmpistepsim.c mpiuse.c clocks.c -lpthread
 
 swiftmpifakestepsim: swiftmpifakestepsim.c mpiuse.c mpiuse.h atomic.h cycle.h clocks.h clocks.c
-	mpicc $(CFLAGS) -o swiftmpifakestepsim swiftmpifakestepsim.c mpiuse.c clocks.c
+	mpicc $(CFLAGS) -o swiftmpifakestepsim swiftmpifakestepsim.c mpiuse.c clocks.c -lpthread
 
 clean:
 	rm -f swiftmpistepsim

mpiuse.c

@@ -263,18 +263,27 @@ struct mpiuse_log_entry *mpiuse_get_log(int ind) {
  *
  * @param nr_nodes the number of ranks that will be used.
  * @param nr_logs the number of logs to generate per rank.
- * @param size bytes per message
+ * @param size bytes per message, unless random when this is the maximum
+ *             and the minimum is 1.
+ * @param random whether to use random sizes.
+ * @param seed the random seed, use same for fixed sequences.
  */
-void mpiuse_log_generate(int nr_nodes, int nr_logs, int size) {
+void mpiuse_log_generate(int nr_nodes, int nr_logs, int size, int random,
+                         long int seed) {
+
+  /* Each rank exchanges messages with all the others and each "log" has the
+   * same size. */
+  if (random) srand48(seed);
 
-  /* Each rank exchange messages with all the others with a fixed size. */
   int tag = 1;
   for (int k = 0; k < nr_logs; k++) {
+    int logsize = size;
+    if (random) logsize = (drand48() * (double)size) + 1;
     for (int i = 0; i < nr_nodes; i++) {
       for (int j = 0; j < nr_nodes; j++) {
         if (i != j) {
-          mpiuse_log_allocation(i, 1, k, SEND_TYPE, NO_SUBTYPE, 1, size, j, tag);
-          mpiuse_log_allocation(j, 1, k, RECV_TYPE, NO_SUBTYPE, 1, size, i, tag);
+          mpiuse_log_allocation(i, 1, k, SEND_TYPE, NO_SUBTYPE, 1, logsize, j, tag);
+          mpiuse_log_allocation(j, 1, k, RECV_TYPE, NO_SUBTYPE, 1, logsize, i, tag);
         }
       }
     }

mpiuse.h

@@ -101,6 +101,7 @@ int mpiuse_nr_logs(void);
 int mpiuse_nr_ranks(void);
 void mpiuse_dump_logs(int nranks, const char *logfile);
 
-void mpiuse_log_generate(int nr_nodes, int nr_logs, int size);
+void mpiuse_log_generate(int nr_nodes, int nr_logs, int size, int random,
+                         long int seed);
 
 #endif /* SWIFT_MPIUSE_H */

swiftmpifakestepsim.c

@@ -38,6 +38,9 @@ static int verbose = 0;
 /* Set a data pattern and check we get this back, slow... */
 static int datacheck = 0;
 
+/* Fixed seed for pseudorandoms. */
+static long int seed = 1987654321;
+
 /* The local queues. */
 static struct mpiuse_log_entry **volatile reqs_queue;
 static int volatile ind_req = 0;
@@ -338,7 +341,8 @@ static void pick_logs(void) {
 static void usage(char *argv[]) {
   fprintf(stderr, "Usage: %s [-vf] nr_messages logfile.dat\n",
           argv[0]);
-  fprintf(stderr, " options: -v verbose, -d data check, -s size (bytes)\n");
+  fprintf(stderr, " options: -v verbose, -d data check, -s size (bytes), -r"
+          " random from 0 to size\n");
   fflush(stderr);
 }
 
@@ -362,10 +366,12 @@ int main(int argc, char *argv[]) {
     error("Call to MPI_Comm_rank failed with error %i.", res);
 
   /* Handle the command-line, we expect the number of messages to exchange per
-   * rank an output log and some options. */
+   * rank an output log and some options, the interesting ones are a size and
+   * whether to use a random selection (with a fixed seed). */
   int size = 1024;
+  int random = 0;
   int opt;
-  while ((opt = getopt(argc, argv, "vds:")) != -1) {
+  while ((opt = getopt(argc, argv, "vds:r")) != -1) {
     switch (opt) {
       case 'd':
         datacheck = 1;
@@ -373,6 +379,9 @@ int main(int argc, char *argv[]) {
       case 's':
         size = atoi(optarg);
         break;
+      case 'r':
+        random = 1;
+        break;
       case 'v':
         verbose = 1;
         break;
@@ -392,9 +401,16 @@ int main(int argc, char *argv[]) {
   char *logfile = argv[optind + 1];
 
   /* Generate the fake logs for the exchanges. */
-  if (myrank == 0) message("Generating %d fake logs for %d ranks of size %d",
-                           nr_logs, nr_nodes, size);
-  mpiuse_log_generate(nr_nodes, nr_logs, size);
+  if (myrank == 0) {
+    if (random) {
+      message("Generating %d fake logs for %d ranks with random distribution"
+              " up to size %d", nr_logs, nr_nodes, size);
+    } else {
+      message("Generating %d fake logs for %d ranks of size %d",
+              nr_logs, nr_nodes, size);
+    }
+  }
+  mpiuse_log_generate(nr_nodes, nr_logs, size, random, seed);
   int nranks = mpiuse_nr_ranks();
 
   /* Each rank requires its own queue, so extract them. */