very early skeleton of workload component

still need:
- test program
- shim layer logic (for reverse computation)
- example method

codes/codes-workload.h

+/*
+ * Copyright (C) 2013 University of Chicago.
+ * See COPYRIGHT notice in top-level directory.
+ *
+ */
+
+/* I/O workload generator API to be used by storage simulations */
+
+#ifndef CODES_WORKLOAD_H
+#define CODES_WORKLOAD_H
+
+#include "ross.h"
+
+/* supported I/O operations */
+enum codes_workload_op_type
+{
+    /* terminator; there are no more operations for this rank */
+    CODES_WK_END = 1, 
+    /* sleep/delay to simulate computation or other activity */
+    CODES_WK_DELAY,
+    /* block until specified ranks have reached the same point */
+    CODES_WK_BARRIER,
+    /* open */
+    CODES_WK_OPEN,
+    /* close */ 
+    CODES_WK_CLOSE,
+    /* write */
+    CODES_WK_WRITE,
+    /* read */
+    CODES_WK_READ
+};
+
+/* I/O operation paramaters */
+struct codes_workload_op
+{
+    /* TODO: do we need different "classes" of operations to differentiate
+     * between different APIs?
+     */
+
+    enum codes_workload_op_type op_type;
+
+    union
+    {
+        struct {
+            double seconds;
+        } delay;
+        struct {
+            int count;  /* num ranks in barrier */
+            int root;   /* root rank */
+        } barrier;
+        struct {
+            int file_id;      /* integer identifier for the file */
+            int create_flag;  /* file must be created, not just opened */
+        } open;
+        struct {
+            int file_id;  /* file to operate on */
+            off_t offset; /* offset and size */
+            size_t size;
+        } write;
+        struct {
+            int file_id;  /* file to operate on */
+            off_t offset; /* offset and size */
+            size_t size;
+        } read;
+        struct {
+            int file_id;  /* file to operate on */
+        } close;
+    };
+};
+
+/* load and initialize workload of of type "type" with parameters specified by
+ * "params".  The rank is the caller's relative rank within the collection
+ * of processes that will participate in this workload.   
+ *
+ * This function is intended to be called by a compute node LP in a model
+ * and may be called multiple times over the course of a
+ * simulation in order to execute different application workloads.
+ * 
+ * Returns and identifier that can be used to retrieve operations later.
+ * Returns -1 on failure.
+ */
+int codes_workload_load(const char* type, const char* params, int rank);
+
+/* Retrieves the next I/O operation to execute.  the wkld_id is the
+ * identifier returned by the init() function.  The op argument is a pointer
+ * to a structure to be filled in with I/O operation information.
+ */
+void codes_workload_get_next(int wkld_id, struct codes_workload_op *op);
+
+/* Reverse of the above function. */
+void codes_workload_get_next_rc(int wkld_id, const struct codes_workload_op *op);
+
+/* NOTE: there is deliberately no finalize function; we don't have any
+ * reliable way to tell when a workload is truly done and will not
+ * participate in further reverse computation.   The underlying generators
+ * will shut down automatically once they have issued their last event.
+ */
+
+#endif /* CODES_WORKLOAD_H */
+
+/*
+ * Local variables:
+ *  c-indent-level: 4
+ *  c-basic-offset: 4
+ * End:
+ *
+ * vim: ft=c ts=8 sts=4 sw=4 expandtab
+ */

src/workload/codes-workload-method.h

+/*
+ * Copyright (C) 2013 University of Chicago.
+ * See COPYRIGHT notice in top-level directory.
+ *
+ */
+
+/* I/O workload generator API to be used by workload generators.  It mimics
+ * the top level codes-workload.h API, except that there is no reverse
+ * handler.
+ */
+
+#ifndef CODES_WORKLOAD_METHOD_H
+#define CODES_WORKLOAD_METHOD_H
+
+#include "ross.h"
+#include "codes/codes-workload.h"
+
+int codes_workload_load(const char* type, const char* params, int rank);
+
+void codes_workload_get_next(int wkld_id, struct codes_workload_op *op);
+
+#endif /* CODES_WORKLOAD_METHOD_H */
+
+/*
+ * Local variables:
+ *  c-indent-level: 4
+ *  c-basic-offset: 4
+ * End:
+ *
+ * vim: ft=c ts=8 sts=4 sw=4 expandtab
+ */

src/workload/codes-workload.c

+/*
+ * Copyright (C) 2013 University of Chicago.
+ * See COPYRIGHT notice in top-level directory.
+ *
+ */
+
+
+#include "ross.h"
+#include "codes/codes-workload.h"
+#include "codes-workload-method.h"
+
+int codes_workload_load(const char* type, const char* params, int rank)
+{
+    return(-1);
+}
+
+void codes_workload_get_next(int wkld_id, struct codes_workload_op *op)
+{
+    return;
+}
+
+void codes_workload_get_next_rc(int wkld_id, const struct codes_workload_op *op)
+{
+    return;
+}
+
+/*
+ * Local variables:
+ *  c-indent-level: 4
+ *  c-basic-offset: 4
+ * End:
+ *
+ * vim: ft=c ts=8 sts=4 sw=4 expandtab
+ */