// Allocate pawn and material hash tables for main thread
init_hash_tables();
+ // Initialize threads lock, used when allocating slaves during splitting
lock_init(&threadsLock);
- // Initialize thread and split point locks
+ // Initialize sleep and split point locks
for (int i = 0; i < MAX_THREADS; i++)
{
lock_init(&threads[i].sleepLock);
}
-// exit() is called to cleanly exit the threads when the program finishes
+// exit() is called to cleanly terminate the threads when the program finishes
void ThreadsManager::exit() {
for (int i = 0; i < MAX_THREADS; i++)
{
- // Wake up all the threads and waits for termination
+ // Wake up all the threads and wait for termination
if (i != 0)
{
threads[i].wake_up();
while (threads[i].state != Thread::TERMINATED) {}
}
- // Now we can safely destroy the locks and wait conditions
+ // Now we can safely destroy locks and wait conditions
lock_destroy(&threads[i].sleepLock);
cond_destroy(&threads[i].sleepCond);
return bestValue;
// Pick the next available split point object from the split point stack
- SplitPoint& splitPoint = masterThread.splitPoints[masterThread.activeSplitPoints];
+ SplitPoint* sp = masterThread.splitPoints + masterThread.activeSplitPoints;
// Initialize the split point object
- splitPoint.parent = masterThread.splitPoint;
- splitPoint.master = master;
- splitPoint.is_betaCutoff = false;
- splitPoint.depth = depth;
- splitPoint.threatMove = threatMove;
- splitPoint.alpha = alpha;
- splitPoint.beta = beta;
- splitPoint.nodeType = nodeType;
- splitPoint.bestValue = bestValue;
- splitPoint.mp = mp;
- splitPoint.moveCount = moveCount;
- splitPoint.pos = &pos;
- splitPoint.nodes = 0;
- splitPoint.ss = ss;
+ sp->parent = masterThread.splitPoint;
+ sp->master = master;
+ sp->is_betaCutoff = false;
+ sp->depth = depth;
+ sp->threatMove = threatMove;
+ sp->alpha = alpha;
+ sp->beta = beta;
+ sp->nodeType = nodeType;
+ sp->bestValue = bestValue;
+ sp->mp = mp;
+ sp->moveCount = moveCount;
+ sp->pos = &pos;
+ sp->nodes = 0;
+ sp->ss = ss;
for (i = 0; i < activeThreads; i++)
- splitPoint.is_slave[i] = false;
+ sp->is_slave[i] = false;
// If we are here it means we are not available
assert(masterThread.state == Thread::SEARCHING);
- int booked = 0;
+ int workersCnt = 1; // At least the master is included
- // Try to allocate available threads setting state to Thread::BOOKED, this
- // must be done under lock protection to avoid concurrent allocation of
- // the same slave by another master.
+ // Try to allocate available threads and ask them to start searching setting
+ // the state to Thread::WORKISWAITING, this must be done under lock protection
+ // to avoid concurrent allocation of the same slave by another master.
lock_grab(&threadsLock);
- for (i = 0; !Fake && i < activeThreads && booked < maxThreadsPerSplitPoint; i++)
+ for (i = 0; !Fake && i < activeThreads && workersCnt < maxThreadsPerSplitPoint; i++)
if (i != master && threads[i].is_available_to(master))
{
- threads[i].state = Thread::BOOKED;
- threads[i].splitPoint = &splitPoint;
- splitPoint.is_slave[i] = true;
- booked++;
+ workersCnt++;
+ sp->is_slave[i] = true;
+ threads[i].splitPoint = sp;
+
+ // This makes the slave to exit from idle_loop()
+ threads[i].state = Thread::WORKISWAITING;
+
+ if (useSleepingThreads)
+ threads[i].wake_up();
}
lock_release(&threadsLock);
// We failed to allocate even one slave, return
- if (!Fake && !booked)
+ if (!Fake && workersCnt == 1)
return bestValue;
+ masterThread.splitPoint = sp;
masterThread.activeSplitPoints++;
- masterThread.splitPoint = &splitPoint;
-
- // Tell the threads that they have some work to do. This will make them leave
- // their idle loop.
- for (i = 0; i < activeThreads; i++)
- if (i == master || splitPoint.is_slave[i])
- {
- assert(i == master || threads[i].state == Thread::BOOKED);
-
- // This makes the slave to exit from idle_loop()
- threads[i].state = Thread::WORKISWAITING;
-
- if (useSleepingThreads && i != master)
- threads[i].wake_up();
- }
+ masterThread.state = Thread::WORKISWAITING;
// Everything is set up. The master thread enters the idle loop, from
// which it will instantly launch a search, because its state is
- // THREAD_WORKISWAITING. We send the split point as a second parameter to the
- // idle loop, which means that the main thread will return from the idle
+ // Thread::WORKISWAITING. We send the split point as a second parameter to
+ // the idle loop, which means that the main thread will return from the idle
// loop when all threads have finished their work at this split point.
- idle_loop(master, &splitPoint);
+ idle_loop(master, sp);
+
+ // In helpful master concept a master can help only a sub-tree, and
+ // because here is all finished is not possible master is booked.
+ assert(masterThread.state == Thread::AVAILABLE);
// We have returned from the idle loop, which means that all threads are
// finished. Note that changing state and decreasing activeSplitPoints is done
masterThread.state = Thread::SEARCHING;
masterThread.activeSplitPoints--;
- masterThread.splitPoint = splitPoint.parent;
lock_release(&threadsLock);
- pos.set_nodes_searched(pos.nodes_searched() + splitPoint.nodes);
- return splitPoint.bestValue;
+ masterThread.splitPoint = sp->parent;
+ pos.set_nodes_searched(pos.nodes_searched() + sp->nodes);
+
+ return sp->bestValue;
}
// Explicit template instantiations
projects / stockfish / blobdiff