#ifndef THREAD_H_INCLUDED
#define THREAD_H_INCLUDED
+#include <atomic>
#include <bitset>
#include <condition_variable>
#include <mutex>
#include "pawns.h"
#include "position.h"
#include "search.h"
+#include "thread_win32.h"
struct Thread;
-const int MAX_THREADS = 128;
-const int MAX_SPLITPOINTS_PER_THREAD = 8;
+const size_t MAX_THREADS = 128;
+const size_t MAX_SPLITPOINTS_PER_THREAD = 8;
+const size_t MAX_SLAVES_PER_SPLITPOINT = 4;
+
+class Spinlock {
+
+ std::atomic_int lock;
+
+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)
+ for (int cnt = 0; lock.load(std::memory_order_relaxed) <= 0; ++cnt)
+ if (cnt >= 10000) std::this_thread::yield(); // Be nice to hyperthreading
+ }
+ void release() { lock.store(1, std::memory_order_release); }
+};
+
/// 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;
+ Thread* master;
Depth depth;
Value beta;
int nodeType;
SplitPoint* parentSplitPoint;
// Shared variable data
- std::mutex mutex;
+ Spinlock spinlock;
std::bitset<MAX_THREADS> slavesMask;
volatile bool allSlavesSearching;
volatile uint64_t nodes;
void wait_for(volatile const bool& b);
std::thread nativeThread;
- std::mutex mutex;
- std::condition_variable sleepCondition;
+ Mutex mutex;
+ Spinlock spinlock;
+ ConditionVariable sleepCondition;
volatile bool exit = false;
};
Thread();
virtual void idle_loop();
bool cutoff_occurred() const;
- bool available_to(const Thread* master) const;
+ bool can_join(const SplitPoint* sp) 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);
size_t idx;
int maxPly;
SplitPoint* volatile activeSplitPoint;
- volatile int splitPointsSize;
+ volatile size_t splitPointsSize;
volatile bool searching;
};
struct MainThread : public Thread {
virtual void idle_loop();
+ void join();
volatile bool thinking = true; // Avoid a race with start_thinking()
};
MainThread* main() { return static_cast<MainThread*>(at(0)); }
void read_uci_options();
- Thread* available_slave(const Thread* master) const;
- void wait_for_think_finished();
+ Thread* available_slave(const SplitPoint* sp) const;
void start_thinking(const Position&, const Search::LimitsType&, Search::StateStackPtr&);
Depth minimumSplitDepth;
- std::mutex mutex;
- std::condition_variable sleepCondition;
TimerThread* timer;
};