#include "thread.h"
#include "ucioption.h"
-ThreadsManager ThreadsMgr; // Global object definition
+ThreadsManager Threads; // Global object definition
namespace {
void* init_thread(void* threadID) {
- ThreadsMgr.idle_loop(*(int*)threadID, NULL);
+ Threads.idle_loop(*(int*)threadID, NULL);
return NULL;
}
DWORD WINAPI init_thread(LPVOID threadID) {
- ThreadsMgr.idle_loop(*(int*)threadID, NULL);
+ Threads.idle_loop(*(int*)threadID, NULL);
return 0;
}
}
+// wake_up() wakes up the thread, normally at the beginning of the search or,
+// if "sleeping threads" is used, when there is some work to do.
+
+void Thread::wake_up() {
+
+ lock_grab(&sleepLock);
+ cond_signal(&sleepCond);
+ lock_release(&sleepLock);
+}
+
+
+// cutoff_occurred() checks whether a beta cutoff has occurred in
+// the thread's currently active split point, or in some ancestor of
+// the current split point.
+
+bool Thread::cutoff_occurred() const {
+
+ for (SplitPoint* sp = splitPoint; sp; sp = sp->parent)
+ if (sp->is_betaCutoff)
+ return true;
+ return false;
+}
+
+
+// is_available_to() checks whether the thread is available to help the thread with
+// threadID "master" at a split point. An obvious requirement is that thread must be
+// idle. With more than two threads, this is not by itself sufficient: If the thread
+// is the master of some active split point, it is only available as a slave to the
+// threads which are busy searching the split point at the top of "slave"'s split
+// point stack (the "helpful master concept" in YBWC terminology).
+
+bool Thread::is_available_to(int master) const {
+
+ if (state != AVAILABLE)
+ return false;
+
+ // 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;
+
+ // 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;
+}
+
+
// read_uci_options() updates number of active threads and other internal
// parameters according to the UCI options values. It is called before
// to start a new search.
activeThreads = Options["Threads"].value<int>();
}
+
// init_threads() is called during startup. Initializes locks and condition
// variables and launches all threads sending them immediately to sleep.
-void ThreadsManager::init_threads() {
+void ThreadsManager::init() {
- int i, arg[MAX_THREADS];
- bool ok;
+ int arg[MAX_THREADS];
// This flag is needed to properly end the threads when program exits
allThreadsShouldExit = false;
// Threads will sent to sleep as soon as created, only main thread is kept alive
activeThreads = 1;
+ threads[0].state = Thread::SEARCHING;
+
+ // Allocate pawn and material hash tables for main thread
+ init_hash_tables();
lock_init(&mpLock);
- for (i = 0; i < MAX_THREADS; i++)
+ // Initialize thread and split point locks
+ for (int i = 0; i < MAX_THREADS; i++)
{
- // Initialize thread and split point locks
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));
-
- // All threads but first should be set to THREAD_INITIALIZING
- threads[i].state = (i == 0 ? THREAD_SEARCHING : THREAD_INITIALIZING);
-
- // Not in Threads c'tor to avoid global initialization order issues
- threads[i].pawnTable.init();
- threads[i].materialTable.init();
}
- // Create and startup the threads
- for (i = 1; i < MAX_THREADS; i++)
+ // Create and startup all the threads but the main that is already running
+ for (int i = 1; i < MAX_THREADS; i++)
{
+ threads[i].state = Thread::INITIALIZING;
arg[i] = i;
#if !defined(_MSC_VER)
pthread_t pthread[1];
- ok = (pthread_create(pthread, NULL, init_thread, (void*)(&arg[i])) == 0);
+ bool ok = (pthread_create(pthread, NULL, init_thread, (void*)(&arg[i])) == 0);
pthread_detach(pthread[0]);
#else
- ok = (CreateThread(NULL, 0, init_thread, (LPVOID)(&arg[i]), 0, NULL) != NULL);
+ bool ok = (CreateThread(NULL, 0, init_thread, (LPVOID)(&arg[i]), 0, NULL) != NULL);
#endif
if (!ok)
{
std::cout << "Failed to create thread number " << i << std::endl;
- exit(EXIT_FAILURE);
+ ::exit(EXIT_FAILURE);
}
// Wait until the thread has finished launching and is gone to sleep
- while (threads[i].state == THREAD_INITIALIZING) {}
+ while (threads[i].state == Thread::INITIALIZING) {}
}
}
// exit_threads() is called when the program exits. It makes all the
// helper threads exit cleanly.
-void ThreadsManager::exit_threads() {
+void ThreadsManager::exit() {
// Force the woken up threads to exit idle_loop() and hence terminate
allThreadsShouldExit = true;
if (i != 0)
{
threads[i].wake_up();
- while (threads[i].state != THREAD_TERMINATED) {}
+ while (threads[i].state != Thread::TERMINATED) {}
}
// Now we can safely destroy the locks and wait conditions
}
-// cutoff_at_splitpoint() checks whether a beta cutoff has occurred in
-// the thread's currently active split point, or in some ancestor of
-// the current split point.
-
-bool ThreadsManager::cutoff_at_splitpoint(int threadID) const {
-
- assert(threadID >= 0 && threadID < activeThreads);
-
- SplitPoint* sp = threads[threadID].splitPoint;
+// init_hash_tables() dynamically allocates pawn and material hash tables
+// according to the number of active threads. This avoids preallocating
+// memory for all possible threads if only few are used as, for instance,
+// on mobile devices where memory is scarce and allocating for MAX_THREADS
+// threads could even result in a crash.
- for ( ; sp && !sp->betaCutoff; sp = sp->parent) {}
- return sp != NULL;
-}
-
-
-// thread_is_available() checks whether the thread with threadID "slave" is
-// available to help the thread with threadID "master" at a split point. An
-// obvious requirement is that "slave" must be idle. With more than two
-// threads, this is not by itself sufficient: If "slave" is the master of
-// some active split point, it is only available as a slave to the other
-// threads which are busy searching the split point at the top of "slave"'s
-// split point stack (the "helpful master concept" in YBWC terminology).
-
-bool ThreadsManager::thread_is_available(int slave, int master) const {
-
- assert(slave >= 0 && slave < activeThreads);
- assert(master >= 0 && master < activeThreads);
- assert(activeThreads > 1);
+void ThreadsManager::init_hash_tables() {
- if (threads[slave].state != THREAD_AVAILABLE || slave == master)
- return false;
-
- // Make a local copy to be sure doesn't change under our feet
- int localActiveSplitPoints = threads[slave].activeSplitPoints;
-
- // No active split points means that the thread is available as
- // a slave for any other thread.
- if (localActiveSplitPoints == 0 || activeThreads == 2)
- return true;
-
- // Apply the "helpful master" concept if possible. Use localActiveSplitPoints
- // that is known to be > 0, instead of threads[slave].activeSplitPoints that
- // could have been set to 0 by another thread leading to an out of bound access.
- if (threads[slave].splitPoints[localActiveSplitPoints - 1].slaves[master])
- return true;
-
- return false;
+ for (int i = 0; i < activeThreads; i++)
+ {
+ threads[i].pawnTable.init();
+ threads[i].materialTable.init();
+ }
}
-// available_thread_exists() tries to find an idle thread which is available as
+// available_slave_exists() tries to find an idle thread which is available as
// a slave for the thread with threadID "master".
-bool ThreadsManager::available_thread_exists(int master) const {
+bool ThreadsManager::available_slave_exists(int master) const {
assert(master >= 0 && master < activeThreads);
- assert(activeThreads > 1);
for (int i = 0; i < activeThreads; i++)
- if (thread_is_available(i, master))
+ if (i != master && threads[i].is_available_to(master))
return true;
return false;
// If no other thread is available to help us, or if we have too many
// active split points, don't split.
- if ( !available_thread_exists(master)
+ if ( !available_slave_exists(master)
|| masterThread.activeSplitPoints >= MAX_ACTIVE_SPLIT_POINTS)
{
lock_release(&mpLock);
// Initialize the split point object
splitPoint.parent = masterThread.splitPoint;
splitPoint.master = master;
- splitPoint.betaCutoff = false;
+ splitPoint.is_betaCutoff = false;
splitPoint.depth = depth;
splitPoint.threatMove = threatMove;
splitPoint.alpha = *alpha;
splitPoint.nodes = 0;
splitPoint.ss = ss;
for (i = 0; i < activeThreads; i++)
- splitPoint.slaves[i] = 0;
+ splitPoint.is_slave[i] = false;
masterThread.splitPoint = &splitPoint;
// If we are here it means we are not available
- assert(masterThread.state != THREAD_AVAILABLE);
+ assert(masterThread.state != Thread::AVAILABLE);
int workersCnt = 1; // At least the master is included
// Allocate available threads setting state to THREAD_BOOKED
for (i = 0; !Fake && i < activeThreads && workersCnt < maxThreadsPerSplitPoint; i++)
- if (thread_is_available(i, master))
+ if (i != master && threads[i].is_available_to(master))
{
- threads[i].state = THREAD_BOOKED;
+ threads[i].state = Thread::BOOKED;
threads[i].splitPoint = &splitPoint;
- splitPoint.slaves[i] = 1;
+ splitPoint.is_slave[i] = true;
workersCnt++;
}
// Tell the threads that they have work to do. This will make them leave
// their idle loop.
for (i = 0; i < activeThreads; i++)
- if (i == master || splitPoint.slaves[i])
+ if (i == master || splitPoint.is_slave[i])
{
- assert(i == master || threads[i].state == THREAD_BOOKED);
+ assert(i == master || threads[i].state == Thread::BOOKED);
- threads[i].state = THREAD_WORKISWAITING; // This makes the slave to exit from idle_loop()
+ threads[i].state = Thread::WORKISWAITING; // This makes the slave to exit from idle_loop()
if (useSleepingThreads && i != master)
threads[i].wake_up();
}
// Explicit template instantiations
-template void ThreadsManager::split<0>(Position&, SearchStack*, Value*, const Value, Value*, Depth, Move, int, MovePicker*, bool);
-template void ThreadsManager::split<1>(Position&, SearchStack*, Value*, const Value, Value*, Depth, Move, int, MovePicker*, bool);
+template void ThreadsManager::split<false>(Position&, SearchStack*, Value*, const Value, Value*, Depth, Move, int, MovePicker*, bool);
+template void ThreadsManager::split<true>(Position&, SearchStack*, Value*, const Value, Value*, Depth, Move, int, MovePicker*, bool);
projects / stockfish / blobdiff