along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
+#include <cassert>
#include <iostream>
#include "movegen.h"
// and last thread are special. First one is the main search thread while the
// last one mimics a timer, they run in main_loop() and timer_loop().
-#if defined(_MSC_VER)
+#if defined(_WIN32) || defined(_WIN64)
DWORD WINAPI start_routine(LPVOID thread) {
#else
void* start_routine(void* thread) {
void Thread::wake_up() {
- lock_grab(&sleepLock);
- cond_signal(&sleepCond);
- lock_release(&sleepLock);
+ lock_grab(sleepLock);
+ cond_signal(sleepCond);
+ lock_release(sleepLock);
}
// Make a local copy to be sure doesn't become zero under our feet while
// testing next condition and so leading to an out of bound access.
- int localActiveSplitPoints = activeSplitPoints;
+ int sp_count = activeSplitPoints;
// No active split points means that the thread is available as a slave for any
// other thread otherwise apply the "helpful master" concept if possible.
- if ( !localActiveSplitPoints
- || splitPoints[localActiveSplitPoints - 1].is_slave[master])
- return true;
-
- return false;
+ return !sp_count || (splitPoints[sp_count - 1].slavesMask & (1ULL << master));
}
void ThreadsManager::init() {
- // Initialize sleep condition and lock used by thread manager
- cond_init(&sleepCond);
- lock_init(&threadsLock);
+ cond_init(sleepCond);
+ lock_init(splitLock);
- // Initialize thread's sleep conditions and split point locks
for (int i = 0; i <= MAX_THREADS; i++)
{
- lock_init(&threads[i].sleepLock);
- cond_init(&threads[i].sleepCond);
+ lock_init(threads[i].sleepLock);
+ cond_init(threads[i].sleepCond);
for (int j = 0; j < MAX_ACTIVE_SPLIT_POINTS; j++)
- lock_init(&(threads[i].splitPoints[j].lock));
+ lock_init(threads[i].splitPoints[j].lock);
}
// Allocate main thread tables to call evaluate() also when not searching
threads[i].do_sleep = (i != 0); // Avoid a race with start_thinking()
threads[i].threadID = i;
-#if defined(_MSC_VER)
- threads[i].handle = CreateThread(NULL, 0, start_routine, &threads[i], 0, NULL);
- bool ok = (threads[i].handle != NULL);
-#else
- bool ok = !pthread_create(&threads[i].handle, NULL, start_routine, &threads[i]);
-#endif
-
- if (!ok)
+ if (!thread_create(threads[i].handle, start_routine, threads[i]))
{
std::cerr << "Failed to create thread number " << i << std::endl;
::exit(EXIT_FAILURE);
void ThreadsManager::exit() {
+ assert(threads[0].is_searching == false);
+
for (int i = 0; i <= MAX_THREADS; i++)
{
- threads[i].do_terminate = true; // Search must be already finished
+ threads[i].do_exit = true; // Search must be already finished
threads[i].wake_up();
- // Wait for thread termination
-#if defined(_MSC_VER)
- WaitForSingleObject(threads[i].handle, INFINITE);
- CloseHandle(threads[i].handle);
-#else
- pthread_join(threads[i].handle, NULL);
-#endif
+ thread_join(threads[i].handle); // Wait for thread termination
- // Now we can safely destroy associated locks and wait conditions
- lock_destroy(&threads[i].sleepLock);
- cond_destroy(&threads[i].sleepCond);
+ lock_destroy(threads[i].sleepLock);
+ cond_destroy(threads[i].sleepCond);
for (int j = 0; j < MAX_ACTIVE_SPLIT_POINTS; j++)
- lock_destroy(&(threads[i].splitPoints[j].lock));
+ lock_destroy(threads[i].splitPoints[j].lock);
}
- lock_destroy(&threadsLock);
- cond_destroy(&sleepCond);
+ lock_destroy(splitLock);
+ cond_destroy(sleepCond);
}
}
-// split_point_finished() checks if all the slave threads of a given split
-// point have finished searching.
-
-bool ThreadsManager::split_point_finished(SplitPoint* sp) const {
-
- for (int i = 0; i < activeThreads; i++)
- if (sp->is_slave[i])
- return false;
-
- return true;
-}
-
-
// split() does the actual work of distributing the work at a node between
// several available threads. If it does not succeed in splitting the node
// (because no idle threads are available, or because we have no unused split
assert(pos.thread() >= 0 && pos.thread() < activeThreads);
assert(activeThreads > 1);
- int i, master = pos.thread();
+ int master = pos.thread();
Thread& masterThread = threads[master];
- // If we already have too many active split points, don't split
if (masterThread.activeSplitPoints >= MAX_ACTIVE_SPLIT_POINTS)
return bestValue;
// Pick the next available split point from the split point stack
SplitPoint* sp = &masterThread.splitPoints[masterThread.activeSplitPoints];
- // Initialize the split point
sp->parent = masterThread.splitPoint;
sp->master = master;
sp->is_betaCutoff = false;
+ sp->slavesMask = 1ULL << master;
sp->depth = depth;
sp->threatMove = threatMove;
sp->alpha = alpha;
sp->nodes = 0;
sp->ss = ss;
- for (i = 0; i < activeThreads; i++)
- sp->is_slave[i] = false;
-
- // If we are here it means we are not available
assert(masterThread.is_searching);
- int workersCnt = 1; // At least the master is included
+ int slavesCnt = 0;
// Try to allocate available threads and ask them to start searching setting
// is_searching flag. This must be done under lock protection to avoid concurrent
// allocation of the same slave by another master.
- lock_grab(&threadsLock);
+ lock_grab(sp->lock);
+ lock_grab(splitLock);
- for (i = 0; !Fake && i < activeThreads && workersCnt < maxThreadsPerSplitPoint; i++)
+ for (int i = 0; i < activeThreads && !Fake; i++)
if (threads[i].is_available_to(master))
{
- workersCnt++;
- sp->is_slave[i] = true;
+ sp->slavesMask |= 1ULL << i;
threads[i].splitPoint = sp;
-
- // This makes the slave to exit from idle_loop()
- threads[i].is_searching = true;
+ threads[i].is_searching = true; // Slave leaves idle_loop()
if (useSleepingThreads)
threads[i].wake_up();
- }
-
- lock_release(&threadsLock);
- // We failed to allocate even one slave, return
- if (!Fake && workersCnt == 1)
- return bestValue;
+ if (++slavesCnt + 1 >= maxThreadsPerSplitPoint) // Master is always included
+ break;
+ }
masterThread.splitPoint = sp;
masterThread.activeSplitPoints++;
+ lock_release(splitLock);
+ lock_release(sp->lock);
+
// Everything is set up. The master thread enters the idle loop, from which
// it will instantly launch a search, because its is_searching flag is set.
// We pass the split point as a parameter to the idle loop, which means that
// the thread will return from the idle loop when all slaves have finished
// their work at this split point.
- masterThread.idle_loop(sp);
-
- // In helpful master concept a master can help only a sub-tree of its split
- // point, and because here is all finished is not possible master is booked.
- assert(!masterThread.is_searching);
+ if (slavesCnt || Fake)
+ masterThread.idle_loop(sp);
// We have returned from the idle loop, which means that all threads are
- // finished. Note that changing state and decreasing activeSplitPoints is done
- // under lock protection to avoid a race with Thread::is_available_to().
- lock_grab(&threadsLock);
+ // finished. Note that setting is_searching and decreasing activeSplitPoints is
+ // done under lock protection to avoid a race with Thread::is_available_to().
+ lock_grab(sp->lock); // To protect sp->nodes
+ lock_grab(splitLock);
masterThread.is_searching = true;
masterThread.activeSplitPoints--;
-
- lock_release(&threadsLock);
-
masterThread.splitPoint = sp->parent;
pos.set_nodes_searched(pos.nodes_searched() + sp->nodes);
+ lock_release(splitLock);
+ lock_release(sp->lock);
+
return sp->bestValue;
}
void Thread::timer_loop() {
- while (!do_terminate)
+ while (!do_exit)
{
- lock_grab(&sleepLock);
- timed_wait(&sleepCond, &sleepLock, maxPly ? maxPly : INT_MAX);
- lock_release(&sleepLock);
+ lock_grab(sleepLock);
+ timed_wait(sleepCond, sleepLock, maxPly ? maxPly : INT_MAX);
+ lock_release(sleepLock);
check_time();
}
}
Thread& timer = threads[MAX_THREADS];
- lock_grab(&timer.sleepLock);
+ lock_grab(timer.sleepLock);
timer.maxPly = msec;
- cond_signal(&timer.sleepCond); // Wake up and restart the timer
- lock_release(&timer.sleepLock);
+ cond_signal(timer.sleepCond); // Wake up and restart the timer
+ lock_release(timer.sleepLock);
}
while (true)
{
- lock_grab(&sleepLock);
+ lock_grab(sleepLock);
do_sleep = true; // Always return to sleep after a search
is_searching = false;
- while (do_sleep && !do_terminate)
+ while (do_sleep && !do_exit)
{
- cond_signal(&Threads.sleepCond); // Wake up UI thread if needed
- cond_wait(&sleepCond, &sleepLock);
+ cond_signal(Threads.sleepCond); // Wake up UI thread if needed
+ cond_wait(sleepCond, sleepLock);
}
is_searching = true;
- lock_release(&sleepLock);
+ lock_release(sleepLock);
- if (do_terminate)
+ if (do_exit)
return;
Search::think();
const std::set<Move>& searchMoves, bool async) {
Thread& main = threads[0];
- lock_grab(&main.sleepLock);
+ lock_grab(main.sleepLock);
// Wait main thread has finished before to launch a new search
while (!main.do_sleep)
- cond_wait(&sleepCond, &main.sleepLock);
+ cond_wait(sleepCond, main.sleepLock);
// Copy input arguments to initialize the search
RootPosition.copy(pos, 0);
Signals.stop = Signals.failedLowAtRoot = false;
main.do_sleep = false;
- cond_signal(&main.sleepCond); // Wake up main thread and start searching
+ cond_signal(main.sleepCond); // Wake up main thread and start searching
if (!async)
while (!main.do_sleep)
- cond_wait(&sleepCond, &main.sleepLock);
+ cond_wait(sleepCond, main.sleepLock);
- lock_release(&main.sleepLock);
+ lock_release(main.sleepLock);
}
Search::Signals.stop = true;
- lock_grab(&main.sleepLock);
+ lock_grab(main.sleepLock);
- cond_signal(&main.sleepCond); // In case is waiting for stop or ponderhit
+ cond_signal(main.sleepCond); // In case is waiting for stop or ponderhit
while (!main.do_sleep)
- cond_wait(&sleepCond, &main.sleepLock);
+ cond_wait(sleepCond, main.sleepLock);
- lock_release(&main.sleepLock);
+ lock_release(main.sleepLock);
}
Thread& main = threads[0];
- lock_grab(&main.sleepLock);
+ lock_grab(main.sleepLock);
while (!Signals.stop)
- cond_wait(&main.sleepCond, &main.sleepLock);
+ cond_wait(main.sleepCond, main.sleepLock);
- lock_release(&main.sleepLock);
+ lock_release(main.sleepLock);
}