// Pointer 'this_sp' is not null only if we are called from split(), and not
// at the thread creation. This means we are the split point's master.
- SplitPoint* this_sp = splitPointsSize ? activeSplitPoint : NULL;
+ SplitPoint* this_sp = activeSplitPoint;
- assert(!this_sp || (this_sp->masterThread == this && searching));
+ assert(!this_sp || (this_sp->master == this && searching));
while (!exit)
{
Threads.mutex.lock();
assert(activeSplitPoint);
+
SplitPoint* sp = activeSplitPoint;
Threads.mutex.unlock();
// Wake up the master thread so to allow it to return from the idle
// loop in case we are the last slave of the split point.
- if ( this != sp->masterThread
- && sp->slavesMask.none())
+ if (this != sp->master && sp->slavesMask.none())
{
- assert(!sp->masterThread->searching);
- sp->masterThread->notify_one();
+ assert(!sp->master->searching);
+
+ sp->master->notify_one();
}
// After releasing the lock we can't access any SplitPoint related data
// Try to late join to another split point if none of its slaves has
// already finished.
SplitPoint* bestSp = NULL;
- Thread* bestThread = NULL;
int bestScore = INT_MAX;
for (size_t i = 0; i < Threads.size(); ++i)
{
- const int size = Threads[i]->splitPointsSize; // Local copy
+ const size_t size = Threads[i]->splitPointsSize; // Local copy
sp = size ? &Threads[i]->splitPoints[size - 1] : NULL;
if ( sp
{
assert(this != Threads[i]);
assert(!(this_sp && this_sp->slavesMask.none()));
+ assert(Threads.size() > 2);
- // Compute the recursive split points chain size
+ // Prefer to join to SP with few parents to reduce the probability
+ // that a cut-off occurs above us, and hence we waste our work.
int level = -1;
for (SplitPoint* spp = Threads[i]->activeSplitPoint; spp; spp = spp->parentSplitPoint)
level++;
if (score < bestScore)
{
bestSp = sp;
- bestThread = Threads[i];
bestScore = score;
}
}
if ( sp->allSlavesSearching
&& sp->slavesMask.count() < MAX_SLAVES_PER_SPLITPOINT
- && available_to(bestThread))
+ && available_to(sp->master))
{
sp->slavesMask.set(idx);
activeSplitPoint = sp;
}
}
- // Grab the lock to avoid races with Thread::notify_one()
+ // Avoid races with notify_one() fired from last slave of the split point
mutex.lock();
// If we are master and all slaves have finished then exit idle_loop
// Loop across all split points and sum accumulated SplitPoint nodes plus
// all the currently active positions nodes.
for (size_t i = 0; i < Threads.size(); ++i)
- for (int j = 0; j < Threads[i]->splitPointsSize; ++j)
+ for (size_t j = 0; j < Threads[i]->splitPointsSize; ++j)
{
SplitPoint& sp = Threads[i]->splitPoints[j];