c4snet_data_t *C4SNetShallowCopy(c4snet_data_t *data)
{
#if HAVE_SYNC_ATOMIC_BUILTINS
/* Temporary fix for race condition: */
AAF(&data->ref_count, 1);
#else
/* Old code, which contains a race condition: */
data->ref_count++;
#endif
return data;
}
/* Scan other workers for stealable items */
static bool SNetWorkerSteal(worker_t *thief)
{
int i;
assert(thief->loot.desc == NULL);
assert(thief->loot.item == NULL);
for (i = 0; i < snet_worker_count && !thief->loot.desc; ++i) {
thief->victim_id = 1 + (thief->victim_id % snet_worker_count);
if (thief->victim_id != thief->id) {
worker_t *victim = snet_workers[thief->victim_id];
if (victim && trylock_worker(victim, thief)) {
AAF(&victim->steal_turn->turn, 1);
SNetWorkerStealVictim(victim, thief);
AAF(&victim->steal_turn->turn, 1);
unlock_worker(victim, thief);
}
}
}
return (thief->loot.desc != NULL);
}
/* Merge a stream to an identity landing with the subsequent stream. */
static snet_stream_desc_t *SNetMergeStreams(snet_stream_desc_t **desc_ptr)
{
snet_stream_desc_t *desc = *desc_ptr;
snet_stream_desc_t *next = DESC_LAND_SPEC(desc, identity)->outdesc;
fifo_node_t *fifo_tail_start;
fifo_node_t *fifo_tail_end;
fifo_node_t *node;
int count = 0;
/* Remove all data from the queue towards the garbage landing. */
fifo_tail_start = SNetFifoGetTail(&desc->fifo, &fifo_tail_end);
/* Count the number of data items in the captured list. */
for (node = fifo_tail_start; node; node = node->next) {
++count;
}
/* Append the captured list onto the subsequent stream. */
SNetFifoPutTail(&next->fifo, fifo_tail_start, fifo_tail_end);
/* Reconnect the source landing of the next landing. */
next->source = desc->source;
/* Increase the reference count by the number of added records. */
AAF(&(next->refs), count);
/* Report statistics. */
if (SNetDebug()) {
printf("%s: collecting %d recs, %d drefs, %d nrefs\n",
__func__, count, desc->refs, next->refs);
}
/* Convert the identity landing into garbage. */
SNetBecomeGarbage(desc->landing);
/* Make sure no one ever attempts to write to the dissolved stream. */
*desc_ptr = next;
/* Unlock the garbage landing: some worker todo items may still need it. */
unlock_landing(desc->landing);
/* Decrease reference count to the garbage collected stream. */
SNetDescDone(desc);
/* Return the subsequent stream. */
return next;
}
/* Process a stolen item. */
static void SNetWorkerLoot(worker_t *worker)
{
if (worker->loot.desc) {
if (worker->loot.item) {
if (worker->loot.count > 0) {
AAF(&(worker->loot.item->count), worker->loot.count);
}
if (trylock_work_item(worker->loot.item, worker)) {
if (worker->loot.item->count > 0) {
SNetWorkerWorkItem(worker->loot.item, worker);
}
if (worker->loot.item->lock == worker->id) {
unlock_work_item(worker->loot.item, worker);
}
}
}
else /* (worker->loot.item == NULL) */ {
work_item_t *item = GetFreeWorkItem(worker);
item->next_item = NULL;
item->next_free = NULL;
item->desc = worker->loot.desc;
item->lock = worker->id;
item->count = worker->loot.count;
SNetHashPtrStore(worker->hash_ptab, item->desc, item);
SNetWorkerWorkItem(item, worker);
if (item->count == 0) {
if (item->desc) {
SNetHashPtrRemove(worker->hash_ptab, item->desc);
}
item->lock = worker->id;
PutFreeWorkItem(worker, item);
} else {
item->lock = 0;
item->next_item = worker->prev->next_item;
BAR();
worker->prev->next_item = worker->iter = item;
}
}
worker->loot.desc = NULL;
worker->loot.count = 0;
worker->loot.item = NULL;
worker->has_work = (worker->todo.head.next_item != NULL);
}
}
/* Add a new unit of work to the worker's todo list.
* At return iterator should point to the new item.
*/
void SNetWorkerTodo(worker_t *worker, snet_stream_desc_t *desc)
{
work_item_t *item = SNetHashPtrLookup(worker->hash_ptab, desc);
if (item) {
/* Item may be locked by a thief. */
AAF(&item->count, 1);
} else {
item = GetFreeWorkItem(worker);
item->count = 1;
item->desc = desc;
item->lock = 0;
item->next_free = NULL;
item->next_item = worker->prev->next_item;
BAR();
worker->prev->next_item = item;
worker->prev = item;
SNetHashPtrStore(worker->hash_ptab, desc, item);
worker->has_work = true;
}
}
AAF sin(const AAF & P)
{
if(P.is_infinite())
return AAF(interval(-1,1));
interval i = P.convert();
double w = i.width();
const double a = i.left();
const double b = i.right();
// y' = alpha*x+dzeta , the regression line
// approximate y = sin(x)
double alpha, dzeta, delta;
if (w >= 2*PI ) {
// the trivial case, the interval is larger than 2*PI
// y' = 0 , delta = 1 cause -1 <= sin(x) <= +1
return AAF(interval(-1,1));
alpha = 0.0;
dzeta = 0.0;
delta = 1.0;
} else {
// case of the least squares
double x[NPTS];
double y[NPTS];
double r[NPTS]; // residues, r[i] = y[i]-y'[i]
x[0] = a;
y[0] = sin(a);
x[NPTS-1] = b;
y[NPTS-1] = sin(b);
double pas = w/(NPTS-1);
for (unsigned i=1; i< NPTS-1; i++) {
x[i] = x[i-1]+pas;
y[i] = sin(x[i]);
}
// Calculation of xm and ym , averages of x and y
double xm = 0;
double ym = 0;
for (unsigned i=0; i<NPTS; i++) {
xm = xm + x[i];
ym = ym + y[i];
}
xm = xm/NPTS;
ym = ym/NPTS;
// Calculation of alpha and dzeta
double temp2 = 0;
alpha = 0;
for (unsigned i = 0; i < NPTS; i++) {
const double temp1 = x[i] - xm;
alpha += y[i]*temp1;
temp2 += temp1*temp1;
}
alpha = alpha/temp2; // final alpha
dzeta = ym - alpha*xm; // final dzeta
// Calculation of the residues
// We use the absolute value of the residues!
for (unsigned i = 0; i < NPTS; i++) {
r[i] = fabs(y[i] - (dzeta+alpha*x[i]));
}
// The error delta is the maximum
// of the residues (in absolute values)
delta = *std::max_element(r, r+NPTS);
}
return AAF(P, alpha, dzeta, delta, P.special);
}
/* Work on an item.
*
* In case of a dissolved garbage stream update the source
* stream of the work item.
*
* Return true iff a record was processed.
*
* If the contents of the item was merged with another item then
* reset the item descriptor to NULL.
*/
static bool SNetWorkerWorkItem(work_item_t *const item, worker_t *worker)
{
work_item_t *lookup;
/* Item must be owned and non-empty. */
assert(item->lock == worker->id);
assert(item->count > 0);
/* Claim destination landing. */
if (trylock_landing(item->desc->landing, worker) == false) {
/* Nothing can be done. */
return false;
}
/* Bring item descriptors past any garbage collectable landings. */
while (item->desc->landing->type == LAND_garbage) {
/* Get subsequent descriptor. */
snet_stream_desc_t *next_desc = DESC_LAND_SPEC(item->desc, siso)->outdesc;
/* Release landing claim. */
unlock_landing(item->desc->landing);
/* Decrease reference counts to descriptor. */
SNetDescRelease(item->desc, item->count);
/* Take item out of hash table. */
SNetHashPtrRemove(worker->hash_ptab, item->desc);
/* Update item descriptor. */
item->desc = next_desc;
/* Also advance past subsequent garbage landings. */
while (next_desc->landing->type == LAND_garbage) {
/* Get subsequent descriptor. */
item->desc = DESC_LAND_SPEC(next_desc, siso)->outdesc;
/* Test if current descriptor is also in our hash table. */
lookup = (work_item_t *)SNetHashPtrLookup(worker->hash_ptab, next_desc);
if (lookup && trylock_work_item(lookup, worker)) {
/* Merge both descriptor counts into one. */
item->count += lookup->count;
lookup->count = 0;
unlock_work_item(lookup, worker);
}
/* Decrease reference counts to garbage descriptor. */
SNetDescRelease(next_desc, item->count);
/* Advance to subsequent descriptor and repeat. */
next_desc = item->desc;
}
/* The new descriptor may already exist in hash table. */
lookup = (work_item_t *)SNetHashPtrLookup(worker->hash_ptab, next_desc);
if (lookup) {
/* Merge the two counts. */
AAF(&lookup->count, item->count);
/* Reset item. */
item->count = 0;
/* We already have this desciptor in lookup, so reset it. */
item->desc = NULL;
/* We made progress. */
return true;
}
else /* (lookup == NULL) */ {
/* Add new descriptor to hash table. */
SNetHashPtrStore(worker->hash_ptab, item->desc, item);
/* Claim destination landing. */
if (trylock_landing(item->desc->landing, worker) == false) {
/* We made progress anyway. */
return true;
}
}
}
/* Subtract one read license. */
--item->count;
/* Unlock item so thieves can steal it while we work. */
unlock_work_item(item, worker);
/* Finally, do the work by delegating to the streams layer. */
SNetStreamWork(item->desc, worker);
/* We definitely made progress. */
return true;
}
