#ifndef THREAD_H_INCLUDED
#define THREAD_H_INCLUDED
-#include <atomic>
#include <bitset>
-#include <condition_variable>
-#include <mutex>
-#include <thread>
#include <vector>
#include "material.h"
const size_t MAX_SPLITPOINTS_PER_THREAD = 8;
const size_t MAX_SLAVES_PER_SPLITPOINT = 4;
-#if 0
-/// Spinlock class wraps low level atomic operations to provide a spin lock
+/// Mutex and ConditionVariable struct are wrappers of the low level locking
+/// machinery and are modeled after the corresponding C++11 classes.
-class Spinlock {
+struct Mutex {
+ Mutex() { lock_init(l); }
+ ~Mutex() { lock_destroy(l); }
- std::atomic_int lock;
+ void lock() { lock_grab(l); }
+ void unlock() { lock_release(l); }
-public:
- Spinlock() { lock = 1; } // Init here to workaround a bug with MSVC 2013
- void acquire() {
- while (lock.fetch_sub(1, std::memory_order_acquire) != 1)
- while (lock.load(std::memory_order_relaxed) <= 0) {}
- }
- void release() { lock.store(1, std::memory_order_release); }
-};
+private:
+ friend struct ConditionVariable;
-#else
+ Lock l;
+};
-class Spinlock {
+struct ConditionVariable {
+ ConditionVariable() { cond_init(c); }
+ ~ConditionVariable() { cond_destroy(c); }
- std::mutex mutex;
+ void wait(Mutex& m) { cond_wait(c, m.l); }
+ void wait_for(Mutex& m, int ms) { timed_wait(c, m.l, ms); }
+ void notify_one() { cond_signal(c); }
-public:
- void acquire() { mutex.lock(); }
- void release() { mutex.unlock(); }
+private:
+ WaitCondition c;
};
-#endif
/// SplitPoint struct stores information shared by the threads searching in
/// parallel below the same split point. It is populated at splitting time.
SplitPoint* parentSplitPoint;
// Shared variable data
- Spinlock spinlock;
+ Mutex mutex;
std::bitset<MAX_THREADS> slavesMask;
volatile bool allSlavesSearching;
volatile uint64_t nodes;
struct ThreadBase {
- virtual ~ThreadBase() = default;
+ ThreadBase() : handle(NativeHandle()), exit(false) {}
+ virtual ~ThreadBase() {}
virtual void idle_loop() = 0;
void notify_one();
void wait_for(volatile const bool& b);
- std::thread nativeThread;
- std::mutex mutex;
- std::condition_variable sleepCondition;
- volatile bool exit = false;
+ Mutex mutex;
+ ConditionVariable sleepCondition;
+ NativeHandle handle;
+ volatile bool exit;
};
Thread();
virtual void idle_loop();
bool cutoff_occurred() const;
- bool can_join(const SplitPoint* sp) const;
+ bool available_to(const Thread* master) const;
void split(Position& pos, Search::Stack* ss, Value alpha, Value beta, Value* bestValue, Move* bestMove,
Depth depth, int moveCount, MovePicker* movePicker, int nodeType, bool cutNode);
/// special threads: the main one and the recurring timer.
struct MainThread : public Thread {
+ MainThread() : thinking(true) {} // Avoid a race with start_thinking()
virtual void idle_loop();
- volatile bool thinking = true; // Avoid a race with start_thinking()
+ volatile bool thinking;
};
struct TimerThread : public ThreadBase {
static const int Resolution = 5; // Millisec between two check_time() calls
+ TimerThread() : run(false) {}
virtual void idle_loop();
- bool run = false;
+ bool run;
};
MainThread* main() { return static_cast<MainThread*>(at(0)); }
void read_uci_options();
- Thread* available_slave(const SplitPoint* sp) const;
+ Thread* available_slave(const Thread* master) const;
void wait_for_think_finished();
void start_thinking(const Position&, const Search::LimitsType&, Search::StateStackPtr&);
Depth minimumSplitDepth;
- Spinlock spinlock;
- std::condition_variable sleepCondition;
+ Mutex mutex;
+ ConditionVariable sleepCondition;
TimerThread* timer;
};