#ifndef THREAD_H_INCLUDED
#define THREAD_H_INCLUDED
+#include <atomic>
#include <bitset>
#include <condition_variable>
#include <mutex>
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;
+
+/// 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); }
+};
+
/// 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;
size_t idx;
int maxPly;
SplitPoint* volatile activeSplitPoint;
- volatile int splitPointsSize;
+ volatile size_t splitPointsSize;
volatile bool searching;
};
void start_thinking(const Position&, const Search::LimitsType&, Search::StateStackPtr&);
Depth minimumSplitDepth;
- std::mutex mutex;
+ Spinlock spinlock;
std::condition_variable sleepCondition;
TimerThread* timer;
};