Edit: /usr/include/stxxl/bits/parallel.h (6315B)
/***************************************************************************
* include/stxxl/bits/parallel.h
*
* Part of the STXXL. See http://stxxl.sourceforge.net
*
* Copyright (C) 2008-2010 Andreas Beckmann
* Copyright (C) 2011 Johannes Singler
*
* 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)
**************************************************************************/
#ifndef STXXL_PARALLEL_HEADER
#define STXXL_PARALLEL_HEADER
#include
#undef STXXL_PARALLEL
#undef STXXL_PARALLEL_MODE
#if defined(_GLIBCXX_PARALLEL) || STXXL_PARALLEL_MODE_EXPLICIT
#define STXXL_PARALLEL_MODE
#endif
#if defined(STXXL_PARALLEL_MODE)
#define STXXL_PARALLEL 1
#else
#define STXXL_PARALLEL 0
#endif
#include
#ifdef STXXL_PARALLEL_MODE
#include
#endif
#if STXXL_PARALLEL
#include
#endif
#include
#include
#include
#if defined(_GLIBCXX_PARALLEL)
//use _STXXL_FORCE_SEQUENTIAL to tag calls which are not worthwhile parallelizing
#define _STXXL_FORCE_SEQUENTIAL , __gnu_parallel::sequential_tag()
#else
#define _STXXL_FORCE_SEQUENTIAL
#endif
#if 0
// sorting triggers is done sequentially
#define _STXXL_SORT_TRIGGER_FORCE_SEQUENTIAL _STXXL_FORCE_SEQUENTIAL
#else
// sorting triggers may be parallelized
#define _STXXL_SORT_TRIGGER_FORCE_SEQUENTIAL
#endif
#if !STXXL_PARALLEL
#undef STXXL_PARALLEL_MULTIWAY_MERGE
#define STXXL_PARALLEL_MULTIWAY_MERGE 0
#endif
#if defined(STXXL_PARALLEL_MODE) && ((__GNUC__ * 10000 + __GNUC_MINOR__ * 100) < 40400)
#undef STXXL_PARALLEL_MULTIWAY_MERGE
#define STXXL_PARALLEL_MULTIWAY_MERGE 0
#endif
#if !defined(STXXL_PARALLEL_MULTIWAY_MERGE)
#define STXXL_PARALLEL_MULTIWAY_MERGE 1
#endif
#if !defined(STXXL_NOT_CONSIDER_SORT_MEMORY_OVERHEAD)
#define STXXL_NOT_CONSIDER_SORT_MEMORY_OVERHEAD 0
#endif
#if STXXL_PARALLEL_MODE_EXPLICIT
#include
#else
#include
#endif
STXXL_BEGIN_NAMESPACE
inline unsigned sort_memory_usage_factor()
{
#if STXXL_PARALLEL && !STXXL_NOT_CONSIDER_SORT_MEMORY_OVERHEAD && defined(STXXL_PARALLEL_MODE)
return (__gnu_parallel::_Settings::get().sort_algorithm == __gnu_parallel::MWMS && omp_get_max_threads() > 1) ? 2 : 1; //memory overhead for multiway mergesort
#else
return 1; //no overhead
#endif
}
inline void check_sort_settings()
{
#if STXXL_PARALLEL && defined(STXXL_PARALLEL_MODE) && !defined(STXXL_NO_WARN_OMP_NESTED)
static bool did_warn = false;
if (!did_warn) {
if (__gnu_parallel::_Settings::get().sort_algorithm != __gnu_parallel::MWMS) {
if (omp_get_max_threads() <= 2) {
did_warn = true; // no problem with at most 2 threads, no need to check again
} else if (!omp_get_nested()) {
STXXL_ERRMSG("Inefficient settings detected. To get full potential from your CPU it is recommended to set OMP_NESTED=TRUE in the environment.");
did_warn = true;
}
}
}
#else
// nothing to check
#endif
}
inline bool do_parallel_merge()
{
#if STXXL_PARALLEL_MULTIWAY_MERGE && defined(STXXL_PARALLEL_MODE)
return !stxxl::SETTINGS::native_merge && omp_get_max_threads() >= 1;
#else
return false;
#endif
}
namespace potentially_parallel {
#if STXXL_PARALLEL_MODE_EXPLICIT
using __gnu_parallel::sort;
using __gnu_parallel::random_shuffle;
#else
using std::sort;
using std::random_shuffle;
#endif
} // namespace potentially_parallel
namespace parallel {
#if STXXL_PARALLEL
/*! Multi-way merging dispatcher.
* @param seqs_begin Begin iterator of iterator pair input sequence.
* @param seqs_end End iterator of iterator pair input sequence.
* @param target Begin iterator out output sequence.
* @param comp Comparator.
* @param length Maximum length to merge.
* @return End iterator of output sequence.
*/
template
RandomAccessIterator3
multiway_merge(RandomAccessIteratorPairIterator seqs_begin,
RandomAccessIteratorPairIterator seqs_end,
RandomAccessIterator3 target,
Comparator comp,
DiffType length)
{
#if defined(STXXL_PARALLEL_MODE) && ((__GNUC__ * 10000 + __GNUC_MINOR__ * 100) >= 40400)
return __gnu_parallel::multiway_merge(seqs_begin, seqs_end, target, length, comp);
#elif defined(STXXL_PARALLEL_MODE)
return __gnu_parallel::multiway_merge(seqs_begin, seqs_end, target, comp, length);
#else
#error "no implementation found for multiway_merge()"
#endif
}
/*! Multi-way merging front-end.
* @param seqs_begin Begin iterator of iterator pair input sequence.
* @param seqs_end End iterator of iterator pair input sequence.
* @param target Begin iterator out output sequence.
* @param comp Comparator.
* @param length Maximum length to merge.
* @return End iterator of output sequence.
* @pre For each @c i, @c seqs_begin[i].second must be the end marker of the sequence, but also reference the one more sentinel element.
*/
template
RandomAccessIterator3
multiway_merge_sentinel(RandomAccessIteratorPairIterator seqs_begin,
RandomAccessIteratorPairIterator seqs_end,
RandomAccessIterator3 target,
Comparator comp,
DiffType length)
{
#if defined(STXXL_PARALLEL_MODE) && ((__GNUC__ * 10000 + __GNUC_MINOR__ * 100) >= 40400)
return __gnu_parallel::multiway_merge_sentinels(seqs_begin, seqs_end, target, length, comp);
#elif defined(STXXL_PARALLEL_MODE)
return __gnu_parallel::multiway_merge_sentinels(seqs_begin, seqs_end, target, comp, length);
#else
#error "no implementation found for multiway_merge_sentinel()"
#endif
}
#endif
} // namespace parallel
STXXL_END_NAMESPACE
#endif // !STXXL_PARALLEL_HEADER
// vim: et:ts=4:sw=4