/// Types
enum NodeType { NonPV, PV };
+ // Set to true to force running with one thread.
+ // Used for debugging SMP code.
+ const bool FakeSplit = false;
+
// ThreadsManager class is used to handle all the threads related stuff in search,
// init, starting, parking and, the most important, launching a slave thread at a
// split point are what this class does. All the access to shared thread data is
alpha = value;
update_pv(ss, ply);
+
if (value == value_mate_in(ply + 1))
ss[ply].mateKiller = move;
}
&& TM.available_thread_exists(threadID)
&& !AbortSearch
&& !TM.thread_should_stop(threadID)
- && TM.split<false>(pos, ss, ply, &alpha, beta, &bestValue,
- depth, mateThreat, &moveCount, &mp, threadID, PvNode))
- break;
-
- // Uncomment to debug sp_search() in single thread mode
- /*
- if ( bestValue < beta
- && depth >= 4
- && Iteration <= 99
- && !AbortSearch
- && !TM.thread_should_stop(threadID)
- && TM.split<true>(pos, ss, ply, &alpha, beta, &bestValue,
- depth, mateThreat, &moveCount, &mp, threadID, PvNode))
+ && TM.split<FakeSplit>(pos, ss, ply, &alpha, beta, &bestValue, depth,
+ mateThreat, &moveCount, &mp, threadID, PvNode))
break;
- */
}
// Step 19. Check for mate and stalemate
void sp_search(SplitPoint* sp, int threadID) {
assert(threadID >= 0 && threadID < TM.active_threads());
+ assert(TM.active_threads() > 1);
StateInfo st;
Move move;
lock_grab(&(sp->lock));
while ( sp->bestValue < sp->beta
- && !TM.thread_should_stop(threadID)
- && (move = sp->mp->get_next_move()) != MOVE_NONE)
+ && (move = sp->mp->get_next_move()) != MOVE_NONE
+ && !TM.thread_should_stop(threadID))
{
moveCount = ++sp->moves;
lock_release(&(sp->lock));
{
Value localAlpha = sp->alpha;
value = -search<NonPV>(pos, ss, -(localAlpha+1), -localAlpha, newDepth-ss[sp->ply].reduction, sp->ply+1, true, threadID);
- doFullDepthSearch = (value > localAlpha && !TM.thread_should_stop(threadID));
+ doFullDepthSearch = (value > localAlpha);
}
}
Value localAlpha = sp->alpha;
value = -search<NonPV>(pos, ss, -(localAlpha+1), -localAlpha, newDepth, sp->ply+1, true, threadID);
- if (PvNode && value > localAlpha && value < sp->beta && !TM.thread_should_stop(threadID))
+ if (PvNode && value > localAlpha && value < sp->beta)
value = -search<PV>(pos, ss, -sp->beta, -sp->alpha, newDepth, sp->ply+1, false, threadID);
}
sp->alpha = value;
sp_update_pv(sp->parentSstack, ss, sp->ply);
-
- if (PvNode && value == value_mate_in(sp->ply + 1))
- ss[sp->ply].mateKiller = move;
}
}
}
/* Here we have the lock still grabbed */
sp->slaves[threadID] = 0;
- sp->cpus--;
lock_release(&(sp->lock));
}
}
ss[ply].init(ply);
ss[ply + 2].initKillers();
-
-
}
// update_pv() is called whenever a search returns a value > alpha.
threads[threadID].state = THREAD_AVAILABLE;
}
- // If this thread is the master of a split point and all threads have
+ // If this thread is the master of a split point and all slaves have
// finished their work at this split point, return from the idle loop.
- if (sp && sp->cpus == 0)
+ int i = 0;
+ for ( ; sp && i < ActiveThreads && !sp->slaves[i]; i++) {}
+
+ if (i == ActiveThreads)
{
- // Because sp->cpus is decremented under lock protection,
- // be sure sp->lock has been released before to proceed.
+ // Because sp->slaves[] is reset under lock protection,
+ // be sure sp->lock has been released before to return.
lock_grab(&(sp->lock));
lock_release(&(sp->lock));
// data that must be copied to the helper threads (the current position and
// search stack, alpha, beta, the search depth, etc.), and we tell our
// helper threads that they have been assigned work. This will cause them
- // to instantly leave their idle loops and call sp_search_pv(). When all
- // threads have returned from sp_search_pv (or, equivalently, when
- // splitPoint->cpus becomes 0), split() returns true.
+ // to instantly leave their idle loops and call sp_search(). When all
+ // threads have returned from sp_search() then split() returns true.
template <bool Fake>
- bool ThreadsManager::split(const Position& p, SearchStack* sstck, int ply,
- Value* alpha, const Value beta, Value* bestValue,
- Depth depth, bool mateThreat, int* moves, MovePicker* mp, int master, bool pvNode) {
-
+ bool ThreadsManager::split(const Position& p, SearchStack* sstck, int ply, Value* alpha,
+ const Value beta, Value* bestValue, Depth depth, bool mateThreat,
+ int* moves, MovePicker* mp, int master, bool pvNode) {
assert(p.is_ok());
assert(sstck != NULL);
assert(ply >= 0 && ply < PLY_MAX);
assert(beta <= VALUE_INFINITE);
assert(depth > Depth(0));
assert(master >= 0 && master < ActiveThreads);
- assert(Fake || ActiveThreads > 1);
+ assert(ActiveThreads > 1);
SplitPoint* splitPoint;
// If no other thread is available to help us, or if we have too many
// active split points, don't split.
- if ( (!Fake && !available_thread_exists(master))
+ if ( !available_thread_exists(master)
|| threads[master].activeSplitPoints >= ACTIVE_SPLIT_POINTS_MAX)
{
lock_release(&MPLock);
splitPoint->master = master;
splitPoint->mp = mp;
splitPoint->moves = *moves;
- splitPoint->cpus = 1;
splitPoint->pos = &p;
splitPoint->parentSstack = sstck;
for (int i = 0; i < ActiveThreads; i++)
// If we are here it means we are not available
assert(threads[master].state != THREAD_AVAILABLE);
+ int workersCnt = 1; // At least the master is included
+
// Allocate available threads setting state to THREAD_BOOKED
- for (int i = 0; i < ActiveThreads && splitPoint->cpus < MaxThreadsPerSplitPoint; i++)
- if (!Fake && thread_is_available(i, master))
+ for (int i = 0; !Fake && i < ActiveThreads && workersCnt < MaxThreadsPerSplitPoint; i++)
+ if (thread_is_available(i, master))
{
threads[i].state = THREAD_BOOKED;
threads[i].splitPoint = splitPoint;
splitPoint->slaves[i] = 1;
- splitPoint->cpus++;
+ workersCnt++;
}
- assert(Fake || splitPoint->cpus > 1);
+ assert(Fake || workersCnt > 1);
// We can release the lock because slave threads are already booked and master is not available
lock_release(&MPLock);
// 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
- // (i.e. when splitPoint->cpus == 0).
+ // loop when all threads have finished their work at this split point.
idle_loop(master, splitPoint);
// We have returned from the idle loop, which means that all threads are
projects / stockfish / blobdiff