X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fthread.cpp;h=8269dcf3d50029d2e4e355a8da8c345b48ddee80;hp=1f01537ffd2845ca311b509300eddedb5c9f899e;hb=d156e7a20b4ea15c2cbb4bcfa2dca5f1e96ece3b;hpb=e5ffe9959c40a5ec6c4bca83a5a48070cae7fa5b diff --git a/src/thread.cpp b/src/thread.cpp index 1f01537f..8269dcf3 100644 --- a/src/thread.cpp +++ b/src/thread.cpp @@ -27,23 +27,23 @@ ThreadsManager Threads; // Global object definition namespace { extern "C" { // start_routine() is the C function which is called when a new thread - // is launched. It simply calls idle_loop() of the supplied threadID. + // is launched. It simply calls idle_loop() of the supplied thread. // There are two versions of this function; one for POSIX threads and // one for Windows threads. #if defined(_MSC_VER) - DWORD WINAPI start_routine(LPVOID threadID) { + DWORD WINAPI start_routine(LPVOID thread) { - Threads[*(int*)threadID].idle_loop(NULL); + ((Thread*)thread)->idle_loop(NULL); return 0; } #else - void* start_routine(void* threadID) { + void* start_routine(void* thread) { - Threads[*(int*)threadID].idle_loop(NULL); + ((Thread*)thread)->idle_loop(NULL); return NULL; } @@ -63,9 +63,8 @@ void Thread::wake_up() { } -// 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. +// cutoff_occurred() checks whether a beta cutoff has occurred in the current +// active split point, or in some ancestor of the split point. bool Thread::cutoff_occurred() const { @@ -85,7 +84,7 @@ bool Thread::cutoff_occurred() const { bool Thread::is_available_to(int master) const { - if (state != AVAILABLE) + if (is_searching) return false; // Make a local copy to be sure doesn't become zero under our feet while @@ -148,11 +147,6 @@ void ThreadsManager::set_size(int cnt) { void ThreadsManager::init() { - // Threads will go to sleep as soon as created, only main thread is kept alive - set_size(1); - threads[0].state = Thread::SEARCHING; - threads[0].threadID = 0; - // Initialize threads lock, used when allocating slaves during splitting lock_init(&threadsLock); @@ -166,22 +160,28 @@ void ThreadsManager::init() { lock_init(&(threads[i].splitPoints[j].lock)); } - // Create and startup all the threads but the main that is already running + // Initialize main thread's associated data + threads[0].is_searching = true; + threads[0].threadID = 0; + set_size(1); // This makes all the threads but the main to go to sleep + + // Create and launch all the threads but the main that is already running, + // threads will go immediately to sleep. for (int i = 1; i < MAX_THREADS; i++) { - threads[i].state = Thread::AVAILABLE; + threads[i].is_searching = false; threads[i].threadID = i; #if defined(_MSC_VER) - threads[i].handle = CreateThread(NULL, 0, start_routine, (LPVOID)&threads[i].threadID, 0, NULL); + threads[i].handle = CreateThread(NULL, 0, start_routine, (LPVOID)&threads[i], 0, NULL); bool ok = (threads[i].handle != NULL); #else - bool ok = (pthread_create(&threads[i].handle, NULL, start_routine, (void*)&threads[i].threadID) == 0); + bool ok = (pthread_create(&threads[i].handle, NULL, start_routine, (void*)&threads[i]) == 0); #endif if (!ok) { - std::cout << "Failed to create thread number " << i << std::endl; + std::cerr << "Failed to create thread number " << i << std::endl; ::exit(EXIT_FAILURE); } } @@ -205,7 +205,6 @@ void ThreadsManager::exit() { CloseHandle(threads[i].handle); #else pthread_join(threads[i].handle, NULL); - pthread_detach(threads[i].handle); #endif } @@ -287,7 +286,7 @@ Value ThreadsManager::split(Position& pos, SearchStack* ss, Value alpha, Value b sp->is_slave[i] = false; // If we are here it means we are not available - assert(masterThread.state == Thread::SEARCHING); + assert(masterThread.is_searching); int workersCnt = 1; // At least the master is included @@ -304,7 +303,7 @@ Value ThreadsManager::split(Position& pos, SearchStack* ss, Value alpha, Value b threads[i].splitPoint = sp; // This makes the slave to exit from idle_loop() - threads[i].state = Thread::WORKISWAITING; + threads[i].is_searching = true; if (useSleepingThreads) threads[i].wake_up(); @@ -318,25 +317,24 @@ Value ThreadsManager::split(Position& pos, SearchStack* ss, Value alpha, Value b masterThread.splitPoint = sp; masterThread.activeSplitPoints++; - 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 - // loop when all threads have finished their work at this split point. + // 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, and // because here is all finished is not possible master is booked. - assert(masterThread.state == Thread::AVAILABLE); + assert(!masterThread.is_searching); // 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); - masterThread.state = Thread::SEARCHING; + masterThread.is_searching = true; masterThread.activeSplitPoints--; lock_release(&threadsLock);