#ifndef THREAD_H_INCLUDED
#define THREAD_H_INCLUDED
+#include <atomic>
#include <bitset>
+#include <condition_variable>
+#include <mutex>
+#include <thread>
#include <vector>
#include "material.h"
struct Thread;
-const int MAX_THREADS = 128;
-const int MAX_SPLITPOINTS_PER_THREAD = 8;
-const int MAX_SLAVES_PER_SPLITPOINT = 4;
-
-/// Mutex and ConditionVariable struct are wrappers of the low level locking
-/// machinery and are modeled after the corresponding C++11 classes.
-
-struct Mutex {
- Mutex() { lock_init(l); }
- ~Mutex() { lock_destroy(l); }
-
- void lock() { lock_grab(l); }
- void unlock() { lock_release(l); }
-
-private:
- friend struct ConditionVariable;
-
- Lock l;
-};
-
-struct ConditionVariable {
- ConditionVariable() { cond_init(c); }
- ~ConditionVariable() { cond_destroy(c); }
-
- 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); }
-
-private:
- WaitCondition c;
-};
-
+const size_t MAX_THREADS = 128;
+const size_t MAX_SPLITPOINTS_PER_THREAD = 8;
+const size_t MAX_SLAVES_PER_SPLITPOINT = 4;
/// SplitPoint struct stores information shared by the threads searching in
/// parallel below the same split point. It is populated at splitting time.
// Const data after split point has been setup
const Position* pos;
Search::Stack* ss;
- Thread* masterThread;
- int spLevel;
+ Thread* master;
Depth depth;
Value beta;
int nodeType;
SplitPoint* parentSplitPoint;
// Shared variable data
- Mutex mutex;
+ std::mutex mutex;
std::bitset<MAX_THREADS> slavesMask;
- int slavesCount;
volatile bool allSlavesSearching;
volatile uint64_t nodes;
volatile Value alpha;
};
+/// Spinlock class wraps low level atomic operations to provide spin lock functionality
+
+class Spinlock {
+
+ std::atomic_flag lock;
+
+public:
+ Spinlock() { std::atomic_flag_clear(&lock); }
+ void acquire() { while (lock.test_and_set(std::memory_order_acquire)) {} }
+ void release() { lock.clear(std::memory_order_release); }
+};
+
+
/// ThreadBase struct is the base of the hierarchy from where we derive all the
/// specialized thread classes.
struct ThreadBase {
- ThreadBase() : handle(NativeHandle()), exit(false) {}
- virtual ~ThreadBase() {}
+ virtual ~ThreadBase() = default;
virtual void idle_loop() = 0;
void notify_one();
void wait_for(volatile const bool& b);
- Mutex mutex;
- ConditionVariable sleepCondition;
- NativeHandle handle;
- volatile bool exit;
+ std::thread nativeThread;
+ std::mutex mutex;
+ std::condition_variable sleepCondition;
+ volatile bool exit = false;
};
size_t idx;
int maxPly;
SplitPoint* volatile activeSplitPoint;
- volatile int splitPointsSize;
+ volatile size_t splitPointsSize;
volatile bool searching;
};
/// 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;
+ volatile bool thinking = true; // Avoid a race with start_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;
+ bool run = false;
};
void start_thinking(const Position&, const Search::LimitsType&, Search::StateStackPtr&);
Depth minimumSplitDepth;
- Mutex mutex;
- ConditionVariable sleepCondition;
+ std::mutex mutex;
+ std::condition_variable sleepCondition;
TimerThread* timer;
};