--- /dev/null
+// -*- C++ -*-
+
+// Copyright (C) 2007, 2008, 2009 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library. This library is free
+// software; you can redistribute it and/or modify it under the terms
+// of the GNU General Public License as published by the Free Software
+// Foundation; either version 3, or (at your option) any later
+// version.
+
+// This library 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.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file parallel/settings.h
+ * @brief Runtime settings and tuning parameters, heuristics to decide
+ * whether to use parallelized algorithms.
+ * This file is a GNU parallel extension to the Standard C++ Library.
+ *
+ * @section parallelization_decision
+ * The decision whether to run an algorithm in parallel.
+ *
+ * There are several ways the user can switch on and off the parallel
+ * execution of an algorithm, both at compile- and run-time.
+ *
+ * Only sequential execution can be forced at compile-time. This
+ * reduces code size and protects code parts that have
+ * non-thread-safe side effects.
+ *
+ * Ultimately, forcing parallel execution at compile-time makes
+ * sense. Often, the sequential algorithm implementation is used as
+ * a subroutine, so no reduction in code size can be achieved. Also,
+ * the machine the program is run on might have only one processor
+ * core, so to avoid overhead, the algorithm is executed
+ * sequentially.
+ *
+ * To force sequential execution of an algorithm ultimately at
+ * compile-time, the user must add the tag
+ * __gnu_parallel::sequential_tag() to the end of the parameter list,
+ * e. g.
+ *
+ * \code
+ * std::sort(v.begin(), v.end(), __gnu_parallel::sequential_tag());
+ * \endcode
+ *
+ * This is compatible with all overloaded algorithm variants. No
+ * additional code will be instantiated, at all. The same holds for
+ * most algorithm calls with iterators not providing random access.
+ *
+ * If the algorithm call is not forced to be executed sequentially
+ * at compile-time, the decision is made at run-time.
+ * The global variable __gnu_parallel::_Settings::algorithm_strategy
+ * is checked. It is a tristate variable corresponding to:
+ *
+ * a. force_sequential, meaning the sequential algorithm is executed.
+ * b. force_parallel, meaning the parallel algorithm is executed.
+ * c. heuristic
+ *
+ * For heuristic, the parallel algorithm implementation is called
+ * only if the input size is sufficiently large. For most
+ * algorithms, the input size is the (combined) length of the input
+ * sequence(s). The threshold can be set by the user, individually
+ * for each algorithm. The according variables are called
+ * __gnu_parallel::_Settings::[algorithm]_minimal_n .
+ *
+ * For some of the algorithms, there are even more tuning options,
+ * e. g. the ability to choose from multiple algorithm variants. See
+ * below for details.
+ */
+
+// Written by Johannes Singler and Felix Putze.
+
+#ifndef _GLIBCXX_PARALLEL_SETTINGS_H
+#define _GLIBCXX_PARALLEL_SETTINGS_H 1
+
+#include <parallel/types.h>
+
+/**
+ * @brief Determine at compile(?)-time if the parallel variant of an
+ * algorithm should be called.
+ * @param c A condition that is convertible to bool that is overruled by
+ * __gnu_parallel::_Settings::algorithm_strategy. Usually a decision
+ * based on the input size.
+ */
+#define _GLIBCXX_PARALLEL_CONDITION(c) (__gnu_parallel::_Settings::get().algorithm_strategy != __gnu_parallel::force_sequential && ((__gnu_parallel::get_max_threads() > 1 && (c)) || __gnu_parallel::_Settings::get().algorithm_strategy == __gnu_parallel::force_parallel))
+
+/*
+inline bool
+parallel_condition(bool c)
+{
+ bool ret = false;
+ const _Settings& s = _Settings::get();
+ if (s.algorithm_strategy != force_seqential)
+ {
+ if (s.algorithm_strategy == force_parallel)
+ ret = true;
+ else
+ ret = get_max_threads() > 1 && c;
+ }
+ return ret;
+}
+*/
+
+namespace __gnu_parallel
+{
+ /// class _Settings
+ /// Run-time settings for the parallel mode, including all tunable parameters.
+ struct _Settings
+ {
+ _AlgorithmStrategy algorithm_strategy;
+
+ _SortAlgorithm sort_algorithm;
+ _PartialSumAlgorithm partial_sum_algorithm;
+ _MultiwayMergeAlgorithm multiway_merge_algorithm;
+ _FindAlgorithm find_algorithm;
+
+ _SplittingAlgorithm sort_splitting;
+ _SplittingAlgorithm merge_splitting;
+ _SplittingAlgorithm multiway_merge_splitting;
+
+ // Per-algorithm settings.
+
+ /// Minimal input size for accumulate.
+ sequence_index_t accumulate_minimal_n;
+
+ /// Minimal input size for adjacent_difference.
+ unsigned int adjacent_difference_minimal_n;
+
+ /// Minimal input size for count and count_if.
+ sequence_index_t count_minimal_n;
+
+ /// Minimal input size for fill.
+ sequence_index_t fill_minimal_n;
+
+ /// Block size increase factor for find.
+ double find_increasing_factor;
+
+ /// Initial block size for find.
+ sequence_index_t find_initial_block_size;
+
+ /// Maximal block size for find.
+ sequence_index_t find_maximum_block_size;
+
+ /// Start with looking for this many elements sequentially, for find.
+ sequence_index_t find_sequential_search_size;
+
+ /// Minimal input size for for_each.
+ sequence_index_t for_each_minimal_n;
+
+ /// Minimal input size for generate.
+ sequence_index_t generate_minimal_n;
+
+ /// Minimal input size for max_element.
+ sequence_index_t max_element_minimal_n;
+
+ /// Minimal input size for merge.
+ sequence_index_t merge_minimal_n;
+
+ /// Oversampling factor for merge.
+ unsigned int merge_oversampling;
+
+ /// Minimal input size for min_element.
+ sequence_index_t min_element_minimal_n;
+
+ /// Minimal input size for multiway_merge.
+ sequence_index_t multiway_merge_minimal_n;
+
+ /// Oversampling factor for multiway_merge.
+ int multiway_merge_minimal_k;
+
+ /// Oversampling factor for multiway_merge.
+ unsigned int multiway_merge_oversampling;
+
+ /// Minimal input size for nth_element.
+ sequence_index_t nth_element_minimal_n;
+
+ /// Chunk size for partition.
+ sequence_index_t partition_chunk_size;
+
+ /// Chunk size for partition, relative to input size. If > 0.0,
+ /// this value overrides partition_chunk_size.
+ double partition_chunk_share;
+
+ /// Minimal input size for partition.
+ sequence_index_t partition_minimal_n;
+
+ /// Minimal input size for partial_sort.
+ sequence_index_t partial_sort_minimal_n;
+
+ /// Ratio for partial_sum. Assume "sum and write result" to be
+ /// this factor slower than just "sum".
+ float partial_sum_dilation;
+
+ /// Minimal input size for partial_sum.
+ unsigned int partial_sum_minimal_n;
+
+ /// Minimal input size for random_shuffle.
+ unsigned int random_shuffle_minimal_n;
+
+ /// Minimal input size for replace and replace_if.
+ sequence_index_t replace_minimal_n;
+
+ /// Minimal input size for set_difference.
+ sequence_index_t set_difference_minimal_n;
+
+ /// Minimal input size for set_intersection.
+ sequence_index_t set_intersection_minimal_n;
+
+ /// Minimal input size for set_symmetric_difference.
+ sequence_index_t set_symmetric_difference_minimal_n;
+
+ /// Minimal input size for set_union.
+ sequence_index_t set_union_minimal_n;
+
+ /// Minimal input size for parallel sorting.
+ sequence_index_t sort_minimal_n;
+
+ /// Oversampling factor for parallel std::sort (MWMS).
+ unsigned int sort_mwms_oversampling;
+
+ /// Such many samples to take to find a good pivot (quicksort).
+ unsigned int sort_qs_num_samples_preset;
+
+ /// Maximal subsequence length to switch to unbalanced base case.
+ /// Applies to std::sort with dynamically load-balanced quicksort.
+ sequence_index_t sort_qsb_base_case_maximal_n;
+
+ /// Minimal input size for parallel std::transform.
+ sequence_index_t transform_minimal_n;
+
+ /// Minimal input size for unique_copy.
+ sequence_index_t unique_copy_minimal_n;
+
+ sequence_index_t workstealing_chunk_size;
+
+ // Hardware dependent tuning parameters.
+
+ /// Size of the L1 cache in bytes (underestimation).
+ unsigned long long L1_cache_size;
+
+ /// Size of the L2 cache in bytes (underestimation).
+ unsigned long long L2_cache_size;
+
+ /// Size of the Translation Lookaside Buffer (underestimation).
+ unsigned int TLB_size;
+
+ /// Overestimation of cache line size. Used to avoid false
+ /// sharing, i. e. elements of different threads are at least this
+ /// amount apart.
+ unsigned int cache_line_size;
+
+ // Statistics.
+
+ /// The number of stolen ranges in load-balanced quicksort.
+ sequence_index_t qsb_steals;
+
+ /// Get the global settings.
+ static const _Settings&
+ get() throw();
+
+ /// Set the global settings.
+ static void
+ set(_Settings&) throw();
+
+ explicit
+ _Settings() : algorithm_strategy(heuristic), sort_algorithm(MWMS), partial_sum_algorithm(LINEAR), multiway_merge_algorithm(LOSER_TREE), find_algorithm(CONSTANT_SIZE_BLOCKS), sort_splitting(EXACT), merge_splitting(EXACT), multiway_merge_splitting(EXACT), accumulate_minimal_n(1000), adjacent_difference_minimal_n(1000), count_minimal_n(1000), fill_minimal_n(1000), find_increasing_factor(2.0), find_initial_block_size(256), find_maximum_block_size(8192), find_sequential_search_size(256), for_each_minimal_n(1000), generate_minimal_n(1000), max_element_minimal_n(1000), merge_minimal_n(1000), merge_oversampling(10), min_element_minimal_n(1000), multiway_merge_minimal_n(1000), multiway_merge_minimal_k(2), multiway_merge_oversampling(10), nth_element_minimal_n(1000), partition_chunk_size(1000), partition_chunk_share(0.0), partition_minimal_n(1000), partial_sort_minimal_n(1000), partial_sum_dilation(1.0f), partial_sum_minimal_n(1000), random_shuffle_minimal_n(1000), replace_minimal_n(1000), set_difference_minimal_n(1000), set_intersection_minimal_n(1000), set_symmetric_difference_minimal_n(1000), set_union_minimal_n(1000), sort_minimal_n(1000), sort_mwms_oversampling(10), sort_qs_num_samples_preset(100), sort_qsb_base_case_maximal_n(100), transform_minimal_n(1000), unique_copy_minimal_n(10000), workstealing_chunk_size(100), L1_cache_size(16 << 10), L2_cache_size(256 << 10), TLB_size(128), cache_line_size(64), qsb_steals(0)
+ { }
+ };
+}
+
+#endif /* _GLIBCXX_PARALLEL_SETTINGS_H */
projects / msp430-gcc.git / blobdiff