Value SerialSumTree( TreeNode* root ) {
Value result = root->value;
if( root->left )
result += SerialSumTree(root->left);
if( root->right )
result += SerialSumTree(root->right);
return result;
}
tbb::task* execute() {
tbb::task* next = NULL;
if( !is_continuation ) {
if( root->node_count<1000 ) {
*sum = SerialSumTree(root);
} else {
// Create tasks before spawning any of them.
tbb::task* a = NULL;
tbb::task* b = NULL;
if( root->left )
a = new( allocate_child() ) OptimizedSumTask(root->left,&x);
if( root->right )
b = new( allocate_child() ) OptimizedSumTask(root->right,&y);
recycle_as_continuation();
is_continuation = true;
set_ref_count( (a!=NULL)+(b!=NULL) );
if( a ) {
if( b ) spawn(*b);
} else
a = b;
next = a;
}
} else {
*sum = root->value;
if( root->left ) *sum += x;
if( root->right ) *sum += y;
}
return next;
}
task* execute() {
if( root->node_count<1000 ) {
*sum = SerialSumTree(root);
} else {
Value x, y;
int count = 1;
tbb::task_list list;
if( root->left ) {
++count;
list.push_back( *new( allocate_child() ) SimpleSumTask(root->left,&x) );
}
if( root->right ) {
++count;
list.push_back( *new( allocate_child() ) SimpleSumTask(root->right,&y) );
}
// Argument to set_ref_count is one more than size of the list,
// because spawn_and_wait_for_all expects an augmented ref_count.
set_ref_count(count);
spawn_and_wait_for_all(list);
*sum = root->value;
if( root->left ) *sum += x;
if( root->right ) *sum += y;
}
return NULL;
}
