Add function for retrieving function rank count

Workload API now defines a function for retrieving the rank count
of a workload. Currently, only darshan workload implements this.
Will work on bgp workload and recorder later.

codes/codes-workload.h

@@ -136,6 +136,9 @@ void codes_workload_get_next(int wkld_id, int rank, struct codes_workload_op *op
 /* Reverse of the above function. */
 void codes_workload_get_next_rc(int wkld_id, int rank, const struct codes_workload_op *op);
 
+/* Retrieve the number of ranks contained in a workload */
+int codes_workload_get_rank_cnt(const char* type, const char* params);
+
 /* for debugging/logging: print an individual operation to the specified file */
 void codes_workload_print_op(FILE *f, struct codes_workload_op *op, int rank);
 

src/workload/codes-darshan-io-wrkld.c

@@ -43,6 +43,7 @@ struct rank_io_context
 /* Darshan workload generator's implementation of the CODES workload API */
 static int darshan_io_workload_load(const char *params, int rank);
 static void darshan_io_workload_get_next(int rank, struct codes_workload_op *op);
+static int darshan_io_workload_get_rank_cnt(const char *params);
 static int darshan_rank_hash_compare(void *key, struct qhash_head *link);
 
 /* Darshan I/O op data structure access (insert, remove) abstraction */
@@ -89,8 +90,11 @@ struct codes_workload_method darshan_io_workload_method =
     .method_name = "darshan_io_workload",
     .codes_workload_load = darshan_io_workload_load,
     .codes_workload_get_next = darshan_io_workload_get_next,
+    .codes_workload_get_rank_cnt = darshan_io_workload_get_rank_cnt,
 };
 
+static int total_rank_cnt = 0;
+
 /* hash table to store per-rank workload contexts */
 static struct qhash_table *rank_tbl = NULL;
 static int rank_tbl_pop = 0;
@@ -120,6 +124,11 @@ static int darshan_io_workload_load(const char *params, int rank)
         darshan_log_close(logfile_fd);
         return -1;
     }
+    if (!total_rank_cnt)
+    {
+        total_rank_cnt = job.nprocs;
+    }
+    assert(rank < total_rank_cnt);
 
     /* allocate the i/o context needed by this rank */
     my_ctx = malloc(sizeof(struct rank_io_context));
@@ -197,6 +206,8 @@ static void darshan_io_workload_get_next(int rank, struct codes_workload_op *op)
     struct rank_io_context *tmp = NULL;
     struct darshan_io_op next_io_op;
 
+    assert(rank < total_rank_cnt);
+
     /* find i/o context for this rank in the rank hash table */
     hash_link = qhash_search(rank_tbl, &my_rank);
 
@@ -238,6 +249,34 @@ static void darshan_io_workload_get_next(int rank, struct codes_workload_op *op)
     return;
 }
 
+static int darshan_io_workload_get_rank_cnt(const char *params)
+{
+    darshan_params *d_params = (darshan_params *)params;
+    darshan_fd logfile_fd;
+    struct darshan_job job;
+    int ret;
+
+    if (!d_params)
+        return -1;
+
+    /* open the darshan log to begin reading in file i/o info */
+    logfile_fd = darshan_log_open(d_params->log_file_path, "r");
+    if (logfile_fd < 0)
+        return -1;
+
+    /* get the per-job stats from the log */
+    ret = darshan_log_getjob(logfile_fd, &job);
+    if (ret < 0)
+    {
+        darshan_log_close(logfile_fd);
+        return -1;
+    }
+
+    darshan_log_close(logfile_fd);
+
+    return job.nprocs;
+}
+
 /* comparison function for comparing two hash keys (used for storing multiple io contexts) */
 static int darshan_rank_hash_compare(
     void *key, struct qhash_head *link)

src/workload/codes-workload-dump.c

@@ -32,7 +32,7 @@ void usage(){
             "Usage: codes-workload-dump --type TYPE --num-ranks N "
             "[--d-log LOG --d-aggregator-cnt CNT]\n"
             "--type: type of workload (\"darshan_io_workload\" or \"bgp_io_workload\")\n"
-            "--num-ranks: number of ranks to process\n"
+            "--num-ranks: number of ranks to process (if not set, it is set by the workload)\n"
             "--d-log: darshan log file\n"
             "--d-aggregator-cnt: number of aggregators for collective I/O in darshan\n"
             "--i-meta: i/o language kernel meta file path\n"
@@ -88,11 +88,6 @@ int main(int argc, char *argv[])
         usage();
         return 1;
     }
-    if (n == -1){
-        fprintf(stderr, "Expected \"--num-ranks\" argument\n");
-        usage();
-        return 1;
-    }
 
     int i;
     char *wparams;
@@ -136,6 +131,12 @@ int main(int argc, char *argv[])
         usage();
         return 1;
     }
+
+    /* if num_ranks not set, pull it from the workload */
+    if (n == -1){
+        n = codes_workload_get_rank_cnt(type, wparams);
+    }
+
     for (i = 0 ; i < n; i++){
         struct codes_workload_op op;
         printf("loading %s, %d\n", type, i);

src/workload/codes-workload-method.h

@@ -20,7 +20,7 @@ struct codes_workload_method
     char *method_name; /* name of the generator */
     int (*codes_workload_load)(const char* params, int rank);
     void (*codes_workload_get_next)(int rank, struct codes_workload_op *op);
-    void* (*codes_workload_get_info)(int rank);
+    int (*codes_workload_get_rank_cnt)(const char* params);
 };
 
 #endif /* CODES_WORKLOAD_METHOD_H */

src/workload/codes-workload.c

@@ -161,9 +161,23 @@ void codes_workload_get_next_rc(int wkld_id, int rank, const struct codes_worklo
     return;
 }
 
-void* codes_workload_get_info(int wkld_id, int rank)
+int codes_workload_get_rank_cnt(const char* type, const char* params)
 {
-    return method_array[wkld_id]->codes_workload_get_info(rank);
+    int i;
+    int rank_cnt;
+
+    for(i=0; method_array[i] != NULL; i++)
+    {
+        if(strcmp(method_array[i]->method_name, type) == 0)
+        {
+            rank_cnt = method_array[i]->codes_workload_get_rank_cnt(params);
+            assert(rank_cnt > 0);
+            return(rank_cnt);
+        }
+    }
+
+    fprintf(stderr, "Error: failed to find workload generator %s\n", type);
+    return(-1);
 }
 
 void codes_workload_print_op(FILE *f, struct codes_workload_op *op, int rank){