+/**
+ * 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 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++)
+ {
+ 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++)
+ {
+ 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);
+ }
+}
+
+
+/**
+ * Create an 'operation' to be performed.
+ *
+ * @param cls closure for the callbacks
+ * @param start function to call to start the operation
+ * @param release function to call to close down the operation
+ * @return handle to the operation
+ */
+struct GNUNET_TESTBED_Operation *
+GNUNET_TESTBED_operation_create_ (void *cls, OperationStart start,
+ OperationRelease release)
+{
+ struct GNUNET_TESTBED_Operation *op;
+
+ op = GNUNET_new (struct GNUNET_TESTBED_Operation);
+ op->start = start;
+ op->state = OP_STATE_INIT;
+ op->release = release;
+ op->cb_cls = cls;
+ return op;
+}