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Diffstat (limited to 'src/boost/libs/compute/perf/perf_tbb_merge.cpp')
-rw-r--r-- | src/boost/libs/compute/perf/perf_tbb_merge.cpp | 95 |
1 files changed, 95 insertions, 0 deletions
diff --git a/src/boost/libs/compute/perf/perf_tbb_merge.cpp b/src/boost/libs/compute/perf/perf_tbb_merge.cpp new file mode 100644 index 00000000..a7aa814e --- /dev/null +++ b/src/boost/libs/compute/perf/perf_tbb_merge.cpp @@ -0,0 +1,95 @@ +//---------------------------------------------------------------------------// +// Copyright (c) 2014 Kyle Lutz <kyle.r.lutz@gmail.com> +// +// Distributed under the Boost Software License, Version 1.0 +// See accompanying file LICENSE_1_0.txt or copy at +// http://www.boost.org/LICENSE_1_0.txt +// +// See http://boostorg.github.com/compute for more information. +//---------------------------------------------------------------------------// + +#include <algorithm> +#include <iostream> +#include <vector> + +#include <tbb/parallel_for.h> + +#include "perf.hpp" + +// example from: http://www.threadingbuildingblocks.org/docs/help/reference/algorithms/parallel_for_func.htm +using namespace tbb; + +template<typename Iterator> +struct ParallelMergeRange { + static size_t grainsize; + Iterator begin1, end1; // [begin1,end1) is 1st sequence to be merged + Iterator begin2, end2; // [begin2,end2) is 2nd sequence to be merged + Iterator out; // where to put merged sequence + bool empty() const {return (end1-begin1)+(end2-begin2)==0;} + bool is_divisible() const { + return (std::min)( end1-begin1, end2-begin2 ) > grainsize; + } + ParallelMergeRange( ParallelMergeRange& r, split ) { + if( r.end1-r.begin1 < r.end2-r.begin2 ) { + std::swap(r.begin1,r.begin2); + std::swap(r.end1,r.end2); + } + Iterator m1 = r.begin1 + (r.end1-r.begin1)/2; + Iterator m2 = std::lower_bound( r.begin2, r.end2, *m1 ); + begin1 = m1; + begin2 = m2; + end1 = r.end1; + end2 = r.end2; + out = r.out + (m1-r.begin1) + (m2-r.begin2); + r.end1 = m1; + r.end2 = m2; + } + ParallelMergeRange( Iterator begin1_, Iterator end1_, + Iterator begin2_, Iterator end2_, + Iterator out_ ) : + begin1(begin1_), end1(end1_), + begin2(begin2_), end2(end2_), out(out_) + {} +}; + +template<typename Iterator> +size_t ParallelMergeRange<Iterator>::grainsize = 1000; + +template<typename Iterator> +struct ParallelMergeBody { + void operator()( ParallelMergeRange<Iterator>& r ) const { + std::merge( r.begin1, r.end1, r.begin2, r.end2, r.out ); + } +}; + +template<typename Iterator> +void ParallelMerge( Iterator begin1, Iterator end1, Iterator begin2, Iterator end2, Iterator out ) { + parallel_for( + ParallelMergeRange<Iterator>(begin1,end1,begin2,end2,out), + ParallelMergeBody<Iterator>(), + simple_partitioner() + ); +} + +int main(int argc, char *argv[]) +{ + perf_parse_args(argc, argv); + + std::cout << "size: " << PERF_N << std::endl; + std::vector<int> v1 = generate_random_vector<int>(PERF_N / 2); + std::vector<int> v2 = generate_random_vector<int>(PERF_N / 2); + std::vector<int> v3(PERF_N); + + std::sort(v1.begin(), v1.end()); + std::sort(v2.begin(), v2.end()); + + perf_timer t; + for(size_t trial = 0; trial < PERF_TRIALS; trial++){ + t.start(); + ParallelMerge(v1.begin(), v1.end(), v2.begin(), v2.end(), v3.begin()); + t.stop(); + } + std::cout << "time: " << t.min_time() / 1e6 << " ms" << std::endl; + + return 0; +} |