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/*
Copyright 2005-2011 Intel Corporation. All Rights Reserved.
This file is part of Threading Building Blocks.
Threading Building Blocks is free software; you can redistribute it
and/or modify it under the terms of the GNU General Public License
version 2 as published by the Free Software Foundation.
Threading Building Blocks is distributed in the hope that it will be
useful, but WITHOUT ANY WARRANTY; without even the implied warranty
of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with Threading Building Blocks; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
As a special exception, you may use this file as part of a free software
library without restriction. Specifically, if other files instantiate
templates or use macros or inline functions from this file, or you compile
this file and link it with other files to produce an executable, this
file does not by itself cause the resulting executable to be covered by
the GNU General Public License. This exception does not however
invalidate any other reasons why the executable file might be covered by
the GNU General Public License.
*/
#ifndef TREE_MAKER_H_
#define TREE_MAKER_H_
#include "tbb/tick_count.h"
#include "tbb/task.h"
static double Pi = 3.14159265358979;
const bool tbbmalloc = true;
const bool stdmalloc = false;
template<bool use_tbbmalloc>
class TreeMaker {
class SubTreeCreationTask: public tbb::task {
TreeNode*& my_root;
bool is_continuation;
typedef TreeMaker<use_tbbmalloc> MyTreeMaker;
public:
SubTreeCreationTask( TreeNode*& root, long number_of_nodes ) : my_root(root), is_continuation(false) {
my_root = MyTreeMaker::allocate_node();
my_root->node_count = number_of_nodes;
my_root->value = Value(Pi*number_of_nodes);
}
tbb::task* execute() {
tbb::task* next = NULL;
if( !is_continuation ) {
long subtree_size = my_root->node_count - 1;
if( subtree_size<1000 ) { /* grainsize */
my_root->left = MyTreeMaker::do_in_one_thread(subtree_size/2);
my_root->right = MyTreeMaker::do_in_one_thread(subtree_size - subtree_size/2);
} else {
// Create tasks before spawning any of them.
tbb::task* a = new( allocate_child() ) SubTreeCreationTask(my_root->left,subtree_size/2);
tbb::task* b = new( allocate_child() ) SubTreeCreationTask(my_root->right,subtree_size - subtree_size/2);
recycle_as_continuation();
is_continuation = true;
set_ref_count(2);
spawn(*b);
next = a;
}
}
return next;
}
};
public:
static TreeNode* allocate_node() {
return use_tbbmalloc? tbb::scalable_allocator<TreeNode>().allocate(1) : new TreeNode;
}
static TreeNode* do_in_one_thread( long number_of_nodes ) {
if( number_of_nodes==0 ) {
return NULL;
} else {
TreeNode* n = allocate_node();
n->node_count = number_of_nodes;
n->value = Value(Pi*number_of_nodes);
--number_of_nodes;
n->left = do_in_one_thread( number_of_nodes/2 );
n->right = do_in_one_thread( number_of_nodes - number_of_nodes/2 );
return n;
}
}
static TreeNode* do_in_parallel( long number_of_nodes ) {
TreeNode* root_node;
SubTreeCreationTask& a = *new(tbb::task::allocate_root()) SubTreeCreationTask(root_node, number_of_nodes);
tbb::task::spawn_root_and_wait(a);
return root_node;
}
static TreeNode* create_and_time( long number_of_nodes, bool silent=false ) {
tbb::tick_count t0, t1;
TreeNode* root = allocate_node();
root->node_count = number_of_nodes;
root->value = Value(Pi*number_of_nodes);
--number_of_nodes;
t0 = tbb::tick_count::now();
root->left = do_in_one_thread( number_of_nodes/2 );
t1 = tbb::tick_count::now();
if ( !silent ) printf ("%24s: time = %.1f msec\n", "half created serially", (t1-t0).seconds()*1000);
t0 = tbb::tick_count::now();
root->right = do_in_parallel( number_of_nodes - number_of_nodes/2 );
t1 = tbb::tick_count::now();
if ( !silent ) printf ("%24s: time = %.1f msec\n", "half done in parallel", (t1-t0).seconds()*1000);
return root;
}
};
#endif // TREE_MAKER_H_
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