X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=src%2Ftestbed%2Ftestbed_api_operations.c;h=de24517d6a959c2eba983f2c749880707a21aa05;hb=f40acfa927bb605c81c99ed250277d51bf951e25;hp=5758e2aa9a4f366bec5fcf9ef881b5d2f03c6bcf;hpb=e8e09d1eab1492ee4676aadbfb047386c3ccd466;p=oweals%2Fgnunet.git

diff --git a/src/testbed/testbed_api_operations.c b/src/testbed/testbed_api_operations.c
index 5758e2aa9..de24517d6 100644
--- a/src/testbed/testbed_api_operations.c
+++ b/src/testbed/testbed_api_operations.c
@@ -1,6 +1,6 @@
 /*
       This file is part of GNUnet
-      (C) 2008--2012 Christian Grothoff (and other contributing authors)
+      Copyright (C) 2008--2013 GNUnet e.V.
 
       GNUnet is free software; you can redistribute it and/or modify
       it under the terms of the GNU General Public License as published
@@ -14,18 +14,32 @@
 
       You should have received a copy of the GNU General Public License
       along with GNUnet; see the file COPYING.  If not, write to the
-      Free Software Foundation, Inc., 59 Temple Place - Suite 330,
-      Boston, MA 02111-1307, USA.
+      Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+      Boston, MA 02110-1301, USA.
  */
 
 /**
  * @file testbed/testbed_api_operations.c
  * @brief functions to manage operation queues
  * @author Christian Grothoff
+ * @author Sree Harsha Totakura
  */
+
 #include "platform.h"
 #include "testbed_api_operations.h"
+#include "testbed_api_sd.h"
+
+/**
+ * The number of readings containing past operation's timing information that we
+ * keep track of for adaptive queues
+ */
+#define ADAPTIVE_QUEUE_DEFAULT_HISTORY 40
 
+/**
+ * The number of parallel opeartions we start with by default for adaptive
+ * queues
+ */
+#define ADAPTIVE_QUEUE_DEFAULT_MAX_ACTIVE 4
 
 /**
  * An entry in the operation queue
@@ -46,6 +60,98 @@ struct QueueEntry
    * The operation this entry holds
    */
   struct GNUNET_TESTBED_Operation *op;
+
+  /**
+   * How many units of resources does the operation need
+   */
+  unsigned int nres;
+};
+
+
+/**
+ * Queue of operations where we can only support a certain
+ * number of concurrent operations of a particular type.
+ */
+struct OperationQueue;
+
+
+/**
+ * A slot to record time taken by an operation
+ */
+struct TimeSlot
+{
+  /**
+   * DLL next pointer
+   */
+  struct TimeSlot *next;
+
+  /**
+   * DLL prev pointer
+   */
+  struct TimeSlot *prev;
+
+  /**
+   * This operation queue to which this time slot belongs to
+   */
+  struct OperationQueue *queue;
+
+  /**
+   * The operation to which this timeslot is currently allocated to
+   */
+  struct GNUNET_TESTBED_Operation *op;
+
+  /**
+   * Accumulated time
+   */
+  struct GNUNET_TIME_Relative tsum;
+
+  /**
+   * Number of timing values accumulated
+   */
+  unsigned int nvals;
+};
+
+
+/**
+ * Context for operation queues of type OPERATION_QUEUE_TYPE_ADAPTIVE
+ */
+struct FeedbackCtx
+{
+  /**
+   * Handle for calculating standard deviation
+   */
+  struct SDHandle *sd;
+
+  /**
+   * Head for DLL of time slots which are free to be allocated to operations
+   */
+  struct TimeSlot *alloc_head;
+
+  /**
+   * Tail for DLL of time slots which are free to be allocated to operations
+   */
+  struct TimeSlot *alloc_tail;
+
+  /**
+   * Pointer to the chunk of time slots.  Free all time slots at a time using
+   * this pointer.
+   */
+  struct TimeSlot *tslots_freeptr;
+
+  /**
+   * Number of time slots filled so far
+   */
+  unsigned int tslots_filled;
+
+  /**
+   * Bound on the maximum number of operations which can be active
+   */
+  unsigned int max_active_bound;
+
+  /**
+   * Number of operations that have failed
+   */
+  unsigned int nfailed;
 };
 
 
@@ -55,38 +161,144 @@ struct QueueEntry
  */
 struct OperationQueue
 {
- /**
-   * The head of the operation queue
+  /**
+   * DLL head for the wait queue.  Operations which are waiting for this
+   * operation queue are put here
+   */
+  struct QueueEntry *wq_head;
+
+  /**
+   * DLL tail for the wait queue.
+   */
+  struct QueueEntry *wq_tail;
+
+  /**
+   * DLL head for the ready queue.  Operations which are in this operation queue
+   * and are in ready state are put here
+   */
+  struct QueueEntry *rq_head;
+
+  /**
+   * DLL tail for the ready queue
+   */
+  struct QueueEntry *rq_tail;
+
+  /**
+   * DLL head for the active queue.  Operations which are in this operation
+   * queue and are currently active are put here
+   */
+  struct QueueEntry *aq_head;
+
+  /**
+   * DLL tail for the active queue.
    */
-  struct QueueEntry *head;
+  struct QueueEntry *aq_tail;
 
   /**
-   * The tail of the operation queue
+   * DLL head for the inactive queue.  Operations which are inactive and can be
+   * evicted if the queues it holds are maxed out and another operation begins
+   * to wait on them.
    */
-  struct QueueEntry *tail;
+  struct QueueEntry *nq_head;
 
   /**
-   * Number of operations that can be concurrently
-   * active in this queue.
+   * DLL tail for the inactive queue.
    */
-  unsigned int active;  
+  struct QueueEntry *nq_tail;
+
+  /**
+   * Feedback context; only relevant for adaptive operation queues.  NULL for
+   * fixed operation queues
+   */
+  struct FeedbackCtx *fctx;
+
+  /**
+   * The type of this opeartion queue
+   */
+  enum OperationQueueType type;
+
+  /**
+   * Number of operations that are currently active in this queue.
+   */
+  unsigned int active;
+
+  /**
+   * Max number of operations which can be active at any time in this queue.
+   * This value can be changed either by calling
+   * GNUNET_TESTBED_operation_queue_reset_max_active_() or by the adaptive
+   * algorithm if this operation queue is of type #OPERATION_QUEUE_TYPE_ADAPTIVE
+   */
+  unsigned int max_active;
+
+  /**
+   * The number of resources occupied by failed operations in the current shot.
+   * This is only relavant if the operation queue is of type
+   * #OPERATION_QUEUE_TYPE_ADAPTIVE
+   */
+  unsigned int overload;
+
+  /**
+   * Is this queue marked for expiry?
+   */
+  unsigned int expired;
 };
 
 
+/**
+ * Operation state
+ */
 enum OperationState
-  {
-    /**
-     * The operation is currently waiting for resources
-     */
-    OP_STATE_WAITING,
+{
+  /**
+   * The operation is just created and is in initial state
+   */
+  OP_STATE_INIT,
+
+  /**
+   * The operation is currently waiting for resources
+   */
+  OP_STATE_WAITING,
+
+  /**
+   * The operation is ready to be started
+   */
+  OP_STATE_READY,
+
+  /**
+   * The operation has started and is active
+   */
+  OP_STATE_ACTIVE,
+
+  /**
+   * The operation is inactive.  It still holds resources on the operation
+   * queues.  However, this operation will be evicted when another operation
+   * requires resources from the maxed out queues this operation is holding
+   * resources from.
+   */
+  OP_STATE_INACTIVE
+};
 
-    /**
-     * The operation has started
-     */
-    OP_STATE_STARTED,
-  };
 
-  
+/**
+ * An entry in the ready queue (implemented as DLL)
+ */
+struct ReadyQueueEntry
+{
+  /**
+   * next ptr for DLL
+   */
+  struct ReadyQueueEntry *next;
+
+  /**
+   * prev ptr for DLL
+   */
+  struct ReadyQueueEntry *prev;
+
+  /**
+   * The operation associated with this entry
+   */
+  struct GNUNET_TESTBED_Operation *op;
+};
 
 
 /**
@@ -104,7 +316,7 @@ struct GNUNET_TESTBED_Operation
    * not have been started yet).
    */
   OperationRelease release;
-				 
+
   /**
    * Closure for callbacks.
    */
@@ -116,9 +328,37 @@ struct GNUNET_TESTBED_Operation
   struct OperationQueue **queues;
 
   /**
-   * The id of the task which calls OperationStart for this operation
+   * Array of operation queue entries corresponding to this operation in
+   * operation queues for this operation
+   */
+  struct QueueEntry **qentries;
+
+  /**
+   * Array of number of resources an operation need from each queue. The numbers
+   * in this array should correspond to the queues array
+   */
+  unsigned int *nres;
+
+  /**
+   * Entry corresponding to this operation in ready queue.  Will be NULL if the
+   * operation is not marked as READY
+   */
+  struct ReadyQueueEntry *rq_entry;
+
+  /**
+   * Head pointer for DLL of tslots allocated to this operation
+   */
+  struct TimeSlot *tslots_head;
+
+  /**
+   * Tail pointer for DLL of tslots allocated to this operation
+   */
+  struct TimeSlot *tslots_tail;
+
+  /**
+   * The time at which the operation is started
    */
-  GNUNET_SCHEDULER_TaskIdentifier start_task_id;
+  struct GNUNET_TIME_Absolute tstart;
 
   /**
    * Number of queues in the operation queues array
@@ -128,52 +368,644 @@ struct GNUNET_TESTBED_Operation
   /**
    * The state of the operation
    */
-  enum OperationState state;  
-  
+  enum OperationState state;
+
+  /**
+   * Is this a failed operation?
+   */
+  int failed;
+
 };
 
+/**
+ * DLL head for the ready queue
+ */
+static struct ReadyQueueEntry *rq_head;
+
+/**
+ * DLL tail for the ready queue
+ */
+static struct ReadyQueueEntry *rq_tail;
+
+/**
+ * Array of operation queues which are to be destroyed
+ */
+static struct OperationQueue **expired_opqs;
+
+/**
+ * Number of expired operation queues in the above array
+ */
+static unsigned int n_expired_opqs;
 
 /**
- * Task for calling OperationStart on operation
+ * The id of the task to process the ready queue
+ */
+struct GNUNET_SCHEDULER_Task *process_rq_task_id;
+
+
+/**
+ * Assigns the given operation a time slot from the given operation queue
  *
- * @param cls the Operation
- * @param tc the TaskContext from scheduler
+ * @param op the operation
+ * @param queue the operation queue
+ * @return the timeslot
  */
 static void
-call_start (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
-{  
-  struct GNUNET_TESTBED_Operation *op = cls;
-  
-  op->start_task_id = GNUNET_SCHEDULER_NO_TASK;
-  op->state = OP_STATE_STARTED;
-  if (NULL != op->start)
+assign_timeslot (struct GNUNET_TESTBED_Operation *op,
+                 struct OperationQueue *queue)
+{
+  struct FeedbackCtx *fctx = queue->fctx;
+  struct TimeSlot *tslot;
+
+  GNUNET_assert (OPERATION_QUEUE_TYPE_ADAPTIVE == queue->type);
+  tslot = fctx->alloc_head;
+  GNUNET_assert (NULL != tslot);
+  GNUNET_CONTAINER_DLL_remove (fctx->alloc_head, fctx->alloc_tail, tslot);
+  GNUNET_CONTAINER_DLL_insert_tail (op->tslots_head, op->tslots_tail, tslot);
+  tslot->op = op;
+}
+
+
+/**
+ * Removes a queue entry of an operation from one of the operation queues' lists
+ * depending on the state of the operation
+ *
+ * @param op the operation whose entry has to be removed
+ * @param index the index of the entry in the operation's array of queue entries
+ */
+static void
+remove_queue_entry (struct GNUNET_TESTBED_Operation *op, unsigned int index)
+{
+  struct OperationQueue *opq;
+  struct QueueEntry *entry;
+
+  opq = op->queues[index];
+  entry = op->qentries[index];
+  switch (op->state)
+  {
+  case OP_STATE_INIT:
+    GNUNET_assert (0);
+    break;
+  case OP_STATE_WAITING:
+    GNUNET_CONTAINER_DLL_remove (opq->wq_head, opq->wq_tail, entry);
+    break;
+  case OP_STATE_READY:
+    GNUNET_CONTAINER_DLL_remove (opq->rq_head, opq->rq_tail, entry);
+    break;
+  case OP_STATE_ACTIVE:
+    GNUNET_CONTAINER_DLL_remove (opq->aq_head, opq->aq_tail, entry);
+    break;
+  case OP_STATE_INACTIVE:
+    GNUNET_CONTAINER_DLL_remove (opq->nq_head, opq->nq_tail, entry);
+    break;
+  }
+}
+
+
+/**
+ * Changes the state of the operation while moving its associated queue entries
+ * in the operation's operation queues
+ *
+ * @param op the operation whose state has to be changed
+ * @param state the state the operation should have.  It cannot be OP_STATE_INIT
+ */
+static void
+change_state (struct GNUNET_TESTBED_Operation *op, enum OperationState state)
+{
+  struct QueueEntry *entry;
+  struct OperationQueue *opq;
+  unsigned int cnt;
+  unsigned int s;
+
+  GNUNET_assert (OP_STATE_INIT != state);
+  GNUNET_assert (NULL != op->queues);
+  GNUNET_assert (NULL != op->nres);
+  GNUNET_assert ((OP_STATE_INIT == op->state) || (NULL != op->qentries));
+  GNUNET_assert (op->state != state);
+  for (cnt = 0; cnt < op->nqueues; cnt++)
   {
+    if (OP_STATE_INIT == op->state)
+    {
+      entry = GNUNET_new (struct QueueEntry);
+      entry->op = op;
+      entry->nres = op->nres[cnt];
+      s = cnt;
+      GNUNET_array_append (op->qentries, s, entry);
+    }
+    else
+    {
+      entry = op->qentries[cnt];
+      remove_queue_entry (op, cnt);
+    }
+    opq = op->queues[cnt];
+    switch (state)
+    {
+    case OP_STATE_INIT:
+      GNUNET_assert (0);
+      break;
+    case OP_STATE_WAITING:
+      GNUNET_CONTAINER_DLL_insert_tail (opq->wq_head, opq->wq_tail, entry);
+      break;
+    case OP_STATE_READY:
+      GNUNET_CONTAINER_DLL_insert_tail (opq->rq_head, opq->rq_tail, entry);
+      break;
+    case OP_STATE_ACTIVE:
+      GNUNET_CONTAINER_DLL_insert_tail (opq->aq_head, opq->aq_tail, entry);
+      break;
+    case OP_STATE_INACTIVE:
+      GNUNET_CONTAINER_DLL_insert_tail (opq->nq_head, opq->nq_tail, entry);
+      break;
+    }
+  }
+  op->state = state;
+}
+
+
+/**
+ * Removes an operation from the ready queue.  Also stops the 'process_rq_task'
+ * if the given operation is the last one in the queue.
+ *
+ * @param op the operation to be removed
+ */
+static void
+rq_remove (struct GNUNET_TESTBED_Operation *op)
+{
+  GNUNET_assert (NULL != op->rq_entry);
+  GNUNET_CONTAINER_DLL_remove (rq_head, rq_tail, op->rq_entry);
+  GNUNET_free (op->rq_entry);
+  op->rq_entry = NULL;
+  if ( (NULL == rq_head) && (NULL != process_rq_task_id) )
+  {
+    GNUNET_SCHEDULER_cancel (process_rq_task_id);
+    process_rq_task_id = NULL;
+  }
+}
+
+
+/**
+ * Processes the ready queue by calling the operation start callback of the
+ * operation at the head.  The operation is then removed from the queue.  The
+ * task is scheduled to run again immediately until no more operations are in
+ * the ready queue.
+ *
+ * @param cls NULL
+ */
+static void
+process_rq_task (void *cls)
+{
+  struct GNUNET_TESTBED_Operation *op;
+  struct OperationQueue *queue;
+  unsigned int cnt;
+
+  process_rq_task_id = NULL;
+  GNUNET_assert (NULL != rq_head);
+  GNUNET_assert (NULL != (op = rq_head->op));
+  rq_remove (op);
+  if (NULL != rq_head)
+    process_rq_task_id = GNUNET_SCHEDULER_add_now (&process_rq_task, NULL);
+  change_state (op, OP_STATE_ACTIVE);
+  for (cnt = 0; cnt < op->nqueues; cnt++)
+  {
+    queue = op->queues[cnt];
+    if (OPERATION_QUEUE_TYPE_ADAPTIVE == queue->type)
+      assign_timeslot (op, queue);
+  }
+  op->tstart = GNUNET_TIME_absolute_get ();
+  if (NULL != op->start)
     op->start (op->cb_cls);
-  }  
 }
 
 
+/**
+ * Adds the operation to the ready queue and starts the 'process_rq_task'
+ *
+ * @param op the operation to be queued
+ */
+static void
+rq_add (struct GNUNET_TESTBED_Operation *op)
+{
+  struct ReadyQueueEntry *rq_entry;
+
+  GNUNET_assert (NULL == op->rq_entry);
+  rq_entry = GNUNET_new (struct ReadyQueueEntry);
+  rq_entry->op = op;
+  GNUNET_CONTAINER_DLL_insert_tail (rq_head, rq_tail, rq_entry);
+  op->rq_entry = rq_entry;
+  if (NULL == process_rq_task_id)
+    process_rq_task_id = GNUNET_SCHEDULER_add_now (&process_rq_task, NULL);
+}
+
+
+/**
+ * Checks if the given operation queue is empty or not
+ *
+ * @param opq the operation queue
+ * @return GNUNET_YES if the given operation queue has no operations; GNUNET_NO
+ *           otherwise
+ */
+static int
+is_queue_empty (struct OperationQueue *opq)
+{
+  if ( (NULL != opq->wq_head)
+       || (NULL != opq->rq_head)
+       || (NULL != opq->aq_head)
+       || (NULL != opq->nq_head) )
+    return GNUNET_NO;
+  return GNUNET_YES;
+}
+
+
+/**
+ * Checks if the given operation queue has enough resources to provide for the
+ * operation of the given queue entry.  It also checks if any inactive
+ * operations are to be released in order to accommodate the needed resources
+ * and returns them as an array.
+ *
+ * @param opq the operation queue to check for resource accommodation
+ * @param entry the operation queue entry whose operation's resources are to be
+ *          accommodated
+ * @param ops_ pointer to return the array of operations which are to be released
+ *          in order to accommodate the new operation.  Can be NULL
+ * @param n_ops_ the number of operations in ops_
+ * @return GNUNET_YES if the given entry's operation can be accommodated in this
+ *           queue. GNUNET_NO if it cannot be accommodated; ops_ and n_ops_ will
+ *           be set to NULL and 0 respectively.
+ */
+static int
+decide_capacity (struct OperationQueue *opq,
+                 struct QueueEntry *entry,
+                 struct GNUNET_TESTBED_Operation ***ops_,
+                 unsigned int *n_ops_)
+{
+  struct QueueEntry **evict_entries;
+  struct GNUNET_TESTBED_Operation **ops;
+  struct GNUNET_TESTBED_Operation *op;
+  unsigned int n_ops;
+  unsigned int n_evict_entries;
+  unsigned int need;
+  unsigned int max;
+  int deficit;
+  int rval;
+
+  GNUNET_assert (NULL != (op = entry->op));
+  GNUNET_assert (0 < (need = entry->nres));
+  ops = NULL;
+  n_ops = 0;
+  evict_entries = NULL;
+  n_evict_entries = 0;
+  rval = GNUNET_YES;
+  if (OPERATION_QUEUE_TYPE_ADAPTIVE == opq->type)
+  {
+    GNUNET_assert (NULL != opq->fctx);
+    GNUNET_assert (opq->max_active >= opq->overload);
+    max = opq->max_active - opq->overload;
+  }
+  else
+    max = opq->max_active;
+  if (opq->active > max)
+  {
+    rval = GNUNET_NO;
+    goto ret;
+  }
+  if ((opq->active + need) <= max)
+    goto ret;
+  deficit = need - (max - opq->active);
+  for (entry = opq->nq_head;
+       (0 < deficit) && (NULL != entry);
+       entry = entry->next)
+  {
+    GNUNET_array_append (evict_entries, n_evict_entries, entry);
+    deficit -= entry->nres;
+  }
+  if (0 < deficit)
+  {
+    rval = GNUNET_NO;
+    goto ret;
+  }
+  for (n_ops = 0; n_ops < n_evict_entries;)
+  {
+    op = evict_entries[n_ops]->op;
+    GNUNET_array_append (ops, n_ops, op); /* increments n-ops */
+  }
+
+ ret:
+  GNUNET_free_non_null (evict_entries);
+  if (NULL != ops_)
+    *ops_ = ops;
+  else
+    GNUNET_free (ops);
+  if (NULL != n_ops_)
+    *n_ops_ = n_ops;
+  return rval;
+}
+
+
+/**
+ * Merges an array of operations into another, eliminating duplicates.  No
+ * ordering is guaranteed.
+ *
+ * @param old the array into which the merging is done.
+ * @param n_old the number of operations in old array
+ * @param new the array from which operations are to be merged
+ * @param n_new the number of operations in new array
+ */
+static void
+merge_ops (struct GNUNET_TESTBED_Operation ***old,
+           unsigned int *n_old,
+           struct GNUNET_TESTBED_Operation **new,
+           unsigned int n_new)
+{
+  struct GNUNET_TESTBED_Operation **cur;
+  unsigned int i;
+  unsigned int j;
+  unsigned int n_cur;
+
+  GNUNET_assert (NULL != old);
+  n_cur = *n_old;
+  cur = *old;
+  for (i = 0; i < n_new; i++)
+  {
+    for (j = 0; j < *n_old; j++)
+    {
+      if (new[i] == cur[j])
+        break;
+    }
+    if (j < *n_old)
+      continue;
+    GNUNET_array_append (cur, n_cur, new[j]);
+  }
+  *old = cur;
+  *n_old = n_cur;
+}
+
+
+
 /**
  * Checks for the readiness of an operation and schedules a operation start task
  *
  * @param op the operation
  */
-static void
+static int
 check_readiness (struct GNUNET_TESTBED_Operation *op)
-{   
+{
+  struct GNUNET_TESTBED_Operation **evict_ops;
+  struct GNUNET_TESTBED_Operation **ops;
+  unsigned int n_ops;
+  unsigned int n_evict_ops;
   unsigned int i;
-  
+
+  GNUNET_assert (NULL == op->rq_entry);
+  GNUNET_assert (OP_STATE_WAITING == op->state);
+  evict_ops = NULL;
+  n_evict_ops = 0;
   for (i = 0; i < op->nqueues; i++)
   {
-    if (0 == op->queues[i]->active)
-      return;
+    ops = NULL;
+    n_ops = 0;
+    if (GNUNET_NO == decide_capacity (op->queues[i], op->qentries[i],
+                                      &ops, &n_ops))
+    {
+      GNUNET_free_non_null (evict_ops);
+      return GNUNET_NO;
+    }
+    if (NULL == ops)
+      continue;
+    merge_ops (&evict_ops, &n_evict_ops, ops, n_ops);
+    GNUNET_free (ops);
+  }
+  if (NULL != evict_ops)
+  {
+    for (i = 0; i < n_evict_ops; i++)
+      GNUNET_TESTBED_operation_release_ (evict_ops[i]);
+    GNUNET_free (evict_ops);
+    evict_ops = NULL;
+    /* Evicting the operations should schedule this operation */
+    GNUNET_assert (OP_STATE_READY == op->state);
+    return GNUNET_YES;
   }
   for (i = 0; i < op->nqueues; i++)
+    op->queues[i]->active += op->nres[i];
+  change_state (op, OP_STATE_READY);
+  rq_add (op);
+  return GNUNET_YES;
+}
+
+
+/**
+ * Defers a ready to be executed operation back to waiting
+ *
+ * @param op the operation to defer
+ */
+static void
+defer (struct GNUNET_TESTBED_Operation *op)
+{
+  unsigned int i;
+
+  GNUNET_assert (OP_STATE_READY == op->state);
+  rq_remove (op);
+  for (i = 0; i < op->nqueues; i++)
+  {
+    GNUNET_assert (op->queues[i]->active >= op->nres[i]);
+    op->queues[i]->active -= op->nres[i];
+  }
+  change_state (op, OP_STATE_WAITING);
+}
+
+
+/**
+ * Cleanups the array of timeslots of an operation queue.  For each time slot in
+ * the array, if it is allocated to an operation, it will be deallocated from
+ * the operation
+ *
+ * @param queue the operation queue
+ */
+static void
+cleanup_tslots (struct OperationQueue *queue)
+{
+  struct FeedbackCtx *fctx = queue->fctx;
+  struct TimeSlot *tslot;
+  struct GNUNET_TESTBED_Operation *op;
+  unsigned int cnt;
+
+  GNUNET_assert (NULL != fctx);
+  for (cnt = 0; cnt < queue->max_active; cnt++)
+  {
+    tslot = &fctx->tslots_freeptr[cnt];
+    op = tslot->op;
+    if (NULL == op)
+      continue;
+    GNUNET_CONTAINER_DLL_remove (op->tslots_head, op->tslots_tail, tslot);
+  }
+  GNUNET_free_non_null (fctx->tslots_freeptr);
+  fctx->tslots_freeptr = NULL;
+  fctx->alloc_head = NULL;
+  fctx->alloc_tail = NULL;
+  fctx->tslots_filled = 0;
+}
+
+
+/**
+ * Cleansup the existing timing slots and sets new timing slots in the given
+ * queue to accommodate given number of max active operations.
+ *
+ * @param queue the queue
+ * @param n the number of maximum active operations.  If n is greater than the
+ *   maximum limit set while creating the queue, then the minimum of these two
+ *   will be selected as n
+ */
+static void
+adaptive_queue_set_max_active (struct OperationQueue *queue, unsigned int n)
+{
+  struct FeedbackCtx *fctx = queue->fctx;
+  struct TimeSlot *tslot;
+  unsigned int cnt;
+
+  cleanup_tslots (queue);
+  n = GNUNET_MIN (n ,fctx->max_active_bound);
+  fctx->tslots_freeptr = GNUNET_malloc (n * sizeof (struct TimeSlot));
+  fctx->nfailed = 0;
+  for (cnt = 0; cnt < n; cnt++)
   {
-    op->queues[i]->active--;
+    tslot = &fctx->tslots_freeptr[cnt];
+    tslot->queue = queue;
+    GNUNET_CONTAINER_DLL_insert_tail (fctx->alloc_head, fctx->alloc_tail, tslot);
+  }
+  GNUNET_TESTBED_operation_queue_reset_max_active_ (queue, n);
+}
+
+
+/**
+ * Adapts parallelism in an adaptive queue by using the statistical data from
+ * the feedback context.
+ *
+ * @param queue the queue
+ */
+static void
+adapt_parallelism (struct OperationQueue *queue)
+{
+  struct GNUNET_TIME_Relative avg;
+  struct FeedbackCtx *fctx;
+  struct TimeSlot *tslot;
+  int sd;
+  unsigned int nvals;
+  unsigned int cnt;
+  unsigned int parallelism;
+
+  avg = GNUNET_TIME_UNIT_ZERO;
+  nvals = 0;
+  fctx = queue->fctx;
+  for (cnt = 0; cnt < queue->max_active; cnt++)
+  {
+    tslot = &fctx->tslots_freeptr[cnt];
+    avg = GNUNET_TIME_relative_add (avg, tslot->tsum);
+    nvals += tslot->nvals;
+  }
+  GNUNET_assert (nvals >= queue->max_active);
+  GNUNET_assert (fctx->nfailed <= nvals);
+  nvals -= fctx->nfailed;
+  if (0 == nvals)
+  {
+    if (1 == queue->max_active)
+      adaptive_queue_set_max_active (queue, 1);
+    else
+      adaptive_queue_set_max_active (queue, queue->max_active / 2);
+    return;
+  }
+  avg = GNUNET_TIME_relative_divide (avg, nvals);
+  GNUNET_TESTBED_SD_add_data_ (fctx->sd, (unsigned int) avg.rel_value_us);
+  if (GNUNET_SYSERR ==
+      GNUNET_TESTBED_SD_deviation_factor_ (fctx->sd,
+                                           (unsigned int) avg.rel_value_us,
+                                           &sd))
+  {
+    adaptive_queue_set_max_active (queue, queue->max_active); /* no change */
+    return;
+  }
+
+  parallelism = 0;
+  if (-1 == sd)
+    parallelism = queue->max_active + 1;
+  if (sd <= -2)
+    parallelism = queue->max_active * 2;
+  if (1 == sd)
+    parallelism = queue->max_active - 1;
+  if (2 <= sd)
+    parallelism = queue->max_active / 2;
+  parallelism = GNUNET_MAX (parallelism, ADAPTIVE_QUEUE_DEFAULT_MAX_ACTIVE);
+  adaptive_queue_set_max_active (queue, parallelism);
+
+#if 0
+  /* old algorithm */
+  if (sd < 0)
+    sd = 0;
+  GNUNET_assert (0 <= sd);
+  //GNUNET_TESTBED_SD_add_data_ (fctx->sd, (unsigned int) avg.rel_value_us);
+  if (0 == sd)
+  {
+    adaptive_queue_set_max_active (queue, queue->max_active * 2);
+    return;
+  }
+  if (1 == sd)
+  {
+    adaptive_queue_set_max_active (queue, queue->max_active + 1);
+    return;
+  }
+  if (1 == queue->max_active)
+  {
+    adaptive_queue_set_max_active (queue, 1);
+    return;
+  }
+  if (2 == sd)
+  {
+    adaptive_queue_set_max_active (queue, queue->max_active - 1);
+    return;
+  }
+  adaptive_queue_set_max_active (queue, queue->max_active / 2);
+#endif
+}
+
+
+/**
+ * update tslots with the operation's completion time.  Additionally, if
+ * updating a timeslot makes all timeslots filled in an adaptive operation
+ * queue, call adapt_parallelism() for that queue.
+ *
+ * @param op the operation
+ */
+static void
+update_tslots (struct GNUNET_TESTBED_Operation *op)
+{
+  struct OperationQueue *queue;
+  struct GNUNET_TIME_Relative t;
+  struct TimeSlot *tslot;
+  struct FeedbackCtx *fctx;
+  unsigned int i;
+
+  t = GNUNET_TIME_absolute_get_duration (op->tstart);
+  while (NULL != (tslot = op->tslots_head)) /* update time slots */
+  {
+    queue = tslot->queue;
+    fctx = queue->fctx;
+    GNUNET_CONTAINER_DLL_remove (op->tslots_head, op->tslots_tail, tslot);
+    tslot->op = NULL;
+    GNUNET_CONTAINER_DLL_insert_tail (fctx->alloc_head, fctx->alloc_tail,
+                                      tslot);
+    if (op->failed)
+    {
+      fctx->nfailed++;
+      for (i = 0; i < op->nqueues; i++)
+        if (queue == op->queues[i])
+            break;
+      GNUNET_assert (i != op->nqueues);
+      op->queues[i]->overload += op->nres[i];
+    }
+    tslot->tsum = GNUNET_TIME_relative_add (tslot->tsum, t);
+    if (0 != tslot->nvals++)
+      continue;
+    fctx->tslots_filled++;
+    if (queue->max_active == fctx->tslots_filled)
+      adapt_parallelism (queue);
   }
-  GNUNET_assert (GNUNET_SCHEDULER_NO_TASK == op->start_task_id);
-  op->start_task_id = GNUNET_SCHEDULER_add_now (&call_start, op);  
 }
 
 
@@ -186,113 +1018,265 @@ check_readiness (struct GNUNET_TESTBED_Operation *op)
  * @return handle to the operation
  */
 struct GNUNET_TESTBED_Operation *
-GNUNET_TESTBED_operation_create_ (void *cls,
-				  OperationStart start,
-				  OperationRelease release)
+GNUNET_TESTBED_operation_create_ (void *cls, OperationStart start,
+                                  OperationRelease release)
 {
   struct GNUNET_TESTBED_Operation *op;
 
-  op = GNUNET_malloc (sizeof (struct GNUNET_TESTBED_Operation));
+  op = GNUNET_new (struct GNUNET_TESTBED_Operation);
   op->start = start;
+  op->state = OP_STATE_INIT;
   op->release = release;
   op->cb_cls = cls;
-  return op;  
+  return op;
 }
 
 
 /**
  * Create an operation queue.
  *
+ * @param type the type of operation queue
  * @param max_active maximum number of operations in this
  *        queue that can be active in parallel at the same time
  * @return handle to the queue
  */
 struct OperationQueue *
-GNUNET_TESTBED_operation_queue_create_ (unsigned int max_active)
+GNUNET_TESTBED_operation_queue_create_ (enum OperationQueueType type,
+                                        unsigned int max_active)
 {
   struct OperationQueue *queue;
+  struct FeedbackCtx *fctx;
 
-  queue = GNUNET_malloc (sizeof (struct OperationQueue));
-  queue->active = max_active;
+  queue = GNUNET_new (struct OperationQueue);
+  queue->type = type;
+  if (OPERATION_QUEUE_TYPE_FIXED == type)
+  {
+    queue->max_active = max_active;
+  }
+  else
+  {
+    fctx = GNUNET_new (struct FeedbackCtx);
+    fctx->max_active_bound = max_active;
+    fctx->sd = GNUNET_TESTBED_SD_init_ (ADAPTIVE_QUEUE_DEFAULT_HISTORY);
+    queue->fctx = fctx;
+    adaptive_queue_set_max_active (queue, ADAPTIVE_QUEUE_DEFAULT_MAX_ACTIVE);
+  }
   return queue;
 }
 
 
 /**
- * Destroy an operation queue.  The queue MUST be empty
- * at this time.
+ * Cleanup the given operation queue.
+ *
+ * @param queue the operation queue to destroy
+ */
+static void
+queue_destroy (struct OperationQueue *queue)
+{
+  struct FeedbackCtx *fctx;
+
+  if (OPERATION_QUEUE_TYPE_ADAPTIVE == queue->type)
+  {
+    cleanup_tslots (queue);
+    fctx = queue->fctx;
+    GNUNET_TESTBED_SD_destroy_ (fctx->sd);
+    GNUNET_free (fctx);
+  }
+  GNUNET_free (queue);
+}
+
+
+/**
+ * Destroys an operation queue.  If the queue is still in use by operations it
+ * is marked as expired and its resources are released in the destructor
+ * GNUNET_TESTBED_operations_fini().
  *
  * @param queue queue to destroy
  */
 void
 GNUNET_TESTBED_operation_queue_destroy_ (struct OperationQueue *queue)
 {
-  GNUNET_assert (NULL == queue->head);
-  GNUNET_assert (NULL == queue->tail);
-  GNUNET_free (queue);
+  if (GNUNET_YES != is_queue_empty (queue))
+  {
+    GNUNET_assert (0 == queue->expired); /* Are you calling twice on same queue? */
+    queue->expired = 1;
+    GNUNET_array_append (expired_opqs, n_expired_opqs, queue);
+    return;
+  }
+  queue_destroy (queue);
 }
 
 
 /**
- * Add an operation to a queue.  An operation can be in multiple
- * queues at once.  Once all queues permit the operation to become
- * active, the operation will be activated.  The actual activation
- * will occur in a separate task (thus allowing multiple queue 
- * insertions to be made without having the first one instantly
- * trigger the operation if the first queue has sufficient 
- * resources).
+ * Destroys the operation queue if it is empty.  If not empty return GNUNET_NO.
  *
- * @param queue queue to add the operation to
- * @param operation operation to add to the queue
+ * @param queue the queue to destroy if empty
+ * @return GNUNET_YES if the queue is destroyed.  GNUNET_NO if not (because it
+ *           is not empty)
+ */
+int
+GNUNET_TESTBED_operation_queue_destroy_empty_ (struct OperationQueue *queue)
+{
+  if (GNUNET_NO == is_queue_empty (queue))
+    return GNUNET_NO;
+  GNUNET_TESTBED_operation_queue_destroy_ (queue);
+  return GNUNET_YES;
+}
+
+
+/**
+ * Rechecks if any of the operations in the given operation queue's waiting list
+ * can be made active
+ *
+ * @param opq the operation queue
+ */
+static void
+recheck_waiting (struct OperationQueue *opq)
+{
+  struct QueueEntry *entry;
+  struct QueueEntry *entry2;
+
+  entry = opq->wq_head;
+  while (NULL != entry)
+  {
+    entry2 = entry->next;
+    if (GNUNET_NO == check_readiness (entry->op))
+      break;
+    entry = entry2;
+  }
+}
+
+
+/**
+ * Function to reset the maximum number of operations in the given queue. If
+ * max_active is lesser than the number of currently active operations, the
+ * active operations are not stopped immediately.
+ *
+ * @param queue the operation queue which has to be modified
+ * @param max_active the new maximum number of active operations
  */
 void
-GNUNET_TESTBED_operation_queue_insert_ (struct OperationQueue *queue,
-					struct GNUNET_TESTBED_Operation *operation)
+GNUNET_TESTBED_operation_queue_reset_max_active_ (struct OperationQueue *queue,
+                                                  unsigned int max_active)
 {
   struct QueueEntry *entry;
 
-  entry = GNUNET_malloc (sizeof (struct QueueEntry));
-  entry->op = operation;
-  GNUNET_CONTAINER_DLL_insert_tail (queue->head, queue->tail, entry);
-  operation->queues =
-    GNUNET_realloc (operation->queues,
-                    sizeof (struct OperationQueue *) * (++operation->nqueues));
-  operation->queues[operation->nqueues - 1] = queue;
-  check_readiness (operation);
+  queue->max_active = max_active;
+  queue->overload = 0;
+  while ( (queue->active > queue->max_active)
+          && (NULL != (entry = queue->rq_head)) )
+    defer (entry->op);
+  recheck_waiting (queue);
 }
 
 
 /**
- * Remove an operation from a queue.  This can be because the
- * oeration was active and has completed (and the resources have
- * been released), or because the operation was cancelled and
- * thus scheduling the operation is no longer required.
+ * Add an operation to a queue.  An operation can be in multiple queues at
+ * once. Once the operation is inserted into all the queues
+ * GNUNET_TESTBED_operation_begin_wait_() has to be called to actually start
+ * waiting for the operation to become active.
  *
  * @param queue queue to add the operation to
- * @param operation operation to add to the queue
+ * @param op operation to add to the queue
+ * @param nres the number of units of the resources of queue needed by the
+ *          operation. Should be greater than 0.
  */
 void
-GNUNET_TESTBED_operation_queue_remove_ (struct OperationQueue *queue,
-					struct GNUNET_TESTBED_Operation *operation)
+GNUNET_TESTBED_operation_queue_insert2_ (struct OperationQueue *queue,
+                                         struct GNUNET_TESTBED_Operation *op,
+                                         unsigned int nres)
 {
-  struct QueueEntry *entry;
-  struct QueueEntry *entry2;
-  
-  for (entry = queue->head; NULL != entry; entry = entry->next)
-    if (entry->op == operation)
-      break;
-  GNUNET_assert (NULL != entry);
-  if (OP_STATE_STARTED == operation->state)
-    queue->active++;
-  entry2 = entry->next;
-  GNUNET_CONTAINER_DLL_remove (queue->head, queue->tail, entry);
-  GNUNET_free (entry);
-  for (; NULL != entry2; entry2 = entry2->next)
-    if (OP_STATE_STARTED != entry2->op->state)
-      break;
-  if (NULL == entry2)
-    return;
-  check_readiness (entry2->op);
+  unsigned int qsize;
+
+  GNUNET_assert (0 < nres);
+  qsize = op->nqueues;
+  GNUNET_array_append (op->queues, op->nqueues, queue);
+  GNUNET_array_append (op->nres, qsize, nres);
+  GNUNET_assert (qsize == op->nqueues);
+}
+
+
+/**
+ * Add an operation to a queue.  An operation can be in multiple queues at
+ * once. Once the operation is inserted into all the queues
+ * GNUNET_TESTBED_operation_begin_wait_() has to be called to actually start
+ * waiting for the operation to become active. The operation is assumed to take
+ * 1 queue resource. Use GNUNET_TESTBED_operation_queue_insert2_() if it
+ * requires more than 1
+ *
+ * @param queue queue to add the operation to
+ * @param op operation to add to the queue
+ */
+void
+GNUNET_TESTBED_operation_queue_insert_ (struct OperationQueue *queue,
+                                        struct GNUNET_TESTBED_Operation *op)
+{
+  return GNUNET_TESTBED_operation_queue_insert2_ (queue, op, 1);
+}
+
+
+/**
+ * Marks the given operation as waiting on the queues.  Once all queues permit
+ * the operation to become active, the operation will be activated.  The actual
+ * activation will occur in a separate task (thus allowing multiple queue
+ * insertions to be made without having the first one instantly trigger the
+ * operation if the first queue has sufficient resources).
+ *
+ * @param op the operation to marks as waiting
+ */
+void
+GNUNET_TESTBED_operation_begin_wait_ (struct GNUNET_TESTBED_Operation *op)
+{
+  GNUNET_assert (NULL == op->rq_entry);
+  change_state (op, OP_STATE_WAITING);
+  (void) check_readiness (op);
+}
+
+
+/**
+ * Marks an active operation as inactive - the operation will be kept in a
+ * ready-to-be-released state and continues to hold resources until another
+ * operation contents for them.
+ *
+ * @param op the operation to be marked as inactive.  The operation start
+ *          callback should have been called before for this operation to mark
+ *          it as inactive.
+ */
+void
+GNUNET_TESTBED_operation_inactivate_ (struct GNUNET_TESTBED_Operation *op)
+{
+  struct OperationQueue **queues;
+  size_t ms;
+  unsigned int nqueues;
+  unsigned int i;
+
+  GNUNET_assert (OP_STATE_ACTIVE == op->state);
+  change_state (op, OP_STATE_INACTIVE);
+  nqueues = op->nqueues;
+  ms = sizeof (struct OperationQueue *) * nqueues;
+  queues = GNUNET_malloc (ms);
+  /* Cloning is needed as the operation be released by waiting operations and
+     hence its nqueues memory ptr will be freed */
+  GNUNET_memcpy (queues, op->queues, ms);
+  for (i = 0; i < nqueues; i++)
+    recheck_waiting (queues[i]);
+  GNUNET_free (queues);
+}
+
+
+/**
+ * Marks and inactive operation as active.  This fuction should be called to
+ * ensure that the oprelease callback will not be called until it is either
+ * marked as inactive or released.
+ *
+ * @param op the operation to be marked as active
+ */
+void
+GNUNET_TESTBED_operation_activate_ (struct GNUNET_TESTBED_Operation *op)
+{
+
+  GNUNET_assert (OP_STATE_INACTIVE == op->state);
+  change_state (op, OP_STATE_ACTIVE);
 }
 
 
@@ -300,25 +1284,95 @@ GNUNET_TESTBED_operation_queue_remove_ (struct OperationQueue *queue,
  * An operation is 'done' (was cancelled or finished); remove
  * it from the queues and release associated resources.
  *
- * @param operation operation that finished
+ * @param op operation that finished
  */
 void
-GNUNET_TESTBED_operation_release_ (struct GNUNET_TESTBED_Operation *operation)
+GNUNET_TESTBED_operation_release_ (struct GNUNET_TESTBED_Operation *op)
 {
+  struct QueueEntry *entry;
+  struct OperationQueue *opq;
   unsigned int i;
-    
-  if (GNUNET_SCHEDULER_NO_TASK != operation->start_task_id)
+
+  if (OP_STATE_INIT == op->state)
   {
-    GNUNET_SCHEDULER_cancel (operation->start_task_id);
-    operation->start_task_id = GNUNET_SCHEDULER_NO_TASK;
+    GNUNET_free (op);
+    return;
   }
-  for (i = 0; i < operation->nqueues; i++)
-    GNUNET_TESTBED_operation_queue_remove_ (operation->queues[i], operation);
-  GNUNET_free (operation->queues);
-  if (NULL != operation->release)
-    operation->release (operation->cb_cls);
-  GNUNET_free (operation);
+  if (OP_STATE_READY == op->state)
+    rq_remove (op);
+  if (OP_STATE_INACTIVE == op->state) /* Activate the operation if inactive */
+    GNUNET_TESTBED_operation_activate_ (op);
+  if (OP_STATE_ACTIVE == op->state)
+    update_tslots (op);
+  GNUNET_assert (NULL != op->queues);
+  GNUNET_assert (NULL != op->qentries);
+  for (i = 0; i < op->nqueues; i++)
+  {
+    entry = op->qentries[i];
+    remove_queue_entry (op, i);
+    opq = op->queues[i];
+    switch (op->state)
+    {
+    case OP_STATE_INIT:
+    case OP_STATE_INACTIVE:
+      GNUNET_assert (0);
+      break;
+    case OP_STATE_WAITING:
+      break;
+    case OP_STATE_ACTIVE:
+    case OP_STATE_READY:
+      GNUNET_assert (0 != opq->active);
+      GNUNET_assert (opq->active >= entry->nres);
+      opq->active -= entry->nres;
+      recheck_waiting (opq);
+      break;
+    }
+    GNUNET_free (entry);
+  }
+  GNUNET_free_non_null (op->qentries);
+  GNUNET_free (op->queues);
+  GNUNET_free (op->nres);
+  if (NULL != op->release)
+    op->release (op->cb_cls);
+  GNUNET_free (op);
 }
 
 
+/**
+ * Marks an operation as failed
+ *
+ * @param op the operation to be marked as failed
+ */
+void
+GNUNET_TESTBED_operation_mark_failed (struct GNUNET_TESTBED_Operation *op)
+{
+  op->failed = GNUNET_YES;
+}
+
+
+/**
+ * Cleanup expired operation queues.  While doing so, also check for any
+ * operations which are not completed and warn about them.
+ */
+void __attribute__ ((destructor))
+GNUNET_TESTBED_operations_fini ()
+{
+  struct OperationQueue *queue;
+  unsigned int i;
+  int warn = 0;
+
+  for (i=0; i < n_expired_opqs; i++)
+  {
+    queue = expired_opqs[i];
+    if (GNUNET_NO == is_queue_empty (queue))
+      warn = 1;
+    queue_destroy (queue);
+  }
+  GNUNET_free_non_null (expired_opqs);
+  n_expired_opqs = 0;
+  if (warn)
+    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+                "Be disciplined.  Some operations were not marked as done.\n");
+
+}
 /* end of testbed_api_operations.c */