Feedback control module API updated to its new version as proposed by SSSA.

git-svn-id: http://www.frescor.org/private/svn/frescor/frsh/trunk/include@969 35b4ef3e-fd22-0410-ab77-dab3279adceb

diff --git a/frsh_feedback_control.h b/frsh_feedback_control.h
index 165c1f23c1c08e67718a4def228acc7dece8b983..f1df01d3bb57288e3af7385010869485b80e0a64 100644 (file)
--- a/frsh_feedback_control.h
+++ b/frsh_feedback_control.h
@@ -76,7 +76,7 @@
 #include <time.h>
 
 #include "frsh_fosa.h"
-#include "frsh_feedback_control_types.h"
+//#include "frsh_feedback_control_types.h"
 #include "frsh_core_types.h"
 
 
@@ -92,30 +92,120 @@
  * This module provides a way to implement a QoS manager at the
  * application level.
  *
+ * @note
+ * Please, note that, in order to exploit the feedback-scheduling
+ * functionality of FRESCOR, an application needs to use a set of
+ * different functions:
+ * <ul>
+ *   <li>the frsh_contract_set_basic_params() and the
+ *       frsh_contract_set_reclamation_params() functions are used
+ *       to set the dynamic variability range (or options) for the budget;
+ *   <li>the frsh_feedback_set_spare() function is used to communicate to
+ *       the FMGR module what is the spare virtual resource that is used
+ *       to reserve a fraction of resource availability by FMGR-enabled
+ *       applications, so to avoid a complete occupation of the system
+ *       (this is needed in common cases if one wants to keep a good
+ *       performance of the QoS control loops);
+ *       such spare vres needs to have been previously negotiated through
+ *       the usual functions in the FRSH Core module;
+ *   <li>the frsh_feedback_set_desired_budget() function is used to
+ *       dynamically fine-tune the budget request for the application,
+ *       leaving to the FMGR module the freedom to fulfill the requests
+ *       made by all the applications in the system according to global
+ *       QoS control goals, as well as to the importance and weight
+ *       parameters that may be specified by the applications for individual
+ *       virtual resources.
+ * </ul>
+ *
  * @{
  *
  **/
 
-
-
 /**
- * frsh_feedback_reserve()
+ * frsh_feedback_set_spare()
  *
- * This function reserves a portion of spare space to be distributed
- * among the vres with this method.
+ * This function is used to tell the FRSH FEEDBACKCTRL module what is
+ * the spare contract that is used as a "reserve" of computation
+ * resources that may be used by other contracts making use of adaptive
+ * reservations.
+ *
+ * @note
+ * No threads must be ever attached to the contract identified by
+ * spare_id.
  **/
-int frsh_feedback_reserve(frsh_spare_subset_t utilization);
+int frsh_feedback_set_spare(const frsh_contract_t *spare_contract);
 
+/**
+ * frsh_feedback_get_spare()
+ *
+ * Get version of the frsh_feedback_set_spare() function.
+ **/
+int frsh_feedback_get_spare(frsh_contract_t *spare_contract);
 
+/**
+ * frsh_feedback_set_desired_budget()
+ *
+ * This function sets the budget request that would best suite the
+ * needs of the application for the very next server periods. The
+ * budget actually used for the vres instances (application jobs),
+ * that may be retrieved through a frsh_feedback_get_actual_budget() call,
+ * is dynamically changed by the FMGR Module, and may be less than
+ * the required value, as due to the following rules:
+ *
+ * <ul>
+ *   <li>if the required budget is less than the minimum guaranteed
+ *       negotiated for the vres, then it is always granted;
+ *   <li>if the set of requested budgets is schedulable, then all the
+ *       requests are granted, except for what stated in the note below;
+ *   <li>if the set of requested budgets overcomes the resource capacity
+ *       and the required budget is higher than the minimum guaranteed
+ *       negotiated for the vres, then the FMGR module makes an attempt to
+ *       fulfill the application request by using also the spare computation
+ *       resources that have been reserved through the
+ *       frsh_feedback_set_spare() call.
+ * </ul>
+ *
+ * Before any frsh_feedback_set_desired_budget() call, the desired budget
+ * is assumed to be equal to the maximum budget value set during contract
+ * negotiation.
+ *
+ * @note
+ * If the requested budget is higher than the maximum value negotiated
+ * for the vres, then an error is returned.
+ *
+ * @note
+ * The actual budget that is used for a vres may change dynamically
+ * and asynchronously with respect to the threads attached to the vres,
+ * due to other contracts being negotiated, renegotiated or terminated,
+ * or due the call of the frsh_feedback_set_desired_budget() function
+ * for other virtual resources.
+ *
+ * @param[in] p_budget_in
+ * The new budget to set as desired.
+ **/
+int frsh_feedback_set_desired_budget(frsh_vres_id_t vres_id, struct timespec *p_budget_in);
 
 /**
- * frsh_vres_set_next_budget()
+ * frsh_feedback_get_desired_budget()
  *
- * This function reserves a portion of spare space to be distributed
- * among the vres with this method.
+ * Get version of the frsh_feedback_set_desired_budget() function.
+ *
+ * @param[out] p_budget_out
+ * The last budget set as desired through a frsh_feedback_set_desired_budget()
+ * call, or the maximum budget set during contract negotiation, if no such
+ * call ever occurred.
  **/
-int frsh_vres_set_next_budget(frsh_vres_id_t vres_id, struct timespec new_budget);
+int frsh_feedback_get_desired_budget(frsh_vres_id_t vres_id, struct timespec *p_budget_out);
 
+/**
+ * frsh_feedback_get_actual_budget()
+ *
+ * Retrieve the actual budget that is being dynamically used by the FMGR module for
+ * the specified vres. The value returned by this function (in the budget parameter)
+ * for a given vres may change dynamically as a result of a call to the
+ * frsh_feedback_set_desired_budget() function for the same or other virtual resources.
+ **/
+int frsh_feedback_get_actual_budget(frsh_vres_id_t vres_id, struct timespec *budget);
 
 /*@}*/